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 also not uncommon among these nations†. The flail which was used by the Romans, called baculus, fustis, or pertica, was probably nothing more than a cudgel or pole. The thrashing machine, which was called tribula or tribulum, and sometimes troba, was a kind of sledge made of boards joined together, and loaded with stone or iron. Horses were yoked to this machine, and a man was seated upon it to drive them over the sheaves of corn.
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 raised 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 frequently 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 threshed 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 halter of the cattle, which are made to trot round as in a manege; whilst other men with 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
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*Pliny, xviii. 30. †Virgil, Georg. iii. 132. Col. ii. 21. Tibull. i. 5. 21. *Hesiod, xviii. 27. Homer, II. Ex. 493.
Vol. XVIII. Part II. Thrashing 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 and an half feet 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 an 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 palled through the wide riddle, fell immediately into an oblong flail 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 an 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 thrashing 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 hulling 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 continues 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 bearding 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 Allswick, 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 Tyningham, 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 five Winchester bushels of barley per hour.
Some time after this, Mr Francis Kinloch, then junior of Gilmerton, 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 The advantages of this machine are many. As the drum makes 300 revolutions in a minute, the four flutes together make 1200 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 veracity and accuracy we can depend on, affirms 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 1/8th 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 fanners, 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 windmill 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 L.70. A water mill will cost L.10 more on account of the expense of the waterwheel. A windmill will cost from L.200 to L.300 Sterling.
THRAVE OF CORN, an expression denoting 24 sheaves, or four shocks of six sheaves to the flock; though in some countries they only reckon 12 sheaves to the thrave.