The flinnrys are moved by a crossed rote, passing over a pulley 'I', 10 inches diameter, fixed on the axis of the cylinder, and another V of S inches diameter, on the axis of the fanners. Then, as the axis of the cy linder makes 216.56 revolutions per minute, we have 216.56 X = 210.7 revolutions of the farmers per mi nute.
From the above it appears, that when The water wheel makes 51 revolutions in one mi nute, The cylinder will make 216,1 ditto, The rollers nearly, The rake 14 ditto, and clears the skrecn of straw 56 times per minute, The fanners 2701 ditto, The switchers make 866 strokes per minute, and move with a velo city of 2720 feet per mi nute.
The rollers take in nearly 300 inches of corn per minute. The medium length of good oats is about 30 inches ; and, supposing half a sheaf put in at a time, a whole sheaf will then be equal to 60 inches ; There r.i09 = 5 sheaves per minute, which agrees with the usual rate of going of this machine, when supplied with a medium quantity of water. From some expe riments lately made, 120 sheaves of oats were thrashed in 22 minutes, and yielded 12 bushels, which is at the rate of 33 bushels per hour, or 264 per clay of eight hours.
The i.unciisr. for the attendance of the thrashing and dressing part of this machine, is only that of three wo men ; viz. one to feed-in, another to hand the sheaves lo the feeder, and the third to take away and riddle the alter it is n 111110 \VCd : of course, the expense of •ltrashim.: and dressing bushels is only Is. 6d.
The expense of thrashing the same quantity by the ( ow• :• cnIv-lift.h part, or 10.,!. bushels, NvIlich, at 2s. per bushel, is 21 to which mutt be adc ed 28., the expense of a man and two women to assi,.. in IA innowing, making in all 23s.
The expense of erecting a thrashing machine of kind was hunt• 701. to 801.; but since the advance of wood, iron, and wages, it will he now near RM.
Machines of small dimensions arc erected for about 50l., which, with two horses, will thrash and dress 120 bushels of oats, or 60 of wheat, in eight hours.
Rollers, or small millstones, are added to many of these machines, for crushing or grinding grain for horses, swine, &c. Knives fur cutting straw, and many other useful appendages, might be added.
Small machines arc used for thrashing in many places; but we have doubt respecting the advantages of such implements. Allowing, that the work is equally well
performed with a small machine as with a large one, still it is unquestionably true, that the expense of thrashing must be greater when the farmer is employ ed; because the time of one person must be occupied in feeding the machine, whether one boll or ten bolls of grain be thrashed within the hour. This is an objec tion to small machines, which cannot be gotten over, even were it allowed that the grain is equally wel! thrashed ; a circumstance concerning which we have considerable doubts. It is one of the defects, however, which attend small farms ; for it is almost impossible upon them to make a suitable division of labour in any case. The best machine is that which is impelled by a six-horse power ; because such a machine is well qualified to thrash every kind of grain perfectly, while, at the same time, full employment is given to the feeder. On small farms, we have always considered the flail to be the most profitable implement for thrashing grain ; because the expenditure incurred in erecting a suitable machine, would exceed the probable benefit. Perhaps thrashing machines can rarely be worked with advantage upon a farm where less than one hundred acres are an nually cultivated ; and, it is evident, without demonstra tion, that the benefit of using them is in direct propor tion to the quantity of corn that is cultivated. If we shall suppose, that the interest upon outlay, and the tear and wear of a thrashing machine, is fifteen pounds to annum ; and that 800 bolls of grain are raised, when 100 acres are cultivated, the charge, on these accounts, is precisely fourpence halfpenny per boll. If the farm is of such a size as to admit the raising of sixteen hun dred bolls, the charge is reduced to twopence farthing per boll ; but should the return amount to two thousand four hundred bolls, the charge will be no more than three halfpence per boll. This is a true view of the business, when interest on outlay and tear and wear are to be considered ; and proves, what has seldom been questioned, by those who have studied the science of ru ral economy, that a large farm may be managed com paratively at much less expense than a small one.