imple bridge of the moveable sort might be formed, so as to move backwards and forwards in a straight line, like a waggon on a railway. Some rude bridges upon this principle are said to have been long in use in China.

BOATS.

Boats formed exclusively for canals are much longer and narrower than those which are also intended for rivers, or for river navigation alone. It is found, that when made of this shape, they are tracked with more ease or speed than when of a wider and shorter form; and they likewise occasion less injury to the sides of the canal. Indeed the proportions of the boats must always be regulated by the dimensions of the locks and bridges; and these have often been made of very reduced width, from considerations of economy in the construction. In the central districts of England, the boats are without masts. They are generally sharp at both ends, having no projecting stern, but being guarded by three rows of wrought-iron bands, which extend round the bows to the distance of twenty feet on each side, above and below the water line. The bottom is nearly flat, but they are generally encumbered with a keel, which is of no use in a canal but to require a greater depth of water. Keels sufficiently heavy, it is true, may act as ballast, but that would not compensate for the other inconvenience. Where very long boats would not have room to turn, several short ones are linked together in a string; one horse drawing these more easily than a single boat of great breadth, which, besides, might not have room to pass through the locks. The boats of the Mersey and Irwell Navigation Company are provided with masts and sails, such that they can coast round the whole island; and they are capable, too, of contending with the most boisterous weather. Their masts are made to strike by means of a forestay attached to two double-sheaved blocks, one of which is firmly fixed to the top of the stem; and the stay is heaved down by a windlass on the forepart of the deck. The boom extends no farther out than the after extremity of the rudder, and the stern is made nearly vertical. Vessels similar to these, especially in having a falling mast to pass under bridges, are much employed on the Thames and other rivers.

Oars, no doubt, in some shape or other, formed at an early period a means of propelling vessels on inland waters, and are still in use for that purpose. Sails, too, are employed on lakes and in the wider parts of rivers, if the current is moderate, with sufficient room for tacking; and during a favourable wind almost all vessels which may, on any account, be provided with sails, are in the habit of hoisting them when on a narrow river or canal. But in the latter cases the most usual method is to track or draw the vessels along by the power of men or horses travelling on the banks. The practice of men tracking boats is probably very ancient, and is still the mode in China and other barbarous or obscure places, where vast numbers of men continue to be thus employed. Nay, to come nearer home, it was even continued on the Thames and the Severn till near the end of last century, when proper towing paths and horses were, for the first time, introduced on these rivers, as they had been long before on canals.

But the most efficient power hitherto employed for propelling vessels, either in still water or against a moderate current in a large river, is that of steam, which has now come into general use for that purpose; though it certainly acts at a prodigious disadvantage, by re-acting against water which it is either leaving or which is moving from it,—a disadvantage, too, which augments with the rate of sailing. For this reason, and on account of the force which is wasted by the paddle-boards in entering and quitting the water with great velocity, and which waste also increases with the velocity of the paddles, it follows that the force of the steam-engine must be greatly increased, to occasion such an increase in the reaction of the paddles as shall urge the vessel with any considerably greater rapidity. Such seem to be some of the reasons why we often hear of a vessel being propelled by a power equal to that of 500 or 600 horses, while there is not the least probability that it is encountering a resistance of one fifth so much.

Of late years a great many experiments have been made on the trackage and resistance of canal-boats, particularly by Mr Palmer, Mr Macneill, and Mr Russell; but their results, though interesting, are very discordant. Mr Palmer makes the resistance as the cube of the velocity, which would be fatal altogether to anything in the shape of swift boats. Mr Macneill, again, makes the most advantageous velocity about nine or ten miles per hour, which is nearly what has been in use, and found to answer so well for several years with light boats carrying passengers on different canals, as we shall presently notice more particularly. But Mr Russell carries the most advantageous velocity very high, if indeed he gives it a limit; that, even granting his experiments to be perfectly correct, we have great doubts whether such velocities can ever be applicable to any practical purpose, at least of the nature of a long navigation.

Light boats for conveying passengers with a speed formerly unknown upon canals, were first introduced by Mr Houston, in June 1831, on the Glasgow and Paisley Canal. The following account of its success, after a two years' trial, is given by Mr Thomas Grahame, civil engineer, in his Letter to Canal Proprietors and Traders. "The ordinary speed for the conveyance of passengers on the Ardrossan Canal has, for nearly two years, been from nine to ten miles an hour; and although there are fourteen journeys along the canal per day at this rapid speed, its banks have sustained no injury. The boats are seventy feet in length, about five feet and a half broad, and, but for the extreme narrowness of the canal, might be made broader. They carry easily from seventy to eighty passengers; and, when required, can and have carried upwards of 110 passengers. The entire cost of a boat and fittings up is about L125. The hulls are formed of light iron plate and ribs, and the covering is of wood and light oiled cloth. They are more airy, light, and comfortable, than any coach. They permit the passengers to move about from the outer to the inner cabin; and the fares per mile are one penny in the first, and three farthings in the second cabin. The passengers are all carried under cover, having the privilege also of an uncovered space. These boats are drawn by two horses, the prices of which may be from L50 to L60 per pair, in stages of four miles in length, which are done in from twenty-two to twenty-five minutes, including stoppages to let out and take in passengers, each set of horses doing three or four stages alternately each day. In fact, the boats are drawn through this narrow and shallow canal at a velocity which many celebrated engineers had demonstrated, and which the public believed, to be impossible."

Swift boats have likewise been for several years in use on the Forth and Clyde Canal, the Edinburgh and Glas-

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1 A small boat closely covered in is by no means free from danger on a deep canal; for if by accident or mismanagement it were allowed to sink, it would be very apt to confine the inmates under water till they were drowned, especially as those who become frantic would prevent the more sober from escaping.

nion Canal, the Lancaster Canal, and on various others, with equal success, at least between locks, or wherever they are free from locks. There is, however, little reason to expect, as some seem to do, that any material increase of swiftness above that now described is likely ever to be effected with advantage on ordinary canals. Horses have already been pushed to their utmost speed; and were steam introduced, with all its machinery and apparatus, the weight would be so enormously augmented as to require a prodigious increase of moving power. But, on several other accounts, the ordinary canals, and almost everything connected with them, are totally unfit for a much greater velocity. Swifter boats would require canals to be interrupted by no locks, to have no contractions at tunnels and bridges, and to be incommodeed by no barges or other slow and heavy craft, which cannot instantly be cleared out of the way. Drawbridges would be attended with a similar inconvenience. The slightest covering, even of broken ice, would occasion a serious resistance; whilst intense frost, which has no effect upon railways, arrests boats altogether. The Americans, it is true, pretend to have greatly outstripped us in swiftness; but it is fully as easy to read some of their statements on this head as to give them entire credit. There can be no question that it is easier to propel a boat more speedily along a great river like the Hudson, than in our narrow and shallow canals, where much time is lost in passing through the locks, or great inconvenience is experienced in conveying the cargo from one boat to another, past the locks.

The swiftest boat would take almost the same time to pass through a lock as the most tardy and unwieldy barge; and it would be difficult, and even hazardous, from the risk of striking against the ends of the building, to force it swiftly through, and especially to make it enter a narrow tunnel, or the narrow contractions at bridges or aqueducts. On these accounts, and the perpetual risk of running foul of other craft, the piloting of a very swift boat is a task with which few could be intrusted, or rather for which no one is competent. These, however, are difficulties and dangers with which railways have not necessarily any thing to do; because the railway itself acts as the most perfect pilot. In short, to think, as some do, that, at this age of the world, canals can ever be brought to compete with railways in point of swiftness, is a project which cannot be listened to by any disinterested person who is sufficiently informed on such subjects.

On the other hand, although the kind of traffic on which canals have hitherto depended principally for their support is not likely to be withdrawn from them by the competition of railways, as appears from the canal business between Liverpool and Manchester having increased since the railway came into operation, yet it is not so easy to quiet the fears of those who are more immediately concerned; and those who do give way to such fears put themselves in the way of being ridiculously imposed upon. Accordingly, a few years ago, a pamphlet was most industriously circulated throughout England, with the view of setting forth the great superiority of canals over railways, and also of showing what a most ruinous speculation the Liverpool and Manchester Railway had been. Such assertions, however, met with a speedy refutation; and, in some discussion which arose on the subject, the author of the pamphlet let out that he had been hired on purpose, and also, what is curious, that his reward was not simply derived from proprietors of coaches and canals, but that one of our great seminaries of religion and learning had liberally afforded him its share of support.

The following is a list of works to which we have either been indebted in drawing up the preceding pages, or at least from which much farther information may still be obtained; though these, after all, form but a small proportion of the works which treat more or less on subjects relating to inland navigation:—Belidor, Architecture Hydraulique; Lalande, Traité des Canaux de Navigation; Frisi, de Canali Navigabili; Phillips' History of Inland Navigation; Fulton on Canal Navigation; Chapman's Observations on Canals, &c.; Leach on Inland Navigation; Anderson's Recreations; Smeaton's Reports on Civil Engineering; Nicholson's Philosophical Journal; Telford's Reports on the Caledonian Canal; Strickland's Reports on Canals, Railways, &c.; Cox's Travels in the North of Europe; Barrow's Travels in the North of Europe; Transactions of the Society of Civil Engineers; Transactions of Statistical Society; M'Culloch's Commercial Dictionary; M'Culloch's Statistics of the British Empire; Martin's History of the British Colonies; Journal of the Royal Geographical Society; Dupin's Commercial Power of Great Britain; Rennie on Hydraulics, in the Reports of the British Association; Fairburn on Canal and Steam Navigation; Macnill on the Resistance of Water, &c.; Priestley's Account of Canals, &c., in Britain; Hamilton's East India Gazetteer; Girard, Mémoires sur les Canaux, &c.; Huerne, Des Canaux Navigables; Dutens, Histoire de la Navigation Intérieure de la France; Dutens sur les Travaux Publics d'Angleterre; Warden's Account of the United States of America; Pitkin's Statistics of the United States; Flint's Geography of the Western States; the American Almanac; the Franklin Journal; Mechanics' Magazine; Railway Journal; Edinburgh Philosophical Journal; Edinburgh Review; Balbi, Abrégé de la Géographie; Tableau des Etats Danois, &c. (E.E.E.)