438 



SCIENCE OF AGRICULTURE. 



Part II. 



formity of- the movement. This will be acknowledged by any judge of the subject who witnesses the 

 performance. The sudden jerks and strains that generally take place in the usual way, are found to be 

 quite removed ; the machinery moving with the same kind of uniformity as if driven by water. In conse- 

 quence of which the work is better performed, and that in a very perceptible degree. 



water threshing-machine (Jt^^ 

 |\ 



2788. Meikle's water threshins-machine ( Hu.. 401.) is the preferable engine, when a 



supply of water can be 

 obtained. The main axle 

 or shaft (a), upon which is 



\/\ I fixed the water-wheel (6), 



has placed upon its cir- 

 cumferoncecast-metal seg- 

 ments {c), the teeth of 

 which turn the pinion 

 which is fastened on the 

 axle of the threshing- 

 drum ; the platform, on 

 which the unthreshed corn 

 is spread, joins the fee(C 

 ing rollers, that conduct 

 the corn forward to the 

 /v/v^ . ~ threshers ; next the thresh- 



ing-drum is the straw-shaker, driven by a leathern belt, passing over a sheeve, fixed on 

 an iron spindle connected with the axle of the water-wheel and the sheeve on the axle 

 of the shaker. 



2789. Meikle's threshing viachine to be driven by water or by four horses {Jig. 402.), is 

 a powerful and convenient engine, as advantage may be taken of water when it is 



LJ^-^^- 



abundant, and in dry seasons horses can be applied. To this machine the improvea 

 apparatus for yoking the horses is appended, and by the simple operation of varying the 

 positions of the pinions on the common shaft (a), which communicates with the water and 

 horse- wheel {b, c), threshing may be carried on without interruption, either with the water 

 or the horses separately ; or a small quantity of water may be applied to assist the horses 

 at any time, when a sufficient supply of water cannot be obtained to impel the machine 

 alone. 



2790. Meikle's threshing ma chitie to be driven either by tdnd or six horses (Gray, 

 PI. XII.) is a powerful but costly erection. On large corn farms, however, it will 

 answer to erect such machines ; and there are frequent instances in Berwickshire and 

 Northumberland, of farmers incurring that expense on the security of twenty-one years' 

 leases. The machinery of the wind power of this machine is fitted up with a small 

 van to turn the large ones to face the wind, and with the machinery necessary to 

 roll on or off the sails according to its increase or diminution ; by which means the 

 naturally unsteady power of wind is rendered as regular as that of horses or water. 

 The threshing part of this machine contains the usual apparatus, and also a complete 

 set of fanners and screens for cleaning the com. To the board upon which the 

 unthreshed grain is spread, and introduced between the feeding rollers, succeeds the 

 drum, with the threshers, or beaters, fixed upon the extremity of its arms; then the 

 shaker, that receives the straw from the threshing drum, and conveys it to the second 

 shaker, by which it is thrown down a sloping searce, either on the low floor, or upon a 

 sparred rack, which moves on rollers, turned by the machine, and by this means is con- 

 veyed into the straw-shed, or else into the barn yard. One searce is placed below the 

 threshing-drum ; and, while the drum's circular motion throws out the straw into the 

 straw-shaker which conveys it to the second shaker, the chaff and grain pass at the same 



