Thrashing, or Threshing, in rural economy, is the operation, by which grain is separated from the straw.

Thrashing is performed by different methods, in various parts of the globe: thus, in the eastern climates, corn is trodden out by oxen, cows, horses, mules, and even by asses: while in Europe, the flail is generally employed. This implement is certainly preferable to the feet of animals; as it is not only more expeditious, but the labour is executed in a much cleaner mode than can be effected by the latter. But, notwithstanding these advantages, thrashing with the flail, is liable to many objections ; being too laborious, even for persons of considerable strength: and, as they are often paid in proportion to the quantity of, corn thrashed, such work is seldom accomplished in a perfect manner; so that numerous grains generally remain in the straw. To remedy these in-conveniencies, machines of various construction, have been invented ; and, as some of these contrivances promise to be of great advantage to agriculturists, we shall give an account of the most valuable.

The first thrashing machine which has come to our knowledge, is that manufactured, in 1732, by Mr. Michael Menzies Of Edinburgh : it consisted, as far as we have been able to ascertain, of numerous instruments, resrmbling flails, which were attached to a moveable beam, and inclined to the latter in an angle of 10 degrees. On each side of such beam, were placed floors, or benches, on which the sheaves were spread ; the flails being moved forward and backward on these benches by a crank, that was fixed to the end of an axle, revolving about 30 times in a minute.

The second machine was invented, in 1753, by Mr. Michael Sterling, of Dunblaine, Perthshire : his first models were very imperfect; but, after repeated alterations, he completed it in its present form, in 1758 ; and it now consists of an outer, or water-wheel, having an inner wheel, furnished with 48 cogs, and turning on the same axle. With this cog-wheel is connected a vertical trundle, or pinion, with 7 notches; and the axle of which passes through a floor above the wheel; its upper pivot being secured in a beam 6 inches above the floor. At the height of 3 feet 3 inches from the latter, 2 straight pieces of squared wood (each being 4 feet in length) are inserted through the axle of the pinion, at right angles, so as to form 4 arms, that are moved round horizontally. To the ends of these arms are affixed 4 iron plates, each 20 inches in length, and 8 inches in breadth at the extremity nearest to the arms but tapering to a point at the opposite end.

The horizontal fly. here described, constitutes four thrashers, and is inclosed in a cylindrical wooden box, that is 3 1/2 feet high, and 8 feet in diameter: on the top of this box is an opening 8 inches in width, extending a foot and a half from the circumference to its centre, and through which the sheaves of corn descend; the latter being previously opened, and laid separately on a board provided with two ledges, gradually declining towards such port, or opening. - Within the cylindrical box, there is an inclined plane, along which the straw and grain fall into a wire riddle two feet square, that is placed immediately beneath a hole of a similar size : - the riddle is jerked at each revolution of the spindle, by means of a knob fixed on its side; and is thrust backward by a small spring that presses it in a contrary direction. Thus, the short straw, together with the grain and chaff, that pass through the wide riddle, fall instantly into an oblong, straight riddle, one end of which is raised, and the other depressed, by a similar contrivance. And, as the riddle last-mentioned is not provided with a ledge at the lower end, the long chaff, which cannot pass through, drops thence to the ground, while the grain and smaller chaff descend into a pair of common barn-fanners, and are thus separated with great exactness. These fanners are moved by means of a rope, that runs in a shallow groove cut on the circumference of the cog-wheel. In t!.e mean time, the straw collected in the lower part of the box over the wide riddle, and through an opening 2 1/2 feet square, is drawn down to the ground with a rake, by the persons employed to form it into trusses.

In 1772, another thrashing-machine was invented by Mr. Alderton, of Alnwick, and Mr. Smart, of Wark, Northumberland. The operation was performed by rubbing; the sheaves being carried round between an indented drum 6 feet in diameter, and numerous indented rollers, that were arranged round, and attached to, this drum by means of springs ; so that, during the revolution of the machinery, the corn was separated from the straw, by constant friction against the flu tings of the drum. But this contrivance was soon disused ; as many grains were thus crushed between the rollers.

Thrashing Machine

The next invention, is that of Mr. Andrew Meikle, in 1785, who obtained a patent, which is now expired : we have therefore given a plate, representing in Fig. 1, the plan of elevation; in Fig. 2, the ground plan; and in Fig. 3, the Essential parts of the machinery, so as to convey a tolerably accurate idea of his principle.

Description of Mr. Andrew Mei-kle's Improved Thrashing Machine.

A, (Fig. 1, and 2), is a large horizontal spur-wheel, which has 276 cogs, and moves the pinion B, having 14 teeth. The latter imparts motion to a crown-wheel, C, that is provided with 84 cogs, and moves a second pinion, D, which is furnished with 16 teeth. This pinion, D, turns the drum H, I, K, L, (Fig. 1, 2, and 3), being a hollow cylinder, 3 1/2 feet in diameter, and placed horizontally : on its outside are fixed, by means of screw-bolts, four scutchers, or pieces of wood, one side of which is faced with a thin iron plate ; and which are disposed at an equal distance from each other, and at right angles to the axis of the drum.

F, (Fig. 2, and 3), is an inclined board, on which the sheaves are spread, and whence they are introduced between two fluted cast-iron rollers, G, G, (Fig. 3), that are 3 1/2| inches in diameter, and revolve about 35 times in one minute. These rollers, being only three-fourths of an inch from the scutchers or leaves of the drum H, I, K, L, (Fig. 1, and 2), serve to keep the sheaves steady, while the scutchers a, b, c, d, (Fig. 2, and 3), move with uncommon velocity, and thus separate the grain from the straw, while both are thrown on the concave rack M, (Fig. 2), which lies horizontally with slender parallel ribs ; so that the corn may pass through them, into the subjacent hopper N, (Fig. 1, and 3).

O, (Fig. 3), is a riddle or harp, through which the corn drops into a pair of fanners, P, (Fig. 1, and 3), and from these it is generally obtained in a state fit for the market.

Q, R, T, S, is a rake, consisting of four leaves, or thin pieces of wood : at the extremity of each is placed a row of teeth e, f} g, h, that are five inches long. This rake moves in the concave rack M, (Fig. 2), in a circular direction ; while the teeth catch the straw, that had been thrown by the scutchers a, b, c, d, into the rack, and remove it to the contiguous place, V.

W, (Fig. 1), represents the horse's course, which is 27 feet in diameter.

X, (, Fig.1, and 2), is the pillar for supporting the beams, on which the axle of the spur-wheel is fixed.

Y, Y, Y, (Fig. 1), and Y, Y, (Fig. 2), shew the spindles, the design of which is to move the two fluted rollers; the rake, and the fanners.

P. Z, (Fig.

Z, (Fig. 1), is a wooden cover-ing at a small distance above the drum, for the purpose of keeping the sheaves close to the scutchers.

Mr. Meikle's thrashing-ma-chine may be worked with equal effect by horses, by water, or by the wind. If the first of these mechanical powers be employed, the whole, we understand, costs about 701.; in the second case, it amounts to about 80l., on account of the additional expence of the water-wheel; and, if the thrashing-machine is to be turned by the wind, it cannot be erected for a less sum than from 2001. to 3001. sterling. Although such disbursement be, at first, very considerable, yet numerous machines on this principle have lately been erected in Scotland ; because they are eventually cheap, by saving the labour of men, and the keeping of horses.

Six persons are required to attend the thrashing-mill; and, though a similar number be employed with the flail, and for clearing an equal quantity of corn from chaff, yet by the former method, the work is more cleanly, and expeditiously, performed.

The advantages that may be derived from Mr. Meikle's ingenious contrivance, are too obvious to require an enumeration: we shall therefore only observe, that the drum makes 300 revolutions in one minute, and the four scutchers give 1200 strokes in the same space of time : consequently, much work must be executed from such velocity ; and, if the horses walk at the rate of 1\ miles every hour, from 3 to 6 bolls (or from 12 to 24 English bushels) will be thrashed every hour. Thus, the grain is not only separated in a more per-fect manner than is practicable by the flail, but a saving of 30 or 40 per cent, is also obtained in the ex-pence of thrashing.

Another machine was invented, a few years since, by Mr. James WaRdrop, of Ampthill, Virginia; for the purpose of separating corn from straw ; and of which we have procured the following Cut;

Thrashing Machine, with Elastic Flails

Description of Mr. James Ward-Rop's Thrashing Machine, with Elastic Flails.

A, the floor, over which the flails are fixed.

B, represents that part of the floor, on which the sheaves are laid : it is made of wicker-work, through which the grain falls, and is conveyed to the fan or screen below; the pivot of the fan is delineated at P, and is turned by a band from the wheel or wallower, D.

C, C, C, is a thin board raised round the floor, to prevent the wheat from being scattered; and which is made shelving outwards, that the straw may be raked off mote easily.

D, the wheel or wallower.

E, crank-handle for turning the wheel.

F, F, F, are the flails.

G, G, G, levers or arms, to which flails are attached by mean's of ropes.

H, H, H, are teeth or catches for raising the arms.

I, the post, on which the wallower D, is fixed.

K, K, the beam on which the levers rest; being fixed by an iron rod passing through them, and inserted into this beam.

L, L, a check-beam, to prevent the end of the arms from rising.

M, a beam, into which the ends of the flails are mortised.

N, N, N, are fly-ends, weighted with lead, but which are not necessary in a machine that is set in motion by horses.

To render the operation of the machinery somewhat more evident, we have annexed another, though only partial, view of it, together with a few additional explanations-.

Thrashing Machine 3

This figure represents the arms G, G, G, working in the keeps, O, O, O, and also the manner in which those parts are connected.

The model from which these delineations have been made, was designed to be worked by two men : it was constructed on the scale of a twelve-foot flail, having a spring that required a power of 20lbs. to raise it three feet high at the point. The teeth or catches: are mortised into the shaft of the wallower, and placed round its circumference; so as to form an angle of 30 degrees. These teeth catch the arms G, G, G, that raise the flails, alternately : thus, the whole power, namely, 20lbs., acts upon three of the flails, when they are about to strike ; three others are two-thirds raised ; three more are elevated one-third; and the remaining three flails are at rest; so that the whole weight to be overcome, amounts to 120lbs.

Mr. Wardrop directs the arms to be arranged in such manner, that a fine drawn perpendicularly from their lifting extremity, would extend to the middle of the flail: the ropes must be fixed somewhat nearer towards the end, that a proper tangent may be obtained. Farther, the extremities of the lifters, and the teeth in the wallower, should be rounded off, so as to form a tangent with each other. The ropes ought also to be fixed to the flails with a hook and eye, in order to be removed, when not at work ; for, some of the flails being continually in a lifting state, their elasticity would otherwise be impaired. Lastly, such flails acquire greater power, in proportion to the extent of their length, and the height to which they are raised: they operate with effect at one-third of their length ; and consequently a flail, that is 24 feet long, will act with force about 8 feel on the floor ; a size which is recommended by the inventor, for thrashing-machines worked by horses.

In Mr. Boys's General View ef the Agriculture of the County of Kent (8vo. 4s. Nicol), we meet with an account of a thrashing-machine erected in a barn on his farm : - as our limits will not permit us to describe its mechanism, •we shall only remark, that it requires four horses, eight men, and four boys, to remove the corn from a distant part of the barn ; to feed the mill ; attend the winnowingfan ; and stack the straw. Thus, if the corn yield abundantly, the machine will thrash out three quarters of wheat, four of barley, or Jive of oats, WitKin one hour, in a cleaner manner than can be effect-ed by the usual mode; so that nearly one-half of the expence will be saved.

The latest thrashing-machine, which has come to our knowledge, is that invented by Mr. John PalmeR, of Maxstock, Warwickshire; for which he obtained a patent in 1799. Not having been able to procure a specification of his privilege, we can only state that the machine may be worked, either by one or by two horses, as cir-cumstances may direct; but a larger number will, according to the patentee's assertion, never be required : it may also be set in motion by any other equivalent power. By this contrivance, 24 sheaves of wheat or other grain, each being one yard in circumference, may be thrashed out in five minutes ; the straw and grain are completely separated, and the former will be less injured than if the operation were performed with a flail. Farther, no additional building is required for the management of the machine, which may be erected in any barn of an ordinary size, and can be removed to different barns, at a very trifling expenee.

Many objections have been started against the introduction of thrashing machines into rural economy ; and it has been particularly urged, that the labour and earnings of the poor must necessarily decrease, and a great redundance of straw will be occasionally produced. Such inconveniences, however, may be easily obviated : for, exclusively of the grain thus secured and saved from the depredations of dishonest workmen, the latter will never be without employment in a country-, where extensive tracts of ground lie uncultivated, and the population of which, together with the numerous persons devoted to manufactures and navigation, as well-as the importation of com, by which the national treasury is gradually exhausted - all these circumstances impose the absolute necessity of cultivating every acre of waste land. Farther, by adopting such machines, the grain is not only more speedily separated, but it may also, in damp seasons, be thrashed out clean; an object which could not be fee accomplished by the flail: and, if any smut-balls occur in the ears, they will not be broken, but a considerable portion of them be dispersed in winnowing. Lastly, a larger quantity of chaff is thus obtained ; and, though too great a stock of straw may be produced, for immediate consumption, yet if such article be closely and carefully stacked, it will not be easily injured by keeping.