Threshing Machine, a machine for threshing and separating grain from the straw. The threshing floor of the ancients was a flat surface of ground covered with clay rolled smooth and hard. Sheaves of grain were spread evenly on this floor, and cattle driven over it until the grain was beaten out by the constant tramping upon it. The Egyptians usually muzzled the ox while threshing, and the Greeks are said by AElian to have had the filthy practice of besmearing the mouths of animals with dung to prevent their eating the grain. The flail, which is yet in common use by small farmers, is a very ancient invention. . Planks or timbers stuck over with pieces of flint or hard wooden pegs were used to some extent, but answered no good purpose. Michael Menzies of Scotland is supposed to have been the first inventor of a machine for threshing, which was merely an adaptation of suitable mechanism to drive a large number of flails by water power. Though unsuccessful in practice, this machine attracted considerable attention. In 1758 a Stirlingshire farmer named Leckie invented a rotary machine which consisted of a set of cross arms attached to a horizontal shaft, and the whole enclosed in a cylindrical case.

It proved tolerably efficient in threshing oats, but was not adapted to wheat, as it knocked off the entire head from the straw without separating the kernels. Mr. Leckie having demonstrated the superiority of a rotary motion for this purpose, it was an easy matter to remedy the defects of his machine and perfect the invention. In 1786 Andrew Meikle, a Scotchman, made an improvement on Leckie's machine by substituting a drum or cylinder with beaters attached to the circumference. He also applied rollers, connected by suitable mechanism to the driving gear, for feeding in the straw. When operated, the drum was set in rapid motion by water or other power; the sheaves of grain, unbound and placed between the rollers, were fed in; and the beaters, revolving with great velocity on the periphery of the drum, beat out the grain from the heads and partially separated it from the straw. A patent was procured in Great Britain in 1788, when Mr. Meikle constructed the first working machine, and added many new improvements, among which was the attachment of a fan mill, by which the grain was separated and cleaned from both straw and chaff.

Though an invention of vast importance, saving annually millions of dollars' in manual labor, and immenselv increasing the product of grain throughout the civilized world, the simplicity of the threshing machine and the perfection of Meikle's inventions left little room for great modern improvements. Meikle's, with some modifications, was the first form of drum machine used in the United States; but although the beater drum is still used in Great Britain, it has long been replaced here by the spiked drum, which runs at a higher speed. This form of machine consists principally of a concave bed made of heavy plank lined with iron spikes arranged spirally, into which the drum, also armed with spirally disposed spikes, revolves. Such machines are capable of threshing 300 bushels of oats and over 100 of wheat in 10 hours. Most modern threshing machines have grain separaters attached, by which the grain is winnowed by a revolving fan, and also elevators which are long endless aprons moved on rollers, by means of which the straw is taken up into a mow or on to a stack. Numerous machines of this kind are employed in the United States, especially in the Mississippi and Ohio region.

In many places where the farms are not large, it is the practice to employ threshers who move their machines, which are on wheels like those of a wagon, from place to place.

Geiser's Threshing Machine.

Geiser's Threshing Machine.

One of these machines, patented by Peter Geiser, is represented in the engraving. M is the feeding board, and I the toothed drum, which throws the straw and threshed grain on to an inclined plane between I and B. Between B and C there is a rack, through which the grain falls, while the straw is moved forward on to the elevator N by means of a reciprocating rake. The grain falls back on an inclined plane to E, thence down over the fluted rollers E and F, where, receiving the air blast from the revolving fan II, the chaff is blown away, the grain passing down into receptacles below. Lighter grains and seeds of weeds are blown further, beyond a screen, and are carried along with some good grain by an elevator, back to the thresher at L, by which means all the good grain is saved.