62 ON THE THRASHING-MACHINE. 



fact, the quantity ordinarily thrashed by a two-horse power 

 machine does not exceed three quarters per liour. A ma- 

 chine requiring" a motive force of three horses, commonly 

 thrashes from live to eight quarters ; and a four-horse power 

 is expected to thrash, on an averag'e, about ten quarters per 

 hour; but it may frequently accomplish twelve, and even 

 fourteen quarters. It may not be amiss to insert in this 

 place, the dimensions of the principal parts of a thrashing- 

 machine of the latter power, which was recently erected for 

 a gentleman in this county, and is allowed to be of the most 

 approved construction. The impelling- ag-ent is water ; the 

 diameter of the wheel is 11 feet; and the buckets are 3 feet 

 4 inches in width. The feeding' rollers are 3^ feet in length; 

 the diameter of the drum is 3 feet 2 inches ; and that of 

 the shaker is 5| feet. A winnowing- apparatus, driven by 

 Barker's centrifug-al wheel, is attached to the thrashing-- 

 machine. Being; furnished with two "hoppei-s," it can be 

 emploj'ed in dressing" g-rain either simultaneously with the 

 thrashing', or when the machine is not in operation. The 

 cost of erecting- the whole machinery was 58/. The average 

 rate of thrashing is twelve quarters per hour ; and the quan- 

 tity of water necessary to accomplish this work varies from 

 IGOO to 2000 cubic feet for every quarter, according to the 

 quality of the corn and the length of the straw. 



The thrashing-machines employed in this county vary 

 very much in size and power, ^ in consecjuence of the great 

 diversity that exists in the size of farms. A four-horse- 

 power machine is commonly used on farms ranging from 

 150 to 300 acres, a three-horse-power on those varying from 

 80 to 150 acres, and a two-horse-power on the smaller class 

 of farms from 25 to 80 acres. A machine requiring- only 

 the ])ower of one horse to propel it, is sometimes resorted to 

 on small possessions of about 20 acres. The grain-crop on 

 lioldings under the last - mentioned size is most generally 

 thrashed by the flail; and the cottagers perform this o])era- 

 tion in the winter mornings by the light of the lamp, or 

 diu-ing inclement weather, when out-of-door labour is sus- 

 pended. It is supposed that the thrashing-machines at 

 present employed in Aberdeenshire are impelled by an 



' A simple rule for ascertaining the power of a water-impelled tlirasliing- 

 raachine is to cube the radius of the wheel, multiply the square-root of this 

 by the area of the transverse section of the water where it impinges on the 

 wheel, and divide the product by 0^ : the quotient is the horse-power to 

 which the wheel is equivalent. 



