430 



SCIENCE OF AGRICULTURE. 



Part 1 1. 



building on a greater load of hay, straw, or corn in the sheaf. This frame is held on by 

 no fastening, but remains in its place from being fitted to the exact width of the body of 



384 



the cart. On drawing out an iron pin, the fore part of the body rises up from the shafts, 

 while the other end sinks, and allows the load, whether of dung, earth, or stones in the 

 close cart, or of hay, or sheaves of corn, on the cart and frame, to fall to the ground. 

 2753. The Scotch corn cart {Jig. 385.) consists of open framework, with a boarded 



bottom, and is used solely for the 

 purpose of carting hay, corn in the 

 sheaf, or similar materials. It is 

 light, cheap in construction, and 

 contains a bulky load, which, being 

 lower and more extended than a 

 load on a coup cart with a frame, 

 is less likely to be overturned. 



2754. The Scotch two-horse cart 

 differs little from the one-horse 

 cart, except in being larger. To 

 prove the inferiority of double to single horse carts, Gray observes, " that whatever 

 greater part of the load is placed before the centre of gravity, which is always in the axle, 

 must rest constantly on the horse that is in the shafts. In going down hill this burden 

 must be considerably increased, especially if the load be high above the centre of the 

 axle, or the descent steep ; and the additional burden upon the shaft-horse is always in 

 proportion to these two causes united. But there is another disadvantage ; for, unless 

 the line of the draught of the foremost horse be exactly in the line from the hook of his 

 collar to the centre of the axle (which is hardly possible), he will perpetually be pulling 

 down the liindmost horse, or, in other words, M'ill be giving him more weight to carry. 

 For, as the traces of the foremost horse are generally fixed upon the shafts, this throws 

 his line of draught at a considerable angle above the centre of the axle ; from which it is 

 evident, that although the road be ever so level, yet in every double or two-horse cart, 

 the foremost horse must either not draw at all, or must bring additional weight upon the 

 horse in the shafts, which weight will always be in proportion to the force with which 

 the trace-horse di-aws, and the largeness of the angle which the line of his draught makes 

 with the line from the hook of his collar to the centre of the axle. Besides, unless the 

 driver be more careful than ordinary, and keep the trace-horse to his duty, the other one 

 has not only this great weight to carry, but also the whole load to draw. The angle is 

 increased considerably when the trace-horse is of a lower size than the one in the shafts, 

 which may frequently happen ; and, by this means, a still greater burden is laid upon 

 the back of the horse employed in the shafts. 



2755. Improved two-horse carts. (Jig. 386.) It may be suggested to those who arc 

 fond of employing two-horse carts, that, in order to adjust the traces of the fore-horse 



