Engineering Wonders of the World
Volume III

AGRICULTURAL ENGINEERING. 295 to which they were accustomed, they sus- pected it of being unreliable. But in due course the machine attained a state of perfection which established its value beyond dispute. The self-bind- ing apparatus, which passes twine round the sheaf, knots it, and cuts it off, was added, so doing away with the labour of the three or four men who The Self= binder. open end of the machine. Pieces of straw and any stray grains, seeds, or husks that escape the drums fall through the shakers on to sieves, and by them are fed to the blowers, which blow away the short straws. The grain, husks, and dust are then subjected to further winnowings, and finally the grain and seeds only remain to be dealt with. A series of sieves effects the separation, allowing the seeds COMBINED HARVESTER AND THRESHER AT WORK IN THE BIG BEND COUNTRY, WASHINGTON. The sacks seen in the foreground have been filled with grain and dropped by the machine. formerly had followed a reaper to tie up the grain which it discharged. From that time onward the importance of the reaping-machine has increased. Vast numbers of machines are manufactured annually for use in all parts of the world. What the self-binder is to the reaping-hook, the modern threshing-machine is to the old- fashioned flail. The corn, fed in through an opening in the top, is caught The Thresh- i a drum anc[ rubbed ing-machine. / between it and a breastwork, which knocks out most of the grain, and flings the straw forward on to a series of shakers. These move the straw slowly towards the and very small grains to pass, but retaining the good grain. The last reaches an elevator, which, by means of an endless band of cups, whisks it up to a hopper. From the hopper it falls on to another series of screens for a final winnowing, and thence passes ifito an inclined rotating cylindrical screen. This screen is divided into two sections. The first section has its wires set close together. The smallest grain, the “ thirds,” escape through it into a hopper and so to a sack. The “ seconds ” are freed by a second section, and the “ firsts ” drop out of the end of the screen. From start to finish the processes are purely auto- matic.