Page:An Encyclopædia of Cottage, Farm, and Villa Architecture and Furniture.djvu/691

 INTERIOR FINISHING OF FARMERIES. 66? from the straw, one floor on the ground is sufficient ; but when, in addition to separating the corn from the straw, the corn is to be winnowed and sifted by the macliine, a loft or second floor, from eight to ten or twelve feet, over the first, is essentially necessary. This floor is used for containing the unthreshed corn, which is commonly carried into it from the rick-yard, on hand-barrows, up an inclined plane or gangway ; but which is some- times albo carted into it, up a broad inclined plane, the cart being unloaded and turned round in the loft. Tliis mode of carting the corn into the loft is only to be met with on very large farmeries, or where the buildings are particularly situated ; such as being on a declivity : a more common practice is, to set back a cart loaded w ith sheaves within the barn on the ground floor, and unload it, forking up the sheaves to the threshing- floor, as in Mr. Donaldson's very excellent Design, § 891. From this floor there is a communication by a stair, or step-ladder, with the floor below on which the corn is cleaned, and from this cleamng-room there is a communication with the chaft-room adjoining, in which the chaif and refuse are contained. A clear idea of the arrangement of threshing-machinery, impelled by horses or water, relatively to the walls and floors of the barn, may be obtained by referring to our Encyc. of Agr., 2d edit. § 2786 to 2790, and the ibllowing Design will give an idea of the arrangement where steam is em- ployed. 1396. The Fitting-up of a Steam Tlireshing-machine. The application of steam to agricultural purposes has hitherto been very partial, and almost entirely limited to im- pelling the threshing-machine. Till lately, low-pressure engines only were used for this purpose ; but Mr. Burstall, an ingenious engineer at Leith, has now introduced, very extensively, the high-pressure or non-condensing engines. " These seem to be superior to the low-pressure engines in various respects : first, such engines are considerably cheaper in the original cost ; secondly, they do not require more than one twelfth or one twentieth part of the water which is requisite for a condensing engine ; and, thirdly, a knowledge of their management is more easily acquired. They are thus rendered more fit for farm labour ; and, when properly made, are certainly as safe as, if not more so than, condensing engines." 1397. The ^-Ipplication of Mr. Burstall's method of employing a high-pressure engine for moving a thresliing-machine is extremely simple. It is well known that there are two modes by which, in mechanics, a slow motion with great power may communicate a rapid motion. The first is, by means of wheels and pinions ; the second, by means of smootli or iron cylinders, to which a broad strap adheres by its friction, and conveys the power from the prime mover to the acting agent. In the one case, there is a constant and definite number of teeth acting on each other ; in the other case, there is what may be considered as an infinite number of teeth : that is, the surfaces of the belt and cylinder, applied to each other, produce the same result. The use of the belt to drive machinery is of much later date than that of toothed wheels ; but it may be safely affirmed, that, where high velocities are required, the former method has considerable advantages, and is gaining ground in the practice of machinery. Mr. Burstall is, we believe, the first who has made a successful attempt to drive the main cylinder or drum of a threshing-machine by the direct application of this principle ; and among other great advantages of the belt over gearing is this, that, should foreign substances get into the mill, the belt is at once thrown off, and this is all the injury that results; whereas, when with wheels and pinions a like accident occurs, an expensive wheel or shaft is generally broken. For these reasons, Mr. Burstall communicates directly the motion to the machinery of a threshing-mill by means of a belt. The method will be seen from the accompanying figs. 1285 and 1287. The application of the steam power, in this case, is made to an old threshing-mill, formerly driven by horse power and gearing, and altered to steam and belts. The machinery for driving the rakes and rollers has been retained, although it is clear that, as the main machine is well driven by a strap, the subordinate parts, which do not take one sixth of the power, can be so driven likewise. 1398. Details. Fig. 1285 is a ground-plan of a thresliing-mill, with the barn walls and steam-engines. Fig. 1286 is the end elevation of the steam-engine as placed out- side of the bam walls in the engine-house. Fig. 1287 is a front elevation of the steam-engine. The letters of reference are the same in the three figures ; a a are the rakes ; b, the drum and scutchers ; c, the feeding or supplying roller ; d, the feeding- table ; e, a rigger, or smooth cylinder, fixed upon the end of a shaft that couples to the drum-shaft of the threshing- mill ; y is the belt, from eight to ten inches wide, accord- ing to the power of the mill ; g, the fly-wheels of the steam-engine, lined up with wood, to form a drum for the belt to run upon ; h, the shafts and gearing to drive the rakes and rollers ; i, the barn wall ; /:, the wheel and pinion from the main shaft. It is under- stood that the machines erected by Mr. Burstall on this simple principle have given great satisfaction. (Highland Sac Trails., vol. xi. p. 235.) 1399. Of Threshing-machines driven by Water, the most complete which we know of