The term Timber is applied to wood of sufficient size to be adapted for building or engineering purposes, whether it be standing in the forest or after it is felled. While the timber forms part of the growing tree, it is called standing timber; when felled, it is called rough timber. After the rough log is converted—that is, sawn into the various forms for which it appears best adapted—the products are then known as sided timber, balk, thick-stuff, plank, or board, according to the shape and dimensions of the pieces.

It is proposed in the following article to consider this subject in three or four principal lights; as, the growth and cultivation of timber; its use for constructive purposes; the supply of timber from foreign sources; and the most efficacious means for arresting its decay. In the articles Ship-Building and Strength of Materials much additional information regarding timber will be found.

If we examine the cross-section of the trunk of a tree, we shall find it to consist of three principal parts—namely, the pith, the wood, and the bark—the perfect or heart-wood occupying the larger portion. As all timber trees belong to the exogenous tribe of plants, which gain their increase by addition to the external surfaces, it therefore follows that the wood of oldest growth is found in the centre of the tree, and that the several concentric layers are younger in proportion as they recede from the centre. Around the perfect wood there is seen a concentric belt of younger growth, which has not yet attained to the maturity of the heart-wood. This belt is called the albumen or sap-wood; around it is another concentric belt, called the liber or inner bark, surrounded again by the outer bark. The centre of the heart-wood is occupied by the pith; and there is a communication between the pith and the bark that is maintained by what are called the medullary rays, which, as their name expresses, radiate from the pith, in the centre of the perfect wood, to the external coating of the tree, the bark. From their hardness and compactness the medullary rays may serve, in some measure, to resist the pressure of the accumulating annual rings, and to keep open the tubes for the passage of the sap in the interior of the tree. When cut in a sloping direction, they produce the beautifully-varied appearance called figure in ornamental woods. The pith, which seems to perform an important part in the growing economy of the tree while it is still young, appears afterwards to lose its utility; for as the central portions of the tree become indurated and formed into heart-wood, the pith is then nearly or altogether obliterated.

The first English writer on timber was the celebrated Evelyn, who published his Sylva, or Discourse of Forest Trees, in 1664. This book still continues one of the standard works on the subject in our language. In 1774 a new edition of it, with most extensive notes, and also engravings of the trees mentioned in the text, was published by the celebrated Dr Alexander Hunter of York. The last edition with these notes was published in 1825. In France the two celebrated philosophers, Buffon and Du Hamel, have each devoted a great portion of their useful lives to the investigation of the physiology of timber, and their writings on the subject have long been the text-books of arborists. In modern times, the phenomena of the growth of plants have occupied the attention of many men, some of whom have eminently distinguished themselves in this particular branch of natural history.

The experiments on the physiology of trees so successfully prosecuted by Mr Knight, president of the Horticultural Society, deserve especial notice. He removed a ring of bark, about half an inch in breadth, from a number of trees, and then compared the growth of these trees with that of others not so treated. This was done early in the spring, and in every case he found the result to be the Knight's same; namely, that those parts of the stem and branches which were above the incision, and had a communication with the leaves through the bark, increased rapidly in size, while those below the incision scarcely grew at all, until a new communication was obtained with the leaves through the bark; the increase of the timber thus evidently depending upon the growth of the leaves.

These experiments were so far conclusive as to establish Mode of that the current of sap which ran upwards from the roots, was not impeded in its passage by the annular incisions and the removal of the belt of bark; but that it was probably the downward current which was interrupted, and also that it was this downward current by which the annual increase of the tree was effected. By a series of experiments with coloured infusions, Mr Knight traced the upward current through the pores of the wood beyond the annular incisions in the bark, and found that it had neither coloured the bark nor the sap between it and the wood. He traced the coloured infusion along the leaf-stalk into the leaf, through one series of vessels; and he observed another series of vessels which were conveying a colourless fluid in an opposite direction, that is, out of the leaf. He traced this second series of tubes downwards, and found that they entered the inner bark, and, without having any communication with the tubes of the wood, descended through the inner bark from the very extremities of the leaves, apparently to the points of the roots. Mr Knight considers that there are two series of these descending tubes, one of which forms the new annual layer of albumen, and the other the new annual layer of internal bark. It thus appears that the sap is conveyed upwards, through the pores of some part of the wood, into the leaves, and that when there, probably by its exposure to light and air, and by the evaporation which takes place, it undergoes some peculiar process of elaboration which fits it for contributing to the sustenance and growth of the tree. It also appears that the cause of the growth is the deposition which takes place in the downward passage of this perfected sap. The sap, after this curious preparation in the leaves, is called cambium.

The same persevering physiologist then pursued his investigations a step farther. He took trees, and not only removed a ring of bark, but also a ring of the younger wood, to such a depth as to cut through and remove the whole of the albumen. These trees did not exhibit the slightest symptom of vegetation in the ensuing spring; which fact evidently proved that the ascent of the sap had been prevented by the removal of the albumen; for the previously-mentioned experiment had shown that the removal of the bark was not attended with such an effect.

It is the generally-received opinion, that the ascent of the sap through the albumen is the reason why this gradually becomes perfect wood, in consequence of the deposition of matter which then takes place and fills up its pores; so that the rationale of the process seems to be, that the sap of each year deposits a certain amount of nourishment in its upward passage, which goes to strengthen and solidify the sap-wood (or albumen) of previous years; that then, after being elaborated in the leaves, this same sap becomes cambium, and in its decent adds bulk both to the albumen and the bark. It must, however, be observed, that there is not in timber any appearance of a gradual change from albumen to perfect wood. On the contrary, in all cases the division is most decided; one concentric layer being perfect wood, and the next in succession being sap-wood. Mr Knight gives it as his opinion, that towards the conclusion of summer, the true sap—that is, the cambium—simply accumulates in the albumen, and thus adds to the specific gravity of winter-felled timber. He thinks that the true sap descends through the albumen as well as through the bark—that is, that "the superabundance of true sap is there deposited, and enriches the upward current of aqueous sap, or the sap of the ensuing spring."

In confirmation of this, he tested the ascending current of spring sap, extracted from the trunks of trees at various heights, and found that the specific gravity increased with the height, and that the taste also very sensibly altered. He argues from the foregoing facts, that by girdling trees in the spring, and suffering them to grow until the ensuing winter, the wood above the girdling would be increased in specific gravity. In one experiment, in which the belt of bark had been abstracted for several years, he found that the specific gravity of the wood above was 0·590, while below it was only 0·491; and also that the albumen had acquired a greater degree of hardness, and consequently of durability. This is important, as Du Hamel has very conclusively established by experiment that the strength of timber of the same species varies very nearly as its weight.

The leaves of a tree perform the important office of inhaling and fixing in a solid form the gaseous food contained in the atmosphere. In the day-time they absorb carbonic acid from the air, which then becomes decomposed, and the oxygen is given off; this process being reversed at night, although in a slower degree. About one-third of the entire carbon of which the tree is composed is believed to be thus extracted from the atmosphere.

As the sap descends, it forms a layer or ring of sapwood and inner bark, by which the circumference of the tree is gradually increased year by year. By counting the number of these so-called "annual" rings, which are very distinct in some species, it is generally supposed that the age of a tree can be ascertained. It is now believed, however, that this is not always a true indication of the age of a tree, a "ring," more or less distinct, being formed in the wood by any sudden augmentation of growth, consequent upon a track of warm weather succeeding a colder season, or a moist period succeeding to extreme drought in summer. It may thus happen that several rings are formed in the wood during one year's growth only. Although the sap of a tree is most active in the spring, and during the season of vegetation, it has been ascertained that it is never altogether stationary, except during severe frosts.

When the induration of the sap-wood has reached its extreme limits, the proper time has arrived for the tree to be cut down. This may arise, however, from other causes than mere old age. Ungenial climates and situations check the free circulation of the sap, and the new layers of wood and inner bark are thus imperfectly formed or greatly attenuated in substance, and the tree shows all the symptoms of premature old age at a period of its growth, when, had it been reared under more favourable circumstances, it would have been still young and vigorous. External injury, by which water is admitted into the substance of the tree, will equally induce premature decay in a tree otherwise sound and flourishing. Hedge-row timber is particularly exposed to accidents of this kind, and the practice of planting valuable trees in such situations should either be sparingly adopted, or avoided altogether, more especially as the growing crops are much injured by them. At the same time, waste corners and outlying pieces of ground, perfectly suitable for trees, and indeed only profitable when planted, are too often left vacant in their native barrenness; for a wise Providence has so constituted the majority of trees, that they will flourish upon, and indeed prefer situations which are altogether unfit for the production of corn and other crops. This is chiefly owing to the small proportion of mineral nutriment which trees require in comparison with grain. For several remarks of much practical value occurring in this portion of our article, the author is indebted to the professional knowledge and sagacity of Mr John Blenkarn, who has recently published an excellent treatise on British timber trees. A certain portion of the article TIMBER, written for the preceding edition of the Encyclopaedia Britannica, has also been incorporated in the present article.

The mineral constituents of timber vary with the nature of the soil on which it is grown, but these consist chiefly of the carbonates of potash, soda, lime, and magnesia, with generally a small portion of the sulphates, chlorides, and phosphates of the same substances. The following table exhibits the weight of mineral ash remaining after the combustion of 1000 lb. weight of different woods, all equally dry when weighed:

| Wood | Ash (lb.) | |------------|-----------| | Elm | 19 | | Poplar | 20 | | Willow | | | Beech | 2 to 6 | | Birch | 3½ | | Oak | 2 | | Pine | 1½ to 3 | | Ash | 5 to 6 |

Although in most parts of England there is soil favourable to the growth of timber, it may well be supposed that of soil on all soils are not equally favourable to all kinds of timber, nor will they produce timber of equally good quality. Thus, while England is, par excellence, the country of oak timber, the Sussex oak has always been celebrated as superior to all others. In France, the oak of Provence enjoys a similar reputation. Still, an oak-tree grown in a soil but ill adapted for it, as, for instance, a marshy soil, will retain its superiority of species over the inferior timbers, such as willow and poplar, to which such a soil is less unfavourable, although in quality it will fall far short of the standard of perfection for oak timber. In fact, oak grown on such soils will, in some measure, partake of the qualities of the timber to which they are better adapted, and be of more open texture, of softer fibre, and of less durability, than average oak timber. Oaks of slow growth, those for instance from the mountains of Scotland, and from Cumberland and Yorkshire, are proverbially hard and durable. The oak from marshy soils is often of a dull-red colour, or has "foxey" and acci-stains in it, as this incipient decay is called. These stains, dents are generally around the heart of the tree. Timber grown in loose soils is often what is termed "quaggy;" that is, the centre of the tree is full of shakes and clefts. Sometimes liable, a shake will extend around a great portion of the trunk, between two of the annual concentric layers, so as to divide them from each other. This is called a cup-shake, and the timber is said to be "cuppy." It is not attributable to the soil, but is supposed to originate in the effect of frosts on the aqueous sap in its ascent. When the albumen of a tree has been wounded, or a branch improperly lopped or damaged, the subsequent growth of the tree will cover it, and it is then called a rind-gall, which, should the injured part have had time to become decayed, or partially so, or even sodden with the rains, will frequently cause an extensive rottenness in the plant. This is remarkably the case with elm timber. "Deatness," probably dottiness, which is a spotted or speckled appearance, like small stains in the wood, is most commonly a disease of beech timber; it is, however, occasionally seen in all, and frequently in the American oak. These diseases are in general incidental to the soil.

In treating of soils in connection with the qualities of the Timber which grows upon them, it may be necessary to remember that the object is not to compare various sorts of timber, but to compare the differences in the same species in connection with the soils which produced them. It may also be observed, that as oak is by far the most valuable timber of English growth, the general inquiries we may enter into in the course of this article principally apply to it, unless other species of timber are particularized.

We have already casually adverted to marshy soils, and to the state of the timber grown on them. The grain of such timber is open, its colour of a deep yellow, sometimes with a tinge of red, especially towards the heart; the texture is soft, and the fibre coarse. The quantity of albumen, and also of bark, is large in comparison with the quantity of perfect wood, and the outer surface of the bark is very coarse and rough. The wood splits easily, and when split it has not the same bright and varnished appearance possessed by the best timber. The chips from the axe do not cling well together, but fall into separate fragments; and a shaving or a small splinter may be easily crumbled between the finger and thumb. When such timber is weighed, although it is far more saturated with moisture, it is of less specific gravity; and when weighed after seasoning, the weight lost will be comparatively greater. Such timber, it is evident, will be more subject to decay, and to become worm-eaten, the softness of its texture inviting the attacks of insects.

These peculiar characteristics attach more or less to timber grown in all soils which are of a moist nature, whether they are marshy, or wet from long continued periodical inundations. They also apply to timber grown in deep sandy soil, in which almost the only nutriment for the roots is the water which percolates downward, and the bottom damps which rise upward through it. In all these soils the timber is of rapid growth, and the trees attain early to a large size. A similar result attends the timber grown in sandy soils on a clay bottom, for the water which falls, not being able to penetrate the clay, cannot escape, and the roots of the trees are therefore virtually in the same circumstances as if they were growing in marshy land. As a general axiom, timber trees have an antipathy to stagnant waters; and, therefore, these observations on marshy soils, and on sandy soils with clayey bottoms, refer themselves to this fact. The soil generally the best adapted for the growth of timber appears to be a rich loam. This may have a considerable admixture of sand, without any apparent detriment to the timber. In such soils roots can penetrate and spread without difficulty, while the loam is capable of retaining sufficient moisture to dissolve and hold in solution the various substances that are found combined with it, so as to fit them to be absorbed as food by the roots of the plants. If the soil be too sandy, it neither retains the moisture sufficiently long in it, nor does it contain adequate nutriment. If, instead of a loam, some of the very stiff clays be mixed with the sand, they do not counteract this quality; for although such clay is capable of combining with a great quantity of water, it will not easily absorb and mix with it; and the tender roots have great difficulty in penetrating the masses of clay. For these reasons, soils composed wholly of stiff clay are not favourable to the growth of good timber, but the lighter clayey earth produces very fine oaks. As has been before stated, sand or gravel, with a large mixture of rich loamy earth, is precisely that sort of dry generous soil which affords ample nourishment to the roots of trees, and allows of their spreading themselves freely in search of it.

Of all timber oak accommodates itself most easily to soil; growing in almost every thing but sterile sand, if there be sufficient depth of stratum. Wherever oak will grow, even in those soils the least genial to its growth, it is a valuable timber. This fact cannot be too often pressed upon the attention of landholders. It is well adapted for planting in hedge-rows between arable fields, because it is found to be less destructive to the undergrowth than almost any other timber; and as its roots seek their nourishment deep in the soil, they not only do not impoverish the ground for the growing crop, but are themselves protected from any injury which they might otherwise sustain from the tillage. Oaks so planted require, however, to be protected during several years, as their early growth is slow. The timber grown in such exposed situations is seldom large; the trees are stunted and crooked; but this rather increases their value for ship-building purposes, as they convert as compass or knee timber. The timber of hedge-row oak is very close grained; that of park-grown oak is more open, and the trees being better protected, spread more freely, and grow to a very large size, with strong lateral branches; while forest-oak will frequently grow to a great height without pushing out any lateral shoots. Forest-oak is invariably inferior in quality to that which grows singly; and in forests the trees that grow on the skirts are always the best timber. The oak flourishes in variable climates, which is probably the cause of the superiority of the English oak. The roots of the oak strike very deep into the soil, at the same time those of no other tree, perhaps, take so wide a range. The top root of an oak has been known to descend to a depth equal to the height of the tree.

A curious fact has been established in connection with the supply of food for trees, which proves that there is not between only a proportion between the spread of the roots and that of the branches of a tree, but that the branches on any one side of the trunk of the tree are dependent for their support on the roots which protrude from the trunk on that same side. Both Buffon and Du Hamel found experimentally, that when the limbs and branches of any part of a tree showed symptoms of decay, the corresponding roots were invariably in a diseased state. They also found, that on that side of a tree from which the roots had pushed most vigorously, the annual concentric layers of wood were thicker, and that, consequently, the form of a section of the tree would be eccentric towards that side.

The determination with which the roots of trees seek out for themselves the best localities is surprising. If will seek trees of different species be growing on the edge of a marshy place, that tree which requires most moisture will push its roots towards the marsh, while that which requires a dry soil will push its roots into the dry firm ground. Du Hamel relates an instance in which he dug two trenches, crossing each other at right angles; he then returned the soil into these trenches, and planted a tree at the point of their intersection. Some years after, upon examining the roots, it was found that they had invariably pushed into the four lines of trenches, leaving the intermediate undisturbed earth wholly untouched.

An equally important consideration with the quality of the soil is its quantity—that is, its depth below the surface. In speaking of soils in connection with the growth of timber trees, it must of course be understood that it is not merely the surface-soil which is meant, but that soil in which the roots of the trees would push and spread, the soil for several feet in depth. It often happens, indeed, that the surface-soil may be well adapted for tillage and for vegetation in general, and yet the sub-soil, that which is essential to the growth of timber trees, may be totally incapable of supplying them with nourishment. Trees which grow singly, as in hedge-rows or in parks, do not require an equal depth of soil with those that grow in forests, because they have facilities for spreading their roots in search of food. But for forest-trees, whether oak, chestnut, or birch, a depth of at least 4 feet of appropriate soil is absolutely necessary for the production of fine timber trees. Elm and ash do not require so great a depth.

Buffon has given a scale for the ages at which it is desirable to fell timber, dependent upon the depth of soil in which it grows. He says that a depth of from 2 to 3 feet of soil will not support a tree in a thriving condition for a longer period than fifty years. From 3 to 4 feet of soil will enable the tree to go on improving till about seventy years of age; and in soil from 4 to 5 feet deep it will flourish for a century. These periods are for strong and favourable soils. In lighter soils, at least ten years must be taken from each period, and the timber will then also be inferior in quality. As a general rule, the more generous and favourable to the growth of the timber the soil may be, the longer it is advantageous to wait before felling it. Trees should never be allowed to become stag-headed—that is, to have their upper branches bare of leaves. It is in the top branches that the first symptoms of the decline of the tree are to be perceived. The leaves there acquire a faded, weakly appearance, gradually diminish in number, and finally the branches become barren of foliage and decay. The least appearance of want of vigour in the top of a tree should be the signal for its being cut down; and even then it is a sure token that the timber is past its prime.

The nature of the soil in a track of country may be ascertained either by opening it, or by observing the plants which grow upon its surface. Thus, if plants which flourish only on marshy land are found at all times of the year on any particular track, we may assume that track to be marshy land, whatever its temporary appearance may be. The nature of the subsoil may often be ascertained by examining the ditches. The goodness of earth may be tested, approximately, in the following way. If a hole be dug out, and the whole of the excavated earth can be afterwards returned into the hole, the soil is poor; but if, on the contrary, there is an excess, its quantity is a criterion by which to judge of the richness of the soil.

Although, as we have seen, too much moisture is unfavourable to the growth of good timber, a deficiency of it must equally be guarded against; the timber then suffering, not in quality indeed, but in size. Wood grown under such circumstance—as, for instance, the Scotch mountain-oak—is extremely heavy, hard, and dense, and when not "overgrown," or allowed to attain too great an age before being felled, is very durable, and little liable to shrink or warp. Mountain-oak is therefore well adapted for furniture and panelling, &c. As a general rule, the quicker the growth of the tree, the more it will shrink when converted into timber.

These general remarks afford an idea of the difference in the appearance and qualities of timber grown on good soil from that produced on bad soil. It may, however, be desirable to enter a little more into detail. An oak-tree, grown on the soil adapted to the development of its best properties, not only has its concentric rings thin and close together, but they are also of very uniform thickness, and the texture of the grain is fine. When the wood is split, it has a glossy, varnished appearance, and is of a very pale yellow or straw colour. There is sometimes as much as one-fourth difference in weight between samples of oak timber; and the heaviest loses a much less proportion of its weight in drying, and will also, if immersed in water, absorb less than the lightest. The amount of sap-wood in the best timber is comparatively small, and the bark is thin and of a smooth, even texture. In breaking such wood, it produces a sharp, decided noise. Having but little moisture in its composition, and being less hygrometric in its nature than wood of more open texture, it is little subject to decay; and its grain being hard, it is not easily pierced by insects.

The great size to which oak-trees will attain, when favourably situated as to soil and locality, is truly astonishing. Timber. The celebrated Chapel Oak of Allonville, in the Pays de Caux in France (which is still standing, we believe), measures at its base 35 feet in circumference, and at 6 feet above the level of the ground it is 26 feet in girth. It is record hollow, the interior having been fitted up as a chapel in 1696, and being still employed in that capacity. The computed age of this tree is between eight and nine centuries. A very large oak was felled in Monmouthshire in 1791; when converted, it produced the following enormous quantity of timber:

| Item | Quantity | |------|----------| | Main stem, 91 feet long, when sided | 330 cub. ft. | | Branch, 29 feet long, sided 17 inches | 58 " | | 24 " | 19 " | | 19 " | 17 " | | Two main slabs produced | 861 feet of 3-inch plank, making, with other conversions | 216 " | | 13 sided knees, taken together | 217 " | | Other minor but useful conversions | 276 " |

Total | 1195 |

The weight of useful timber in this tree was nearly 30 tons. The bark weighed 3 tons, 17 cwt., 3 qrs. But the largest oak on record, known as Damory's Oak, grew in Dorsetshire, and was used as an ale-house. It was 68 feet in circumference, and the room formed in it was 16 feet in length. This tree was blown down in 1703. The Cowthorpe Oak, near Wetherby, in Yorkshire, measured (in 1768) 404 feet in circumference at 4 feet from the ground, the height of the tree being 85 feet. The Bentley Oak measured (in 1759) 34 feet in circumference at 7 feet from the ground. The Boddington Oak, in the Vale of Gloucester, measures, at 3 feet from the ground, 42 feet, and at 6 feet from the ground, 36 feet in circumference.

There are not less than 140 species of oak known, and although there are many sorts cultivated and growing in England, botanists and arborists agree that there are principally two varieties; these are, the Durmast oak, and another, which is commonly called the old English oak, although both are supposed to be indigenous. In the Durmast oak, the Quercus sessiliflora, the acorns grow in clusters close to the twig, and the leaves are set on short leaf-stalks, while in the old English oak the Quercus Robur, or Quercus pedunculata, the acorns grow generally singly, at most two together, on stalks of from 1 to 2 inches in length, and the leaves are close to the twig, without the intervention of any length of leaf-stalk. These are the principal distinguishing marks between the two varieties. Many writers attempt to draw distinctions from the colour and shape of the leaves, and the colour and appearance of the bark; but it is doubtful whether these may be depended upon, as, from a careful examination of the evidence, it is more than probable that the colour and appearance vary much with the soil and locality. There is no doubt, however, as to the comparative inferiority of the timber of the Durmast oak. Almost all the English writers on timber have asserted it, and both Buffon and Du Hamel corroborate their assertions, and give a most decided preference to the oak bearing large acorns on separate stalks over the oak bearing acorns in clusters; which characteristics are just those which distinguish the English from the Durmast oak.

In favourable soils, the old English oak has seldom more than 12 to 15 concentric rings of sap-wood; but in the sap-wood Durmast oak there are frequently from 20 to 25, or even wood in 30. This seems to prove the inferiority of the Durmast oak; for it is an established fact, that the best hardwood trees, timber is that in which the proportion of heart-wood to sap is the largest. The Spanish chestnut has usually but 5 or 6 rings of sap-wood; English elm, about 10; white larch, 15; Scotch fir, 30; yellow Canada pine, 42; Memel fir, 44; and red Canada pine as many as 80 to 100. As a general average of the size of oak timber, 56 cubic feet for each end or log of rough timber, and 30 cubic feet for each end of sided timber, may be assumed as tolerably correct. In order to convert rough timber into sided timber, about two-thirds the diameter of the rough log, in the middle of its length, is assumed as the most advantageous siding; and, on an average, it is estimated that not above one-third of each log or end of rough timber is used in the principal conversion from it, and this principal conversion is estimated to be about three-fourths of the total conversions.

With reference to the size that an oak will attain in a given number of years, much must depend upon the soil and the situation. The plan adopted by the late Duke of Portland of planting tablets of iron or stone with the trees, with the date inscribed upon them, will probably throw much light on this subject. Mr Blenkarn adduces the following case:

Three thriving oaks, growing on a hard, gravelly, and poor soil, were felled in Nottinghamshire, which, on an average, girdled 15 feet at 3 feet from the ground, and each tree contained about 430 cubic feet of timber. These trees were known to have been planted in 1692 or 1693, and they were above 149 years old (say 150 years) when they were felled. As they were perfectly sound, and were yearly increasing in size, it is probable that had they been allowed to remain another century, their bulk and cubic contents would have increased at least one-half.

The value of these trees when cut down was more than L.120, a sum equal to 30s. per acre (without taking interest into account) for the land they occupied during the 150 years of the growth,—a reply to those who assert that timber will not pay the rent of the ground it occupies, or injures by its shade. For the first 50 years the land would not be much injured by those trees; and as they grew older the acorns, as food for swine, would compensate for the loss of herbage under the trees. But the land on which these trees grew was not worth 15s. an acre when they were felled, and of course was much less valuable when the trees were planted.

"It frequently happens," says Mr Blenkarn, "that proprietors of large estates have not the slightest idea of the value of the timber growing upon them, regarding the trees on the property as merely an ornamental accessory, little supposing that they may be worth more than half of the value of the estate estimated on the basis of the rental. It may be further affirmed that, on most large estates, a great portion of the timber could be cut down to the benefit of the trees which are left standing. An acre of oak woodland, containing 100 loads of timber (which is a low estimate), is worth L.650 at a moderate computation; and 50 acres of such property would therefore yield L.32,500 worth of timber." This calculation, offered by a professional surveyor, certainly holds out a strong incentive to planting, without taking into account the beauty imparted to the landscape, the shelter obtained for cattle, the cover for game, and other advantages. It is a well-known fact that estates abounding with timber will command a high price in the market, and are eagerly sought after, in preference to others possessing a better soil but destitute of trees.

Few proprietors have been more successful in their planting operations than the late Duke of Portland, at Welbeck in Nottinghamshire. The greatest part of his plantations occupy rough "forest-land," undulating in a succession of hill and dale. The soil is a mixture of sand and gravel, the hills abounding with gravel and the valleys with sand; and it is the hilly grounds that have been planted. This has increased the value of the low grounds for cropping, by the shelter afforded by the trees. The following was the modus operandi adopted by his Grace. After fixing upon the portion of the forest-land to be planted, some well-sheltered valley near the centre of the intended plantation was chosen in which to form a nursery. A few acres of this were surrounded with a close fence to keep out hares, deer, &c.; and the whole was then trenched to His method the depth of about 20 inches, excepting a broad road in of plant the middle for carting away the young trees. The gravelly ing soil of the nursery was afterwards treated with lime, and a The nur crop of turnips or cabbages taken from it, which was eaten ery off by sheep. This brought the land into good order for all sorts of tree-seeds; the oak, however, being the species of timber almost exclusively planted at Welbeck. After the turnips were eaten off in the autumn, the ground was again well dug. So soon as the acorns fell, a good quality was selected, and they were then sown in drills so thickly as nearly to touch each other. The rows were 1 foot apart, and between every fifth row an alley of 2 feet in width was left. While the acorns, or other tree-seeds, are in the ground, great care must be taken to keep them from vermin. After the seeds come up, the beds will require only to be kept clean from weeds until the plants want thinning, and as they will grow more in one wet season than in two dry ones, the time for doing this is best known by watching when the tops of the young trees in the adjoining rows meet. They should then be thinned by taking away one row on each side of the centre row, which leaves the remaining three rows at the same distance apart as the breadth of the alleys, the trees in each row being spaced to about the same distance, or 2 feet apart. They may remain at this distance till their tops again meet, when every other row should be taken up, the remainder now standing 4 feet asunder. When these arrive at the height of about 5 feet, they should be finally planted out. In taking up the last two sizes from the nursery, the Duke's gardener dug a trench 2 feet in depth at the end of each row, he then undermined the plants, and let them fall gently into the trench with their roots entire. Very much of the future success of the plantation depends upon the young plants being well taken up and re-planted without injury to the roots, as much earth being retained about the roots as possible. While in the nursery they require pruning every winter by shortening the strong side-shoots, and taking off one head from all such as have two.

In commencing to form the plantations, these must be at The planta first proportioned in size to the stock of young trees in the tions. nursery. "We always plant thickly," writes Mr Speechly, the Duke of Portland's forester, "as well as sow plentifully at the same time, provided it be a season in which acorns can be had; so that all our plantations answer in a few years as nurseries to succeeding plantations.

"If the ground to be planted has not been already prepared for that purpose, it should be fenced in at least a year before it is wanted, and immediately got into order for a crop of turnips. The addition of two chaldrons of lime per acre will be of great service to sandy soils, as it will not only ensure a better crop of turnips, but it will bind the light soil and prevent its being blown from the roots of the young trees when it comes to be planted. For this reason, also, the land should be planted within two years after being ploughed up from pasture, and before the turf is too far decayed. It will be necessary to have a part of the turnips eaten off soon in the autumn, to get the ground ready for early planting, as the trees succeed best which have been put in early in the winter. The turnips having been eaten off by sheep, the ground is ploughed with a sub-soil plough to the depth of 12 or 13 inches. This ploughing is of great service to the plants when young, and, besides, it saves much trouble in digging the holes.

"After the ploughing is finished," continues Mr Speechly, "we divide the ground into quarters for the planting by the ground ridings. It will be a difficult matter to describe the laying out of the ground for this purpose, so much depending upon the taste of the person employed in this office. Between Timber.

the hills, towards the outsides of the plantations, we frequently leave the ridings from 60 to 100 yards in breadth, and contract them towards the middle of the woods to the breadth of 10 or 12 yards; and on the tops of the hills, where there are plains, we frequently leave lawns of an acre or two, which makes a pleasing variety. In some of them we plant the cedar of Lebanon at good distances, so as to form irregular groves; and this tree seems to thrive to admiration on the forest-land. On the outsides of the woods, next to the ridings, we plant evergreens—as hollies, laurels, yews, junipers, &c.; and these we dispose of in patches, sometimes keeping the several sorts entire. At other times we intermix them for variety, but not so as to make a regular screen or edging. Our design in the distribution of these plants is to make the outsides of the woods appear as if scalloped with evergreens, intermixed sometimes with rare trees, as the tulip-tree, &c., &c.

After the ground is laid out into quarters for planting, we assign certain parts to beech, larch, Spanish chestnut, &c. These we plant in irregular patches here and there throughout the plantations, which, when the trees are in leaf, has the most pleasing effect, on account of the diversity of shades. After these patches are planted, or marked out for that purpose, we then proceed to the planting in general. We always begin by planting the largest young trees of every sort, and end our work with those of the smallest size; were we to proceed otherwise, the making a hole for a large-sized tree, after the small ones are thickly planted, would cause the greatest confusion. Birch is generally the sort of tree we make our beginning with, which we find will bear to be removed with the greatest safety at the height of 6 or 7 feet, though we commonly plant rather under than at that size. This sort of tree we are always supplied with from our plantations of five or six years growth. But before I proceed to the taking them up, it will be proper to inform you that, in the planting season we divide our hands into four classes, which we term takers-up, pruners, carriers, and planters; and now I shall describe the several methods of doing this work.

First, in taking up, we have the same care to take up with good roots in the plantations as was recommended in the nursery, though we cannot pursue the same method; but in both places, so soon as the plants are taken up, we bed them in the ground in the following manner:—Dig a trench at least 15 inches deep, and set the young trees therein, with their tops aslant, covering the roots well as you go along, and almost half-way up the stem of the plants, with the earth that comes out of a second trench, which we fill in like manner, and so proceed until we have a load (more or less) ready to be carted away. In our light soil this trouble is not great, and we have always our plants secure both from their roots drying and from their suffering by frost. We have a low-wheeled waggons to carry them from the heaps where they are bedded to the pruners, and we generally take two loads every other day. When they arrive, the planters, pruners, &c., all assist to bed them there in the same manner as already described. We have a portable shed for the pruners to work under, which is also convenient for the rest of the work people to take shelter under in stormy weather. From these heaps the plants are taken only so fast as they are wanted for pruning, which work we thus perform:—Cut off all the branches close to the stem to about half the height of the plant, shortening the rest of the top to a conical form in proportion to the size of the plant; and in pruning the roots we only cut off the extreme parts that have been bruised by the taking up, or such as have been damaged by accident, wishing at all times to plant with as much root as can be had.

As soon as they are pruned they are taken to the planters by the carriers, who are generally a set of boys, with some of the worst of the labourers. The planters go in pairs, one makes the holes, and the other sets and treads the plants fast, which work they commonly do in turns. In making the holes, we always take care to throw out all the bad soil that comes from the bottom. If the planting be on the side of a hill, we lay the bad soil on the lower side of the hole, so as to form a kind of basin, for without this care our plants would lose the advantage of such rains as fall hastily. We at all times make the hole sufficiently large, which is done with great ease after one deep ploughing. Before setting the plant, we throw a few spadefuls of the top soil into the hole, setting the plant therein with its top rather inclining to the west; then fill up the hole with the best soil taken from the top, taking care that it closes well with the roots, leaving no part hollow. When the hole is well filled up, one of the planters treads and fastens the tree firmly with his feet, while his partner proceeds to make the next hole. The fastening a tree well is a material point in planting, for if it once becomes loose, the continual motion which the wind occasions is sure to destroy the fibres as fast as they are produced, which, if not prevented, must end in the destruction of the tree. It is to guard against this mishap that we take off so much of the top, as has been described while speaking of pruning.

We plant about three or four hundred birches of the proper large size to every acre, and nearly the same number of the first-sized oaks; we also plant here and there a beech, different larch, Spanish chestnut, &c., exclusive of the patches of these sorts of trees before planted. We then proceed to plant plentifully of the second and lesser-sized oaks, and last of all, a great number of the small birches, which are procured from the woods at a cheap rate. These we remove into the succeeding plantations after the term of five or six years. Of the several sizes of the different kinds of trees, we generally plant upwards of 2000 plants upon an acre of land, all in an irregular manner.

After the planting is finished, we then sow the acorns (provided it be a season that they can be had) all over the plantation, except among the beech, larch, &c., in the afore-said patches. Great care should be taken to preserve the acorns intended for this purpose, as they are very subject to sprout, especially soon after gathering; the best method being to lay them thin in a dry airy place, and give them frequent turnings. We sow these acorns in short drills of about a foot in length, which work is done very readily by two men, one with the acorns, another with a hoe for making the drills and covering the seed. We are of opinion that the plants grown from these acorns will at last make the best trees, though oaks, transplanted small, grow equally well for a number of years. It is probable, however, that a tree with its top root undisturbed will in the end grow to a much larger size. When the whole is finished to a convenient distance round the pruners, their shed is then removed to another station, and the work is proceeded with as above.

It is preferable to have the planting all finished by the end of February, especially for trees of the deciduous kind, for plants but from disappointments occasioned by the weather are sometimes detained to a later season. Towards the end of April, when the ground is moist, it will be of great service to go over the whole of the plantations, and fasten all such trees as have become loose since their planting; after this, nothing more will be required till the month of June, when we again go over the whole with hoes, cutting off only the tall-growing weeds, for the sooner the ground gets covered with grass in our light soil so much the better. I own there is something slovenly in the appearance of this method; and on some lands I would recommend keeping the ground clean-hoed for some time at first, as also planting in rows, which in that case would be necessary. More than once I have tried this method on our forest-hills, and, Timber always found, after every hoeing, that the soil was taken away by the succeeding winds into the valleys. The evaporation from sandy soil is so rapid, that we find the plants stand a dry season much better when protected by grass; and whoever thinks that the latter will choke and destroy seedling oaks will, after a few years' trial, find himself agreeably mistaken. I have even recommended sowing the poorer parts of the hills with furze or whin-seed as soon as they are planted. We have sometimes permitted the furze to grow in the plantations by way of shelter for the game, which, though it seems to choke and overgrow the oaks for some time, yet, after a few years, we commonly find the best plants in the strongest beds of whins. This shows how acceptable shelter is to the oak while young, and experience teaches us that the oak would make but slow progress on the forest-hills for a number of years at the first, were it not for some kind nurses. The birch seems to answer best for this purpose, and therefore it is that that tree is so plentifully introduced in oak plantations. For although the several kinds of fir-trees would appear to promise greater shelter, they neither grow so fast on the forest-land as the birch, nor will the oak thrive under them. When a plantation is on a plain, a screen of fir-trees for its boundary is highly beneficial.

"We continue to cut down the tall growing woods two or three times the first summer; and perhaps the next once, which is all we do in respect of cleaning. The next winter, after planting, we fill up the places with fresh plants where they have miscarried; after which there is little to be done till about the fourth or fifth year, by which time the small-sized birch and seedling oaks will be grown to a proper size for transplanting. In the thinning of these, due care must be had not to take too many away in one season, but when properly managed there will be a supply of plants for at least half a dozen years to come. About the same time that the lesser-sized birch wants thinning, the larger ones will require to have their lower branches taken off; so as to keep them from injuring the oaks; and this is the first profit of our plantations, the birch-wood being readily bought up by the broom-makers. This pruning we continue as often as required, till the birches are grown to sufficient size to make rails for fencing; we then cut them down to make room for their betters.

"By this time the oaks will be grown to the height of 12 or 14 feet, when they draw themselves up exceedingly fast; each plant seems, as it were, at strife with its neighbour, and, in a strict sense, they are so, and on no other terms than life for life, since he whose fate it is to be once overtopped, is soon after compelled to give up the contest for ever. After the birches are cut down, there is nothing more to be done but thinning the oaks from time to time, as may be required, and cutting off the dead branches as often as may be necessary. We are very cautious in doing the former, knowing well that if we can but once obtain length of timber, time will bring it into thickness; therefore we let them grow very close together for the first fifty years.

"And here it may not be improper to observe the progress the oak makes with us at Welbeck by describing them in two of our plantations, one of twenty-eight, the other of fifty years' growth. In the former they are in general about 25 or 26 feet in height, and in girth about 18 inches; the trees in the latter are something more than 60 feet in height, and in girth a little above 3 feet; these trees being in general about 50 feet in the bole, from which it will be seen that their tops are comparatively very small."

Although this excellent paper on the cultivation of timber was written nearly a century ago (being published in Dr Hunter's edition of Evelyn's Sylva, 1775), it may be said still to embody the best practice of the present day; and the flourishing appearance of the woods at Welbeck certainly attest the value of Mr Speechly's instructions. It should be remarked, however, that much doubt exists as to the propriety of transplanting the oak, since from the great length of its top-root (or tap-root, as it is frequently called), it is all but impossible to do this without injury, and trees thus treated are found not to thrive so well as those which have never been moved. The best season for planting on light ground is as soon as possible after the beginning of October, and for heavy, moist land, in February and March. When the quality of the ground varies very much, which is almost sure to be the case in extensive plantations, the species of the trees should be varied accordingly, and the appearance of the wood will be much more beautiful than if uniformly planted with trees of one kind. As the oak, however, fortunately thrives on almost any soil, no portion of the wood should be destitute of them.

Where artificial drainage becomes necessary, open drains are preferable to close ones, as being less liable to get choked up with the fibres of the roots. Strong clay soil (of which a great portion of wood-land consists), when so overshadowed by trees that the natural evaporation from the surface is much impeded, becomes almost impervious to water, and the stunted growth of trees, particularly the oak and the ash, and the dead branches in the tops of the oaks, called stag-heads, are mostly attributable to this cause. Good drainage has also the effect of increasing the temperature of the soil.

In large woods which are planted on nearly level ground, it is recommended to leave occasional open spaces or glades, in the thickest parts most remote from the boundaries, left unencumbered with brush-wood. These tend greatly to encourage the free circulation of air through the wood, a point of considerable importance in the economy of vegetation. These glades may be rendered very beautiful by planting in them a few choice specimens of ornamental trees, which will generally thrive well in such a situation in consequence of the protection afforded by the surrounding wood. In thinning woods, care should be taken to remove such trees as show any signs of decay, or when one tree interferes with the growth of another, the cleanest, straightest, and those with well-formed compact heads being alone reserved for timber. The oak and chestnut, as the most enduring trees, should be chiefly left to posterity; the beech, ash, and others being cut down as they arrive at maturity.

In consequence of the great value of the bark of oak, it is the practice to fell the timber in the spring of the year, because then the bark is easily detached from the tree, while the bark of winter-felled timber is lost. There can be little doubt, however, that the durability of the wood is much deteriorated by this practice. It was a received opinion among the ancients that timber should be felled in the fall of the year; and not only do modern experiments confirm this opinion, but modern discoveries as to the flow and return of the sap, and its nature at various seasons, tend to show the reason for its correctness. The practice which almost all the eminent arborists have recommended, and supported by their experiments, is to bark trees standing in the spring, and then allow them to remain in this state at least one twelvemonth. This was not an uncommon practice in some of the midland counties of England, and was first strongly recommended in the reign of James the Second by Dr Plott, an arborist of great celebrity at that time. Buffon presented a memoir in 1738 to the Royal Academy of Sciences in Paris, "On increasing the Solidity, Strength, and Durability of Timber;" for which purposes it was recommended to strip the tree of its bark during the season of the rising of the sap, and then to leave it to dry completely before being felled. Du Hamel gives most minute accounts of experiments made by himself, all tending to the same conclusion; and Dr Hunter, in his notes on Evelyn's *Sylva*, says, "that by stripping off the bark, and allowing the tree to stand and die before it is cut, the sappy part becomes as hard and firm as the heart." Here is a collection of opinions, of such weight, that the general fact which they assert must be considered to be established beyond contradiction. Buffon also says that he caused pines, firs, and other species of evergreens, to be barked standing; and as he found them live longer after the operation than oaks which had been also stripped, he considered their wood acquired proportionately greater hardness, strength, and durability. He recommended the practice for fir-trees destined to be converted into ships' masts.

We shall now notice a few of the peculiarities of other trees most esteemed in this country for their timber.

The Elm, of which, like oak, there are two principal varieties, will not bear a damp soil with stagnant waters, but it thrives well in moist declivities, provided the land be not too rich. The trees grown on too damp a soil either die prematurely, or their timber is of a soft spongy nature, and prone to decay. There are two British varieties of this timber, the *Ulmus Montana*, or Wych elm, and the *Ulmus Campestris*, or, as they are sometimes called, the Scottish and the English elms. Of these the Wych elm is decidedly the most valuable as timber, and, when used in situations where it is kept constantly moist, is extremely durable; but no elm timber will bear the trials of change of temperature and moisture to which oak in all its varieties is comparatively insensible. The close and interwoven grain of elm, the absence of decided longitudinal fibre, and its power to resist rending from exposure to the heat of the sun, and the alternations of weather, cause its timber to be very useful for small articles, such as the blocks used in the rigging of a ship. It is valuable in many parts of the millwright's machinery, where the wood is subjected to cross strains or great friction. It is also valuable and much used both for the timbers and for the planking of ships below the surface of the water; and the planks of clinker-built boats are very generally of elm. There is one peculiarity about elm timber, namely, that the albumen or sap-wood is possessed of nearly equal power to resist decay with that which is matured; that is, when both are used in situations where they are not exposed to alternations in moisture. A variety of timber has of late years been introduced into the market under the name of Canada elm, or American rock elm. It is a smooth, even textured, pale-coloured, and strongly fibrous wood, almost devoid of knots, and admirably adapted for boat-building, and all works which require a flexible and close-textured wood. The Canada elm appears to have many of the peculiarities of toughness and flexibility which distinguish the ash. The elm-tree, which is much to be admired for the stateliness of its growth, sometimes arrives at an enormous bulk. King Charles' elm at Hampton Court measures 38 feet in circumference, at the height of 8 feet from the ground. The Wych elm at Field, Staffordshire, is 25 feet in girth.

The Chestnut, *Fagus castanea* (called Spanish, or sweet chestnut), is a very valuable timber tree, its wood being equally durable with that of oak. It was much used for building purposes in former times, both in this country and on the Continent, but its cultivation has been too much neglected of late in England. Chestnut timber may be seen in a state of perfect preservation in many parts of ancient ecclesiastical buildings, Pugin having specially distinguished it by name in the engravings of some of his works.

This tree, as well as the beech, appears to suffer less than any other of the timber trees from being planted in a moist sandy soil; but as the roots of the chestnut extend far downwards, they require a proportionate depth of soil. It grows with frequent twists and contortions of the stem, which, while it adds to its picturesqueness for ornamental purposes, certainly detracts from its value as a timber tree. Some of the largest chestnuts in Europe are found on the flanks of Mount Etna. The largest known in this country is at Torthworth in Gloucestershire. As their shade is detrimental to other trees, they should either be planted in clumps by themselves, or be given full room to spread. When the timber of the chestnut has been some time in use for roofs or joinery, it is difficult to distinguish it from oak.

The Beech, *Fagus*, is a timber that easily adapts itself to, and flourishes in, almost any soil. Even among rocks, its roots will, like those of firs and larches, insinuate themselves into the smallest fissures, and find means to extract sufficient nourishment to produce a useful timber. Beech timber, when used shortly after being felled, and for works where it will always remain in a damp state, is a long-enduring wood. It is largely applied in the mercantile navy for the lower planks of the bottoms of ships. The best variety has its wood of a yellow tinge. It is much used for making cheap furniture; also by railway contractors and others for temporary purposes, and by coopers. The symmetrical shape of the beech, and its bright glossy leaves, render this tree highly ornamental in the park or shrubbery, and the varying hues which its leaves assume as the autumn approaches are a great additional recommendation. As no tree suffers more from injudicious pruning of the roots or branches than the beech, it is better raised from seed in the situation it is intended permanently to occupy.

The Ash, *Fraxinus Excelsior*, will also accommodate itself to all soils. It will grow in marshy grounds, and in arid land, in deep or in shallow soil. The value of its wood for general purposes is second only to the oak in the list of British timber trees. The ash timber from very poor soils is brittle, wanting the elasticity which is the valuable peculiarity of this wood. It is a very useful timber for carts and implements of husbandry, for machinery, for tools of almost all trades, and it supplies oars to our shipping. When planted in a genial situation, it attains to a very great size, specimens being sometimes found which measure 30 feet in circumference, and 100 feet in height.

We have hitherto confined our remarks to the hard-wood trees, without noticing the numerous Firs which are so valuable to us. Their timber is admirably adapted by its manner of growth, its lightness, and strength, to supply our navies with masts and spars; while from its comparatively small cost, and the ease with which it is worked, it is used very largely for all purposes of building. Indeed, it is questionable whether fir is not more generally useful to us than any other species of timber. Du Hamel, in his treatise *Du Transport et de la conservation des Bois*, has drawn a distinction between firs and pines, although it is usual to designate the timber of both as fir timber. Pines, he says, have the leaves thready and slender, growing in clusters from the same leaf-stalk, while firs have straight leaves, each growing separate, but many growing on the same leaf-stalk like the teeth of a comb. Trees of the pine tribe have one principal root growing straight down like a carrot, with few fibres, while the roots of the fir are more lateral and superficial. The pines grow with their trunks much less tapering towards their tops than the firs; they are, therefore, from shape, more adapted for masts than firs. Their wood is also more resinous, and the resin is of a more glutinous nature, and therefore less easily evaporated. This quality enables the timber to resist better the absorption of water or moisture. The pine is more durable than the fir, and its fracture is, even when partially decayed, much more fibrous, and takes place with more previous warning. The timber of the pine, when healthy, is close-grained, even-textured, and of a bright yellow colour. The fir, although frequently little inferior in appearance in other respects, is always of a much paler shade of colour. The most valuable of all the varieties of fir timber is that which is called Riga Fir. It is the red-wood pine of the north of Europe, the Pinus Silvestris, which, although spread over a very large portion of the globe, appears to flourish in its greatest perfection in the forests of Lithuania and Poland, where the cold is severe and the soil generous. Riga fir is not only extremely flexible and elastic, but is by far the most durable of all the pine timbers; and as long as it could be procured of sufficient size, it was generally used in the royal navy, not only for topmasts, but also to build the lower or standard masts. At present, from the difficulty of procuring large sticks, the use of it is confined to topsail-yards and the smaller description of spars.

The American continent also produces this red pine timber of good quality, although much inferior to that of the north of Europe. It is imported from Canada and from Virginia. The Canadian red pine is of small size, seldom exceeding 14 hands. The Virginian pine is large, sticks of 24 and 25 inches in diameter not being uncommon. It is a resinous and flexible wood; but the sticks are more subject than the Canadian red pine to the defect of large knots, which, from not being firmly united to the surrounding timber (technically, "well-collared"), injure its value. The red pine thrives extremely well in Scotland, where it is called Scotch fir, but is not equal in quality to that imported from the north of Europe. The French dockyards are supplied with mast-timber from the red pine of the Pyrenees and of the island of Corsica, but neither of these is of first-rate quality. Indeed, a climate of low temperature appears to be essential to the growth of superior fir timber. The firs on the northern sides of hills and mountains, in all temperate climates, thrive better than those growing on the southern slope; and even the timber of the northern side of an exposed fir-tree is much superior to that of its southern side.

Yellow Pine, the Pinus Strobus, which is imported from Canada, is the principal timber now available for large masts and yards, and is very generally used both in the royal and mercantile navies, as well as for building purposes. It has neither the flexibility nor the elasticity of the red pine, nor is it so durable, but it is much lighter. Its great recommendations are its large size and its comparatively small cost. Sticks of this timber run from 16 to 27 or 28 inches in diameter; and for bow-sprits they are sometimes received in the royal yards as large as 29 and 30 inches in diameter; but sticks of these large dimensions are becoming very scarce. This timber grows also in Great Britain, where it was first introduced by an Earl of Weymouth, whence it is called the Weymouth pine; but it does not appear to thrive well in this climate.

The Spruce Fir, Pinus Abies, grows in Scotland, Norway, and other northern countries. It is very generally used in the mercantile navy for yards and top-masts, and also in the royal navy for the smaller description of spars and boats' masts. They are tough, close-grained, and elastic, but are very full of large knots; and care is therefore required in selecting them. The timber also is soft and far from durable, it having very little appearance of resin. The Norwegian spruce grows frequently to a large size.

Cedar, Pinus Cedrus, would be among the most valuable of all timber trees, were it sufficiently common to be available for building purposes. It is almost indestructible from time, and no insects will ever attack it. It thrives well in this climate, but hitherto has only been planted either as an object of curiosity or of ornament. It requires a more generous soil than any other of the tribe of pines, and is considered to be a timber of very slow growth. Pitch-pine is also a very valuable timber for building purposes, but it is too heavy for spars.

Fir sticks, the Riga-hand-masts especially, are very liable to have serious defects in them, which it is often impossible to discover until the stick is worked. They are technically called "upsets." The grain appears to be partly separated, so that a shaving from the stick at that place would bend to a sharp angle at the upset, as if partly broken. There always appears to be a greater or less accumulation of the turpentine about the injury, as if it had originally exuded at the wound, and become congealed around it. These defects are most frequently found in the smaller sticks, those especially that are more resinous and knotty than others; and they sometimes are so numerous as to extend, at very short distances apart, for a great portion of the length of the stick. Mr Craddock, who long superintended the mast-making at Portsmouth dock-yard, considers them to be the effect of violent winds on the more exposed trees of a forest. He finds this opinion on the facts that they are most common in the most flexible timber; that they are not perceived in sticks of large diameter; and that in the firs of little flexibility, as the yellow pine, they are seldom or never found; although the sticks of this fir, from being cut in every variety of direction, to form the components of made-masts, are more searched than any other. The Cowdee, a New Zealand timber, lately introduced both in the royal and mercantile navies, is, he says, much subject to this defect; and he has observed it once in a poon topmast. The defect seldom or never appears in the outer layers of the timber, but only after some of these have been removed by the axe, and the older timber laid bare of the sap-wood.

The sap-wood in all fir timber is useless, and very generally there is a large proportion of it in comparison to the quantity of heart-wood. It is rather a curious fact, that there appears to be a difference between the pines and the generality of the hard-wood timber in this, that a small proportion of sap-wood in fir is indicative of the inferiority of the timber. Thus the red pine of Scotland has fewer layers of sap-wood than either the red pine of Canada or of the Baltic. As a general remark, it may be stated, that the greater the quantity of sap-wood there is about a tree of any description of fir timber, the better will be the quality of the "spine," which is the technical name given to the mature wood.

The Cowdee, which is now largely imported into this country, is a close and even-grained timber, almost entirely free from knots. It grows to so large a size as to be available for the topmasts and other principal spars of the largest classes of vessels; but from its want of elasticity, and its liability to warp and rend, it is not so suitable for small conversions. It varies greatly in its quality, even so much as often to be of different colours, grain, and texture, in the same stick. It is about the same average weight as Virginia red pine.

Larch, Pinus Larix, formerly unknown in Great Britain, has, within the last century, been very extensively planted. The first plantations of it were made on the vast estates of the Duke of Atholl, in the Highlands of Scotland. The following account, which is extracted from Knowles On Preserving the Navy, was, as the author of that work states, furnished to him by the late duke, and it contains, consequently, the results of the longest experience as to the growth of larch timber in Britain which can be obtained. The account is interesting, because plantations of larch are becoming very numerous, as they are found to be very profitable. The returns from a larch plantation during the time the trees are arriving at their full growth, are estimated to be at least double what they would have been from an equal plantation of any other timber. "Seedlings of larch were probably first brought into Scotland in the year 1738 by Mr Menzies; but it has been asserted by some, that they were introduced into that part of this country in 1734 by Lord Kames. Some were left at Dunkeld, and some at Blair-Athole, by the former gentleman; and Timber being exotic plants, were placed by the gardeners in greenhouses. Not thriving in those situations, they were planted in the pleasure-grounds, where they grew luxuriantly. When the present duke succeeded to the titles and estates (in 1774), there was a considerable number of trees in a thriving state; and on a general survey of his estates in 1783, there were found to be 900 Scottish acres of plantation, 600 of which were of larch; since which time his grace has planted extensively every year, and in the spring of 1820, 10,820 Scottish, or about 12,984 English acres, were covered with trees. The different species were:

| Species | Scottish Acres | |--------------------------|----------------| | Oak | 800 | | Scottish firs | 1500 | | Spruce firs | 500 | | Mixed plantations in the pleasure-grounds | 200 | | Birch | 200 | | Larch | 7620 |

10,820

"The larch thrives in very exposed situations. The lower range of the Grampian Hills, which extends to Dunkeld, are at an altitude there of from 1000 to 1700 feet above the level of the sea. The larch-trees are planted as high as 1200 feet up these hills, and grow exceedingly well; a situation where the hardy Scottish firs cannot rear their heads. The spruce fir, however, thrives equally well as the larch on high and exposed hills. The growth of the larch-trees is very rapid, and Scottish fir of the same age will measure only half the quantity; and so much is the wood esteemed in Scotland, that while the former is worth 2s. 6d. per cubic foot, the latter brings only 1s. 3d.

The following account of a larch-tree, planted in the year 1738, and measured February 1819, will give some notion of its growth:—1 foot above the ground, girth 17 feet 8 inches; 2 feet, 14 feet 6 inches; 3 feet, 12 feet 7 inches; 5 feet, 11 feet 5 inches; 10 feet, 10 feet 4 inches; 20 feet, 9 feet 7 inches; 50 feet, 6 feet 3 inches; 70 feet, 3 feet 2 inches; 75 feet, 1 foot 10 inches.

"The top was fifteen feet in height, making the whole height 90 feet; and the tree measured 300 feet, or 6 loads, in cubical contents. The white and red larch-trees are those chiefly planted. The duke has made trial of the black or American, and also of the Russian larch, but has found that they do not thrive well. The timber in question has been used for many years in Scotland for almost all local purposes, such as posts, rails, mill-wheels, fishing and ferry boats; and in all these situations has been found to be very durable. The author has seen part of a ferry-boat twenty-three years old, which remained very sound, and the iron nails driven into it as perfect as when they first came from the forge. This, perhaps, was occasioned by their being constantly covered with an insoluble varnish, with which the larch abounds. One of the qualities of larch for building merchant-ships is its great lightness, a cubic foot, weighing, when seasoned (which it does rapidly), only 34 lb. Although it is not so strong as many sorts of wood, it has great resilience. Cabinet-work of great beauty has been made from larch; it polishes well, and when seasoned is not found to warp or shrink. A most important fact in agriculture has arisen from planting larch-trees on rocky ground; the vegetable compost formed thereon by the falling of the leaves has been the cause of producing herbage for feeding cattle, and made that land, which, on the average, did not formerly bring more than 8d. or 9d. per acre, now to be worth from 12s. to 14s. per acre annually."

Larch timber, although so generally planted, and so generally thriving, requires considerable attention in the selection of proper soil for it. It is very subject to a heart-rot, which seizes on the roots, and rapidly proceeds up the centre of the stem of the plant, the latter swelling considerably for several feet above the surface of the ground. Larch cannot bear a cold damp soil, or any stagnation of water, or even the moisture of the rich vegetable moulds. Nor will it thrive in the light sandy soils; for although it dislikes marshy stagnant waters, its roots require to be preserved from the droughts of summer. Sandy and gravelly soils, if situated so as to receive from declivities the moisture percolating through them, will produce excellent larch timber; as will also the sides of rocky hills and mountains, in which no moisture can stagnate, and into the fissures and clefts of which the roots easily penetrate and find ample nourishment. Larch-trees attain to a very great height. In some of the public buildings of Venice there are said to be single-pieced beams of larch which are 120 feet in length. It must be very durable, for it is almost the only wood which was used in the palaces and public buildings of that city.

The timber imported from Canada under the name of American hackmatack is believed to be identical with the Scottish timber-larch. The timber of America in general is very inferior to that grown in the north of Europe, being much softer in its nature, not nearly so durable, and more liable to the dry-rot. American timber is therefore seldom used in ship-building, except for deck-deals, and but sparingly also in the construction of first-class houses.

In consequence of the immense consumption of timber Foreign for the maintenance of our fleets, we are obliged to import timber much from abroad. We obtain oak of excellent quality Oak for planking from Poland and the shores of the Baltic; while from Italy, and from both sides of the Adriatic, sided timber and plank are imported in large quantities. American oak and rock-elm are both valuable timbers, and are now coming into very general use in this country, being introduced in considerable quantity. The former is used by cabinet-makers and carriage-builders, principally on account of its great size, uniform texture, straightness of grain, and little tendency to warp. Its specific gravity is somewhat less than that of English oak. Rock-elm is becoming Rock-elm much used for engineering purposes. It is remarkably uniform in texture and growth, and perfectly straight and free from knots. Its great length and uniform siding render it extremely useful for longitudinal ties, piles, and other purposes, which require great length, combined with uniformity in dimension. For example, a baulk of rock-elm, 54 feet long, was found to taper only 1\(\frac{1}{2}\) inch, and when slabbbed, was 12\(\frac{1}{2}\) inches square in section, and 51\(\frac{1}{2}\) feet long. A specimen cut from this baulk weighed 50 lb. per cube foot, its specific gravity being equal to that of English oak.

One of the most largely imported woods of tropical Teak countries, and one of the most valuable, is teak. It grows to an enormous size, is particularly straight and free from knots, and has the peculiar property of resisting the attacks of insects. It possesses greater toughness than almost any other wood of equal weight, and is little liable to dry-rot or other disease. The great durability of teak is to be attributed to the large amount of oleaginous matter contained in this timber. Like all other woods, it varies much in quality, according to the locality where it is grown. The finest teak comes from Malabar; then follow the importations from Travancore, Ceylon, Java, the Malayan Peninsula, from Pegu and Moulmein. The two last descriptions of teak are very inferior to the Malabar variety, being comparatively coarse, porous, and open-grained; but this inferiority is believed to be due rather to the low swampy locality from which it is cut for the foreign market, than to any inherent bad quality of the timber. Its weight, when moderately seasoned, may be stated to be 42 lb. per cubic foot, while the weight of Malabar teak, on an average, is from 45 to 52 lbs. per cubic foot. The forests of Tonga and Irrawaddy supply the whole of the... Timber. Pegu teak. That of the Tonga forests is of the best quality, the country being high, and not flooded during the rainy season; whereas the forests of the Irrawaddy are always in a swampy state, and are part of the year covered with water sufficient to allow of the trees being floated from where they are felled. The Birmans are in the habit of tapping the teak-trees, particularly those which are straight grown, to extract a varnish or oil, which is highly prized by them, and used chiefly for protecting their pagodas or temples from the weather, for which purpose it is very effectual. These edifices are built entirely of untap teak, as the Birmans consider the timber to be much injured, both in its strength and its durability, by being deprived of this oil. The principal parts of these temples are sunk in the ground, and although so fixed, the timber remains perfectly sound, notwithstanding many of them have stood nearly a century.

Inferior as the Pegu and Moulmein teak is to the Malabar or Bombay teak, it is still preferable to the saul, which is now imported to this country in considerable quantity. This is a hard heavy wood, growing in Behar, Oude, and the inexhaustible forests skirting the hills that form the northern boundaries of Bengal. It varies much in quality, the best timber being found occupying the rocky ground at the foot of the hills, while that grown in the alluvial plains is very inferior. As a rule, it deteriorates in quality the further it is produced to the westward. Sauls of large dimensions are now becoming very scarce, as the whole of the forests within a reasonable distance of the navigable streams are quite exhausted; but it is hoped, that as the Indian railways extend into the interior of the country, a further supply of valuable timber will thus become available for exportation. The best description of saul, if well seasoned, may be classed, in point of durability, with the best sort of African timber, now so extensively used by ship-builders in this country. The greatest care is necessary in the selection of saul for immediate use, on account of its requiring a long time to season, and it must not be employed in ship-building for any part exposed to the sun, as it shrinks very much. Saul is used for the frame, beams, shelf-pieces, breast-hooks, and inside planking of ships built in Calcutta.

The principal woods used in India for ship-building are, besides teak and saul, sissoo, jarrol, poon, and toon, teak being the most durable of them all. Indeed, from the great length of time which several vessels built of Malabar teak have lasted (from thirty to fifty years, and in some particular instances nearly a century), this may be said to be the most valuable timber for ship-building purposes yet known. It is, however, like every other kind of wood, liable to premature decay, if not properly and gradually seasoned by exposure to a moderate current of air, after being felled. Java teak is of very superior quality, little if at all inferior to that from the Malabar coast, and is extensively used for ship-building at Calcutta. "The teak which is grown on high, dry, and open land," says Mr Leonard Wray, in a paper read to the Society of Arts, "is generally of a fine quality, close and compact, and abounding in a mild oil, which exerts no injurious effect upon the iron bolts which may be driven into it. That grown in the dense forests of the wet, low-lying alluvials, on the contrary, is lighter, coarser grained, and contains an acid oil, which not only affects iron very materially, but even, to a certain extent, poisons and inflames the hand which has been pierced by its splinters."

As a test of the durability of a Calcutta-built ship, we may cite the Hastings, 74 gun frigate, built at Calcutta in 1818. The hull is composed of saul, sissoo, Pegu and Java teak, all of the best kind. So great was the expense incurred in the building of this ship, that when completed, the account, after giving credit for her freight, exhibited the cost of the hull for sea, 1,163,754 Sicca rupees, or, ten rupees to the pound, L.116,375 sterling. It is usual in Calcutta-built ships to convert the frame, with the knees, Durability breast-hooks, &c., from sissoo timber; the beams and inside of Indian planking being of saul, and the bottoms, wales, topsides, woods, decks, keels, stem, and stern-post, of the Pegu teak.

Mahogany is the produce of America and the West Indies, Mahogany, being principally imported from Honduras and Campeachy. That imported from the islands is called Spanish mahogany. It differs very much in quality according to soil and locality, the weight of a cubic foot varying from about 53 lbs. to 35 lbs.

Although mahogany may be stated to be a durable and valuable timber both for ship-building and general purposes, it varies so very much in texture and quality, that the utmost care and judgment are necessary in its selection. There are many well authenticated instances of the extraordinary strength and durability of ships built almost exclusively of mahogany, the most famous being that of the Spanish 80 gun ship Gibraltar, captured by the English in 1757, and broken up at the age of 100 years, when all her timbers were found to be perfectly sound. This, however, only proves the excellent quality of carefully selected Spanish mahogany (the Gibraltar having been built at Havana), it being equally well known that light, porous, "swamp mahogany," or indeed any of inferior quality, is highly treacherous and unsafe when employed for the timbering of a ship. It is an error to suppose that all Honduras mahogany is light and spongy, the best quality of this timber being as heavy as Malabar teak or English oak, and only the inferior qualities of mahogany being so very light and buoyant. Mahogany is highly prized for the paddle-beams and deck-beams of steam-vessels, in positions where these are exposed to the moist heat of the engine-room, which is very destructive to most other species of timber.

According to "Lloyd's" classification of timbers, those in the first class are the following only:—English oak, tion of African oak, the live oak of America, the morra and green-timbers at heart of British Guiana, the teak and saul of India, and Lloyd's the iron bark of Australia. These are all close-grained, compact woods, hard, heavy, strong, and durable, being more or less impregnated with certain oily, resinous, or astringent matters. Mahogany of hard texture, though treated as a second-rate timber, is so far admitted in the construction of A 1 ships, as to include beams and hooks, knees, rudder, and windlass, main-pieces, outside planking to light mark, and the whole of the inside planking.

Greenheart, the produce of British Guiana, is a very valuable timber. It is a hard, close-grained wood, containing a considerable quantity of oil, like teak. Its specific gravity is about equal to that of African oak, but it is decidedly superior to it in strength, toughness, and durability. These, however, are not its chief advantages, its great value consisting in its complete exemption from the attacks of marine worms. It is therefore an excellent timber for sluice-gates, piles, and all marine engineering works, which would be exposed to their ravages. It is imported in logs of from 12 to 16 inches square, and from 20 to 40 feet in length. It has been used in some instances for the planking of ships. Mr Wray, from whose interesting paper "On Timber for Ship-Building" we have already quoted, says, that greenheart is very abundant within 100 miles of the coast of British Guiana, and can be had almost to any extent.

Another excellent timber of British Guiana, still more Morra, abundant than the last, is morra. This tree grows to a very great size, often attaining the height of 100 to 150 feet, the lowest branches being 60 feet from the ground. The wood is extremely tough, close, and cross-grained, which properties make it difficult to split, and render it peculiarly applicable to ship-building purposes. It is stated to be little subject to dry-rot. The other British possessions from which we might readily draw a supply of excellent timber are Assam and Tenasserim in the north of India, our settlements in the Straits of Malacca, and Western Australia. From the latter country we have the iron-bark, a first-class timber; the tuart, the jarrah, the blue-gum, and the morell. The tuart is a noble timber tree, growing in tolerable abundance on the coast. Planks are sometimes obtained of it 10 feet wide; and it is said to be peculiarly adapted to the building of ships of war, as it is difficult to split, and not liable to splinter. In colour it is pale-yellow, or white. Its timber is remarkably cross-grained, hard, and tough, and very strong and durable.

The blue-gum is also an enormous tree, "sometimes," says Mr Wray, "yielding planks 14 feet wide, and more than 120 feet long." The jarrah of Western Australia is frequently confounded with mahogany, to which some species of it bear a certain resemblance. Mr Reveley, a government engineer in Australia, thus describes the jarrah:—"First, in colour, there is every variety of shade, from almost crimson to reddish brown, and pale brown, inclining to white. In the second place, as to grain, there is almost every variety, from the perfectly straight fibre to every species of curl, including the zebra and satin specimens. The length of the stem of this tree, taking the average, may be 65 feet (many being much longer), without a branch or a knot in all that length, and very nearly equal in size all the way up. It is not attacked by insects of any kind, nor has it any tendency to dry-rot, and is scarcely affected in any way by damp or moisture." There are forests of this wood in Western Australia of more than 4 miles in depth, and which are known to extend for a length of 150 miles. Here, then, is timber enough to maintain our navy for a hundred years to come, if we would only avail ourselves of the resources of this valuable colony, and encourage the exportation of its timber, by providing a ready means of access to a shipping port.

We shall now mention a few other species of timber trees, of minor importance to the preceding, but still useful for many purposes of construction.

Acacia, is of small dimensions, seldom exceeding two feet in diameter; but when used in house-carpetry is very durable. It is harder, tougher, and more elastic than the best oak. It is a valuable timber for tree-nails for ship-building; also, for posts and rails for fences, in which capacity it is very enduring.

Alder.—The wood of this tree lasts a long time under water, which renders it valuable for piles, water-pipes, &c. It has a close texture, a fine colour, and works well under the plane, which makes it a favourite with the cabinet-maker. The best charcoal for gunpowder is made from this wood. When burned in the open air, 1000 lbs. of the ashes yield 65 lbs. of potash.

Birch.—This wood is hard, but not very durable. It is chiefly used for making cheap furniture, and for firewood.

Box is a valuable wood, being very close-grained, hard, and heavy, and cuts very clean under the chisel or graving-tool, being therefore used almost exclusively by the wood-engraver. Being susceptible of a fine polish, it is much used by the turner, mathematical instrument-maker, &c. It is also very durable.

Cedar (Cedrus pinus) grows to a great size; the timber is resinous, of a reddish-white colour, light and spongy in its texture, easily worked, but apt to shrink and warp if great attention be not paid to the seasoning. It was much valued by the ancients for its durability and preservative properties. The wood is odoriferous, and admirably adapted for joiner-work, being light and easily worked. Although a resinous wood, it contains but a small quantity of that substance. It resists the attacks of insects.

Cedar, Indian (Cedrus deodara), is also a very large tree. The wood is very compact, highly impregnated with resin, and possessed of a hard and fine grain. Its durability when exposed to the weather is very great, some bridges constructed of it in India having lasted for five hundred years. It is much used by the Hindoos in their buildings.

Chestnut (Castanea) has been already mentioned as a very excellent timber for building purposes. The Horse Chestnut, on the other hand, is a soft, inferior wood of but little strength or durability. It resists moisture, however, and may be advantageously used for water-pipes under ground.

Cypress is a fine-grained wood, remarkable for its great durability, and its freedom from injury by worms or insects. Owing to this property, it was employed in Egypt for mummy-cases.

Hornbeam is a hard, heavy, tenacious wood, very close grained. It is much used for cogs of wheels and other engineering purposes, where the material is exposed to friction.

Lignum vitae is a very hard, dense wood, much used by millwrights and turners; its chief use, however, is for the sheaves of blocks. It is also employed by the engineer for lining the sockets of shafts, which are found to revolve in it with little friction and wear.

Lime, though a highly ornamental tree, and growing to a great size, is not of much value for its timber, which is soft and light, and deficient in strength and durability. Being close grained and smooth in its texture, however, it is well adapted for carving and cabinet-work.

Maple is a clean, white wood, prized for its lightness, and is used by the turner for making dishes, bowls, and trenchers; and by the joiner for common furniture. As it is not liable to warp or split, it is readily stained to imitate mahogany and other woods.

Plane.—The wood of this tree much resembles the beech. It is used by the joiner and cabinet-maker, but is not remarkable for strength or endurance. It keeps best under water, and is used in America for quays and other marine works.

Poplar.—The wood of this tree (of which several kinds are grown in this country) is much used by builders for floors, especially, as it does not easily split by driving nails into it, and it has the property of not readily catching fire. When used for this purpose, however, it requires from two to three years' seasoning, as it shrinks much in drying.

Sycamore, when kept dry, is durable; but is readily attacked by the worm. It is a species of maple, and is possessed of similar qualities.

Walnut is one of the most valuable of English timbers. The wood is solid and compact, easy to work, not liable to crack or warp, and handsome in appearance; it is therefore much used for the better class of furniture. The screws of presses and gun-stocks are generally made of it. The black Virginia walnut is the most prized. It prefers hilly, calcareous soils.

Willow is a soft, smooth, light wood, of little value; but, if kept dry, it will last a long time in situations where much strength is not required.

Yew was principally used of old for the making of bows, and is now a favourite wood with turners from the smoothness and toughness of its grain, and from its taking a high polish. It sometimes attains an extraordinary bulk. At Gresford, near Wrexham, there is a yew 29 feet in circumference at a little distance below the branches; and in Dibdin churchyard, New Forest, there is a yew-tree measuring 30 feet in girth at the ground; while others, of large size, occur at Ilseley, Hampton Court, Dorly-in-the-Dale, Tisbury, and other places. When found growing in churchyards, they may be generally reckoned as coeval with the church itself.

As the strength of timber has been already treated of in the articles, Strength of Materials, and Ship-Building, we have little to add here upon this important subject. It may be observed, however, that the weight or density of a strength of timber is in general a sure index to its strength, the densest wood being at the same time the strongest and the most durable. The oak, as well as all other timbers, varies in its specific gravity according to the soil which produces it; the density mainly depending upon the length of time occupied in the formation of the wood. Those trees which grow fast from being located on moist, sandy soils, never produce such strong timber as others of slower growth. It has been found by experiment, that the bottom part of the trunk, with the corresponding branches, is denser and stronger than the upper part of the same tree. Those trees which are suffered to complete their full term of growth before being cut down, have their heart-wood throughout of the same weight and strength, taking a cross section of the trunk at any one place, whilst those that are felled prematurely are found to possess these qualifications in the central portion of the wood only, which is then considerably harder than that immediately surrounding the sapwood. In trees which have been overgrown, on the other hand, the central portion of the wood is the weakest, the process of natural decay always commencing in the heart of the tree. It is a common thing to see the heart of some fine tree (blown over by the wind, perhaps), which, to an untrained eye, looks perfectly sound and flourishing, to be already disintegrated by the spreading filaments of dry-rot, which have attacked it so soon as its vigour began to flag.

The age at which oak timber is at its prime, is generally supposed to be from eighty to a hundred years, although this depends, as we have before explained, upon the nature of the soil on which it is grown. The weight of good oak timber is about 60 lbs. in the green state; and, when seasoned, about 50 lbs. If the seasoning is carried beyond this by artificial desiccation, the strength of the timber is impaired.

The decay of wood by the growth of fungae, denominated dry-rot, may be traced to the putrifying of the sap, when this has been left within the pores of the timber in the same condition as it exists in the living tree. The various means which are employed to arrest this destructive fermentation are, either to wash out the sap by long soaking in water, aided by the action of the sun; to dry up the sap, either naturally by exposure to the sun and wind, or artificially by baking, or by heated currents of air; or else by injecting into the pores of the wood some metallic salt to combine with the albumen and render it insoluble, or some antiseptic substance to preserve the vegetable tissue. The processes of natural seasoning and artificial desiccation, being those most in use for the preservation of ship-timber, will be found amply described in the article Shipbuilding; also, the best mode of creosoting, although the latter process, from the increased inflammability and the strong smell it imparts to timber, is scarcely applicable to the building either of ships or houses. For the preservation of railway-sleepers, and other wood-work out of doors, which is not particularly liable to danger from fire, the creosoting process has been proved to be most valuable. Its efficiency depends, in a great measure, upon the mode of operation, and the quantity of creosote injected into the timber, which should be done under pressure in a closed cylinder. The process is most applicable to fir and other soft woods, which should imbibe, at least, 7 lbs. of the creosote oil per cubic foot, oak imbibing not more than 2 or 3 lbs., even under a pressure of 120 lbs. per square inch. This substance seems to act, firstly, by coagulating the albumen; secondly, by furnishing a water-proof covering to the fibre of the wood; and, thirdly, by preventing the putrefaction of the sap by its antiseptic properties.

The various processes for the preservation of timber by the absorption of metallic salts, have all more or less failed in practice, and are now very generally abandoned. These timber are known by the names of the inventors, as Kyan's, Margary's, Burnett's, and Payne's processes. The object sought by each of the three first of these methods was that of coagulating the albumen in the capillary tubes of the metallic timber, and thus prevent, or retard, the putrefaction of the sap. Kyan used chloride of mercury for this purpose, dissolving, at first, 1 lb. of the salt in 4 gallons of water; but process as it was found that the wood absorbed about 6 or 7 lbs. of this costly salt per load, more water was added to lessen the expense, until the solution became so weak as, in a great measure, to lose its effect. This process has, therefore, been entirely abandoned. The salt employed by Margary was sulphate of copper, which, being much cheaper than chloride of mercury, could be used as a stronger solution. Its efficacy, however, has proved doubtful in many cases, while in not a few instances it has failed altogether. Better than either of the preceding is Sir William Burnett's plan of injecting a solution of chloride of zinc, in the proportion of about 1 lb. of the salt to 4 or 5 gallons of water. This process is still in use, and has certainly proved beneficial in a great many cases, but it cannot always be relied upon. Payne's process consisted in the successive injection of two substances in solution—the first, a metallic or earthy solution, and the second a decomposing fluid—the consequence being that the capillary tubes of the timber became filled with an insoluble substance. The process of Superficial creosoting timber, already referred to, was first patented by Mr Bethell in the year 1848. One great advantage of creosoted timber is, that it perfectly resists the attacks of marine worms and insects, as well as the white ant of India, which is more than can be said for timber prepared with solutions of metallic salts. Even that prepared with corrosive sublimate (as in Kyan's patent) has no immunity in this respect, the albumen appearing to neutralize the poisonous property of the salt.

For ship-building purposes such chemically prepared, or Artificially "salted," timber is scarcely to be recommended, as it attracts much moisture, and is very destructive to the metal fastenings. Empyreumatic oils and resinous solutions, although these certainly render the wood impervious to moisture, and preserve the iron or metal bolts from oxidation, are still very objectionable from the increased inflammability which they impart to the structure. The time necessarily required in preparing the wood with the preservative substance is also a great drawback to its employment in ship-building, where a delay of even two or three days, more especially in repairing, is often of serious consequence; and it should be remembered, the timber must be operated upon after it has been shaped or "converted." Timber may be very perfectly preserved from subsequent decay by long submersion in shallow salt water, or, which timber is still better, in salt mud. When thus treated for a period of from ten to twenty years, the sap gets thoroughly washed out of the pores of the wood by the alternate absorption and expulsion of air or other gases, caused by successive variations of temperature. It need scarcely be hinted, however, that such a mode of procedure, though sometimes adopted in government dockyards, would be ruinously expensive to the private ship-builder.

Having pointed out the fatal objections generally attending the use of chemically-prepared timber for ships or houses, it remains to show what means can be employed (and that with tolerable certainty) for preserving the timber of these structures from premature decay. The means serving our command for this purpose are summed up in the timber, two words, "seasoning" and "ventilation;" namely, thorough seasoning or drying of the timber on shore, when this is practicable; but, by all means, good ventilation on board. If these well-known and universally approved principles were but carried out in an honest and common-sense fashion, we should hear but little of rotten gun-boats, or heavy repairs to frigates after a first commission. Though it is undoubtedly true that the closely-packed timbers and double planking of a vessel of war present great obstacles to a thorough ventilation of the bottom, much may still be done by conducting currents of air down into the hold, and between the timbers, by means of wind-sails, or, if necessary, by fans worked either by steam or hand, and by so arranging the internal accommodation that there may be as little stagnation of air as possible. However well seasoned and dry the timber may be when the ship is launched, it will rapidly absorb moisture from the damp atmosphere of the hold, unless evaporation from its surface be kept up by a forced circulation of air.

It is certainly unbecoming the scientific character of the age that ships built hurriedly and cheaply, and of very inferior timber, by what are contemptuously called "slop" builders, are known to resist the ravages of dry-rot much better than the expensively and elaborately-constructed ships of Her Majesty's dockyards; nay, more, that these same "slop-built" ships, even when constructed entirely of green timber (as they frequently are), will last longer than a government ship built with the best seasoned oak! The whole secret is, of course, the internal ventilation of the holds and frame of the ship. In a cheaply-built merchant-ship the timbers are spaced at some distance apart, and the ceiling planks are not placed so close together as hermetically to seal the spaces between the timbers, the consequence being that good ventilation is maintained amongst the planks and timbers of the bottom and sides. Even when such a ship is built of green wood, the circulation of air is generally sufficient to season the timber in its place and prevent its decay; for the dry-rot fungus will not thrive in an atmosphere less moist and stagnant than that of an underground cellar. The shrinkage of green timber in such a case would also conduce to its preservation by admitting the air between the ceiling planks.

These remarks are not intended to excuse the use of unseasoned timber in ship-building, a practice which should be resorted to only from dire necessity, but rather to show that if ships built of green timber can be preserved by what may be termed accidental ventilation, those built of seasoned timber should, _a fortiori_, be still more easily preserved by systematic ventilation. The action of heat in causing an upward current of air naturally suggests itself as a ready means of effecting this object on board ship. The dry-rot has been frequently arrested in a ship by thoroughly drying the timbers, holes having been previously cut in the ceiling planks to promote circulation. Yachts and other small vessels, when not in use, may be preserved from dry-rot by hauling them up out of the water in an exposed situation where the wind will get to them, keeping skylights and hatches open, and if a plank be removed from the bottom they will be all the safer. Should they be entirely closed up, on the other hand, the dry-rot will flourish within like mushrooms on a hot-bed.

Sap-wood should always be removed from the timbers and planks of a ship, as from its spongy texture and imperfect development, it is more liable to dry-rot than the sap-wood heart-wood (besides being much weaker); and when the should be dry-rot has once commenced either in a ship or a house, it removed is rapidly propagated by contagion. The process of seasoning timber quickly by a current of heated air will be found amply detailed in the article Ship-Building.

Timber is bought and sold by solid measure, according to the number of cubic feet in the tree or log. The measurement of timber is therefore the operation by which timber, these cubic contents are determined; that is, multiplying together the three dimensions, or the mean length, the breadth, and the depth, of each log. If the log should vary much in size in different parts, then the length, breadth, and depth of each of these parts must be multiplied together, and the contents of the log will be the sum of the products. When the log tapers, a mean breadth or depth is taken; the object in every case being to attain the most correct approximation to the contents of the log. In measuring rough logs, it is however usual to gird the log at the measuring place with a string, and then, folding the string into four equal parts, to assume this fourth part of the girth to be one side of the square area at the measuring place; which area, when multiplied by the length, will give the solid contents of the log. The arithmetical operation, simple as it is, is universally superseded by the more simple and far more correct plan of referring to published tables of contents, calculated for every foot in length of a log, and every quarter of an inch in the side of the square. Those most generally used for this purpose are in Hoppus's Practical Measurer.

In measuring standing timber, the length is taken as high as the tree will measure 24 inches in circumference, less than which measurement is not considered as timber. At half this height, the measurement for the mean girth of the timber in the stem of the tree is taken; one-fourth of this girth is assumed to be the side of the equivalent square area. The buyer has in general the option of choosing any spot between the butt-end and the half height of the stem as the girdling place. All branches, as far as they measure 24 inches in girth, are measured in with the tree as timber. An allowance, which varies according to circumstances, is generally deducted for the bark. In oak it is from about one-tenth to one-twelfth of the circumference at the girdling place; in other sorts of timber it is less. In all, however, this allowance depends much upon special agreement.

It is usual to speak of timber by the load, which means 50 cubic feet of squared timber, or 40 cubic feet of rough timber. A load of plank is dependent upon its thickness. Thus it will require 200 square feet of 3-inch plank to make the load of 50 cubic feet; therefore the load of plank is the number of square feet of its respective thickness, which is necessary to make the load of 50 cubic feet. Deals are measured, according to their thickness and lengths, by the hundred, reckoning 120 to the hundred.