in Agriculture, the operation by which corn is separated from the straw. This operation is performed in a variety of ways, sometimes by the feet of animals, sometimes by a flail, and sometimes by a machine.

The most ancient method of separating the corn from the straw was by the hoofs of cattle or horses. This was practised by the Israelites, as we find from the books of Moses; it was also common among the Greeks and Romans*. Flails and thrashing machines were at * Pliny, so not uncommon among these nations†. The flail xviii. 35, which was used by the Romans, called baculatus, fastis, Verg. 6, or pertica, was probably nothing more than a cudgel or † Isaiah. The thrashing machine, which was called tribula ‡, Tibul, or tribulum, and sometimes trahia, was a kind of sledge‡, made of boards joined together, and loaded with stone or † Isaiah. Horses were yoked to this machine, and a man was Homer, seated upon it to drive them over the sheaves of corn. xx. 492.

Different methods are employed in different countries for separating the corn from the stalk. In the greatest part of France the flail is used; but in the southern districts it is generally performed by the feet of animals. Animals are also used for the same purpose in Spain, in Italy, in the Morea, in the Canaries, in China, and in the vicinity of Canton, where the flail is also sometimes used. It appears that in hot climates the grains do not adhere so firmly to the stalk as in cold countries, and therefore may be more easily separated. This will explain the reason why animals are so frequently employed in hot countries for treading out the corn; whereas in cold climates we know they are seldom tried, and have no reason to suppose that they would answer the purpose. In the Isle of France in Africa, rice and wheat are thrashed with poles, and maize with sticks; for it has not been possible to teach the negroes the use of the flail.

The animals used for treading out corn are, oxen, cows, horses, mules, and even asses when the quantity is not great. The operation is performed in this manner: The sheaves, after being opened, are spread in such a manner that the ears of the corn are laid as much uppermost as possible, and a man, standing in the centre, holds the halters of the cattle, which are made to trot round as in a manege; whilst other men with Threshing forks shake the straw up from time to time, and the cattle are trotted over it again and again till they have beaten out all the grain. This method is expeditious enough; but besides bruising a considerable quantity of corn, it requires a great many cattle, and injures the legs of the horses and mules, which are preferred before cows and oxen for this work.

The flail is undoubtedly a much better instrument for thrashing corn than the feet of animals, for it separates the grain from the straw and husks both more effectually and more expeditiously; yet it is liable to many objections. It is a very laborious employment, too severe indeed even for a strong man; and as it is usually the interest of the thrasher rather to thrash much than to thrash clean, a good deal of corn will generally be left upon the straw. It is therefore an object of great importance in husbandry to procure a proper machine for separating the corn from the straw.

The first threshing machine attempted in modern times, of which we have received any account, was invented in Edinburgh by Mr Michael Menzies about the year 1732. It consisted of a number of instruments like flails, fixed in a moveable beam, and inclined to it at an angle of ten degrees. On each side of the beam in which the flails were fixed, floors or benches were placed for spreading the sheaves on. The flails were moved backwards and forwards upon the benches by means of a crank fixed on the end of an axle, which made about 30 revolutions in a minute.

The second threshing machine was invented by Mr Michael Stirling, a farmer in the parish of Dunblane, Perthshire. Of this discovery we have received a very accurate and authentic account from his son, the reverend Mr Robert Stirling minister of Crieff.

It is an old proverb, that necessity is the mother of invention. This was verified on the present occasion. Besides his ordinary domestic servants, Mr M. Stirling had occasion sometimes to hire an additional number to thrash out his grain, and frequently found it difficult to procure so many as he needed. This naturally led him to reflect whether the operation of thrashing could not easily be performed by machinery. Accordingly, so early as the year 1753, under the pretence of joining in the amusements of his children, he formed in miniature a water mill, in which two iron springs made to rise and fall alternately, represented the motion of two flails, by which a few stalks of corn put under them might be speedily thrashed. This plan he executed on a scale sufficiently large within two years after, making the springs about ten feet long, each of which had one end firmly screwed into a solid plank, and the other terminated in a round baton of solid iron, two feet long and above an inch in diameter. Under these the sheaves were conveyed gradually forward in a narrow channel or trough, by passing between two indented horizontal cylinders, similar to those now used in the most of the thrashing mills in that part of the country, and called feeders. In this manner the thrashing was executed completely, and with considerable rapidity; but as the operation was performed on a low floor, and no method contrived for carrying off the straw, the accumulation of it produced such confusion, and the removal of it was attended with such danger that this scheme was very soon entirely abandoned. The mortification arising from disappointment, and especially the scoffs of his neighbours, for what was universally accounted an absurd and ridiculous attempt, served only to stimulate the exertions of the inventor to accomplish his designs on another plan.

Laying aside therefore the iron springs with the feeders, and all the apparatus adapted to them, he retained only an outer or water wheel, with an inner or cog-wheel moving on the same axle: to this inner wheel, which had 48 teeth or cogs, he applied a vertical trundle or pinion, with seven notches, the axle of which passed through a floor above the wheel, and having its upper pivot secured in a beam six feet above that floor. At the distance of three feet three inches above the floor two straight pieces of squared wood, each four feet long, passed through the axle of the trundle at right angles, forming four arms, to be moved round horizontally. To the extremities of these arms were fixed four iron plates, each 20 inches long, and eight broad at the end next the arms, but tapering towards a point at the other end. This large horizontal fly constituting four thrashers, was inclosed within a wooden cylindrical box three feet and a half high and eight in diameter. On the top of the box was an opening or port (two or three ports were made at first, but one was found sufficient) eight inches wide, and extending from the circumference a foot and a half towards its centre, through which the corn sheaves descended, being first opened and laid one by one on a board with two ledges gently declining towards the port; on which board they were moderately pressed down with a boy's hand, to prevent them from being too hastily drawn in by the repeated strokes of the thrashers. Within the box was an inclined plane, along which the straw and grain fell down into a wide wire riddle two feet square, placed immediately under a hole of nearly the same size. The riddle received a jerk at every revolution of the spindle from a knob placed on the side of it, and was instantly thrust backward by a small spring pressing it in the opposite direction. The short straw, with the grain and chaff which passed through the wide riddle, fell immediately into an oblong straight riddle, which hung with one end raised and the other depressed, and was moved by a contrivance equally simple as the other; and having no ledge at the lower end, the long chaff which could not pass through the riddle dropped from thence to the ground; while the grain and most of the chaff falling through the riddle into a pair of common barn-fanners that stood under it on the ground floor, the strong grain, the weak, and the chaff, were all separated with great exactness. The fanners were moved by a rope or band running circuitously in a shallow niche cut on the circumference of the cog-wheel. The straw collected gradually in the bottom of the box over the wide riddle, and through an opening two and a half feet wide, and as much in height, left in that side of the box nearest the brink of the upper floor, was drawn down to the ground with a rake by the person or persons employed to form it into sheaves or rolls.

Such was the threshing mill invented by Mr Michael Stirling, which, after various alterations and improvements he completed in the form now described, A.D. 1758. By experiment it was found that four bolls of oats, Linlithgow measure, could be thrashed by it in 25 minutes. From that period he never used a common flail in thrashing, except for humbling or bearding barley. In every other kind of grain he performed the whole operation of thrashing with the mill; and continued always to use it till 1772, when he retired from business, and his thrashing mill became the property of his second son, who continued to use it with equal advantage and satisfaction. Several machines were constructed on the same plan, particularly one near Stirling, under Mr Stirling's direction, for Mr Moir of Leckie, in 1765, which, we understand, has been used ever since, and gives complete satisfaction to the proprietor. There was another erected in 1778 by Mr Thomas Keir (in the parish of Muthill and county of Perth), who has contrived a method of beating barley with it; and by the addition of a small spindle with short arms contiguous to the front of the box, and moved by a band common to it and the great spindle to which it is parallel, the straw is shaken and whirled out of the box to the ground. That this machine did not come immediately into general use, was owing partly to the smallness of the farms in that part of the country, whose crops could easily be thrashed by the few hands necessarily retained on them for other purposes; and chiefly to an apprehension that the machine could only be moved by water; an apprehension which experience proves to be entirely groundless. The machine, however, was ingenious, and did great credit to the worthy inventor, and certainly deserved a better fate than it was destined to undergo.

A third thrashing mill was invented in 1772, by two persons nearly about the same time, and upon the same principles. The inventors were, Mr Alderton who lived near Alnwick, and Mr Smart at Wark in Northumberland. The operation was performed by rubbing. The sheaves were carried round between an indented drum of about six feet diameter, and a number of indented rollers arranged round the circumference of the drum, and attached to it by means of springs; so that while the drum revolved, the fluted rollers rubbed the corn off from the straw by rubbing against the flutings of the drum. But as a considerable quantity of the grain was bruised in passing between the rollers, the machine was soon laid aside.

In 1776 an attempt was made by Mr Andrew Meikle, an ingenious millwright in the parish of Tynningham, East Lothian, to construct a new machine upon the principles which had been adopted by Mr Menzies already mentioned. This consisted in making joints in the flails, which Mr Menzies had formed without any. But this machine, after much labour and expense, was soon laid aside, on account of the difficulty of keeping it in repair, and the small quantity of work performed, which did not exceed one boll or six Winchester bushels of barley per hour.

Some time after this, Mr Francis Kinloch, then junior of Gilmoreton, having visited the machine invented in Northumberland, attempted an improvement upon it. He inclosed the drum in a fluted cover; and instead of making the drum itself fluted, he fixed upon the outside of it four fluted pieces of wood, which by means of springs could be raised a little above the circumference of the drum, so as to press against the fluted covering, and thus rub off the ears of corn as the sheaves passed round between the drum and the fluted covering. But not finding this machine to answer his expectation (for it bruised the grain in the same manner as the Northumberland machine did), he sent it to Mr Meikle, that he might, if possible, rectify its errors.

Mr Meikle, who had long directed his thoughts to this subject, applied himself with much ardour and perseverance to the improvement and correction of this machine; and after spending a good deal of time upon it, found it was constructed upon principles so erroneous, that to improve it was impracticable.

At length, however, Mr Meikle's own genius invented a model, different in principle from the machines which had already been constructed. This model was made in the year 1785; and in the following year the first thrashing machine on the same principles was erected in the neighbourhood of Alloa, in the county of Stirling, by Mr George Meikle the son of the inventor. This machine answered completely the wishes of Mr Stein, the gentleman for whom it was erected, who gave the most ample testimony of his satisfaction both to the inventor and to the public. The fame of this discovery soon spread over the whole country, and a great many farmers immediately applied to Mr Meikle, desiring to have thrashing-mills erected on their farms. The discovery, it appeared, would be profitable, and it was reasonable that the inventor should enjoy the profits of his invention. He accordingly applied for a patent; which, after considerable expense, arising from the opposition of some persons, who claimed a share in the discovery, was granted.—These machines are now becoming very common in many parts of Scotland, and are increasing very considerably in number every year over all the united kingdom.

We will now endeavour to describe this machine in its most improved state; which is so simple, that with the assistance of a plate, exhibiting the plan of elevation, fig. 1, the ground plan, fig. 2, and the 3d showing its essential parts in a distinct manner, we hope it will be easily understood by all our readers who have not had an opportunity of seeing it. The power employed for turning that part of the machine which separates the corn from the straw is produced by four wheels (when moved by horses), the teeth of which move in one another and turn the drum, on which four scutchers are fixed. The sheaves are introduced between two fluted rollers, which hold them firm, and draw them in gradually, while the scutchers strike off the grain from the straw as it passes through. This will suffice for a general idea of this machine. We will now be more particular.

The large spur-wheel A, fig. 1. and 2. which has Fig. 1. and 276 cogs, is horizontal, and moves the pinion D, which has 14 teeth. The pinion B moves the crown-wheel C, which has 84 teeth; the wheel C moves a second pinion D, which has 16 teeth; and the pinion D moves the drum HIKL. The drum is a hollow cylinder three feet and a half diameter, and placed horizontally; on the outside of which the scutchers are fixed by strong screw bolts. The scutchers consist of four pieces of wood, faced on one side with a thin plate of iron, placed at an equal distance from each other, and at right angles to the axis of the drum.

The sheaves are spread on an inclined board F, fig. 3. Fig. 3. from which they are introduced between two fluted rollers GG made of cast iron, about three inches and a half in diameter, and making about 35 revolutions in a minute. As these rollers are only about three quarters Thrashing, of an inch distant from the scutchers or leaves of the drum HIKL, they serve to hold the sheaves fast, while the scutchers \(a, b, c, d\), moving with prodigious velocity, separate the grain completely from the straw, and at the same time throw out both grain and straw upon the concave rack M, lying horizontally with slender parallel ribs, so that the corn passes through them into a hopper N placed below. From the hopper it passes through a harp or riddle O into a pair of fanners P, from which, in the most improved machines, it comes out clean and fit for the market. The straw, after being thrown by the scutchers \(a, b, c, d\), into the rack, is removed from it by a rake QRST into a place contiguous V. The rake consists of four thin pieces of wood or leaves; on the end of each of these leaves is ranged a row of teeth \(e, f, g, h\), five inches long. The rake moves in a circular manner in the concave rack, while the teeth catch hold of the straw, and throw it out of the rack. These are all the essential parts of the machine; the rest may be easily understood by the references to the plate. W is the horse-course, No. 1, which is 27 feet diameter. X is the pillar for supporting the beams on which the axle of the spur-wheel is fixed. YYY are three spindles for moving the two fluted rollers, the rake, and fanners. To the description now given we have only to add, that the drum has a covering of wood Z at a small distance above it, for the purpose of keeping the sheaves close to the scutchers.

The advantages of this machine are many. As the drum makes 300 revolutions in a minute, the four scutchers together make 200 strokes in the same space of time. From such power and velocity, it is evident that much work must be performed. When the horses go at the rate of two and one-third miles per hour, from three to six bolls will be thrashed; but as the quantity thrashed will be less when the straw is long than when it is short, we shall take the average at four bolls. One gentleman, whose velocity and accuracy we can depend on, assures us, that his mill thrashed 63 bolls in a day; by which, we suppose, he meant 10 hours. To prove the superior advantage of this machine to the common method of thrashing with flails, a gentleman ordered two equal quantities of oats to be thrashed by the mill and by flails. When the corn was cleaned and measured, he obtained one-sixteenth more from the sheaves thrashed by the mill than from those thrashed by the flail. We are also informed by another gentleman who has studied this machine with much attention, and calculated its advantages with care, that, independently of having the corn much cleaner separated from the straw than is usually done by flails, there is a saving of 30 or 40 per cent. in the expense of thrashing.

The number of persons requisite for attending the mill when working is six: One person drives the horses; a second hands the sheaves to a third, who unties them, while a fourth spreads them on the inclined boards and presses them gently between the rollers; a fifth person is necessary to riddle the corn as it falls from the fans, and a sixth to remove the straw. (A)

This machine can be moved equally well by water, wind, or horses. Mr Meikle has made such improvements on the wind-mill as to render it much more manageable and convenient than formerly; and we are informed many windmills are now erecting in different parts of the country. As to the comparative expense of these different machines, the erection of the horse machine is least; but then the expense of employing horses must be taken into consideration. One of this kind may be erected for 70l. A water-mill will cost 10l. more on account of the expense of the water-wheel. A wind-mill will cost from 200l. to 300l. sterling.

THRAVE of CORN, an expression denoting 24 sheaves or four shocks of six sheaves to the shock; though in some countries they only reckon 12 sheaves to the thrave.