370 



SCIENCE OF AGRICULTURE. 



Part II. 



2457. The rope-twisting -machine ^Jig. 271.), is a small wheel, 27. 

 the prolonged axle or spindle of which terminates in a hook, on 

 which the rope is commenced. , It is commonly fixed to a port- 

 able stand ; but is sometimes attached to a threshing-machine. 

 It is used for twisting ropes of straw, hay, or rushes for tying 



..on the thatch of ricks and other similar purposes. It is also 

 used to form very thick ropes for forming straw drains. 



2458. The draught-machine is a contrivance invented for the 

 purpose of ascertaining the force or power of draught, in 

 drawing ploughs, &c. 



2459. Move's draught-machine is a spring coiled within a" 

 cylindrical case, having a dial-plate marked with numbers like 

 that of a clock, and so contrived that a hand moves with the motion of the spring, 

 and points to the numbers in proportion as the force is exerted : for instance, when 

 the draught equals one cwt. over a pulley, the hand points to fig. 1 ; when the draught 

 is equal to two cwt. it points to fig. 2, and so on. Till this very useful machine was 

 invented, it was exceedingly difficult to compare the draught of different ploughs, 

 as there was no rule to judge by, but the exertions of the horses as apparent to the 

 eye ; a very undecisive mode of ascertaining their force. 



2460. Brahys draught-machine (Jig. 272.), consists of two strong steel plates, joined 

 at the ends, and forming a spheroidal opening between them. In using it, one end (a) is 

 hooked on the muzzle of the plough or other implement, and to the other (i) the draught 

 trees are attached. An indicator (c) points out the power applied in cwts. 



2461.. The weighing-cage [Jig. 273.), is a contrivance made in the form of a sort 



273 



of open box or cage, by which any small animal, as a pig, sheep, calf, &c. may be very 

 easily and expeditiously weighed, and with sufficient accuracy for the farmer's purpose. 

 It is constructed on the principle of the common steel-yard, with a strong wooden frame 

 and steel centres, in which the pivots of the lever are hung. And upon the short side 

 of the lever is suspended a coop, surrounded by strong net- work, in which the animal 

 intended to be weighed is placed ; the point of suspension is connected with the coop by 

 means of two curved iron rods, which at the same time form the head of it. A common 

 scale being hung on the longer side of the lever. 



2462. The weighing-machine is a contrivance of the steel-yard kind, for the purpose 

 of weighing cattle and other animals alive. A machine of this sort is of importance in 

 the grazing and fattening systems where they are carried to any considerable extent, in 

 ascertaining the progress made by the animals, and shewing how they pay for the use of 

 any pai'ticular kind of food, or what power it has in promoting the fattening process. 



2463. Weir's machine for weighing live bullocks, is by far the simplest and most econo- 

 mical of these machines. 



2464. The weighing-machine for sacks is a convenient piece of barn-furniture on the 

 steel- yard principle. 



2465. The common steel-yard will often be found useful for weighing corn or roots in 

 large quantities ; for smaller quantities, there are a variety of ingenious contrivances, 

 among the simplest and easiest managed of which are those of Medhurst and Marriot. 



2466. The chaff-cutter is used for cutting hay or straw into fragments not larger than 

 chaff to facilitate its consumption by cattle. There are numerous forms; one of the most 

 common is that of M'Dougal {fig. 274.), which is so formed, that in case of its being 

 accidentally broken, it may be repaired by any common mechanic. The pressure of the 

 straw is also capable of being regulated with great facility. But the great im- 



