On the Reduction of Horse Labour by sin(jle Carts. 81 



as m H H H Hy and the area of pressure the triangle Dnn, 

 together with its centre e, is the same quantity, but the bulk 

 being placed below the axle, the pressure is found on the upward 

 side of the plumb-line and reversed, and acts through its arc in 

 inverted proportion, on the underneath side of the continuation 

 of the lever D A at oj). 



In the combined bulk above and below the axle H H N N 

 (see Fig. 5) is exhibited an equilibrium which cannot be dis- 

 turbed, the quantities on each side of the plumb-line are seen to 

 be the same, and will always be so on every inclination, as what- 

 ever portion of the bulk above the axle passes the plumb-line 

 with a downward pressure, an equal portion below the axle passes 

 upwards, which is declared by the two equal angles formed by 

 the line perpendicular to the inclined plane intersecting the 

 plumb-line at the axle. 



There is a simple remedy for pressure used in the North, and 

 by my own people, and I dare say by all occasionally who are 

 experienced in the use of carts — that of stopping at the top of a 

 hill to raise the shafts by shortening the back-chain and lengthen- 

 ing the breast-band, and returning them to their places at the 

 bottom. The full extent of this may raise the shaft 1 foot at 

 this point. Here the short cart has an advantage over the long 

 one ; for its length from the axletree to the back chain not being 

 more than about 9 feet, it might obtain an equilibrium in a 

 descent of 1 in 9, while the harvest cart being 12 feet between 

 the same points, would only obtain it in a descent of 1 in 12. 



While so much has been urged on the apparent necessity for 

 an equilibrium, it must not pass unobserved that practice requires 

 the placing a certain portion of weight on the horse. We find 

 cartwrights adjusting their cart -bodies on the axle with some re- 

 gard to this view ; and in the Cumberland cart it occurs to an 

 extent that I cannot fully account for, considering the nature of 

 the country. 



Where skidding is necessary, a presser on the principle of the 

 common French plan might be the most desirable. The carriers 

 on the Oxfordshire chalk hills use a flat piece of board 2 or 3 feet 

 square, trailing on the ground behind by a chain or rope from 

 the middle of the axletree ; on this they stand, and by their own 

 weight give an effectual check to the load. Tipsticks, on which 

 the load is tilted for this purpose, as well as everything else of 

 the kind that injures a public road, are forbidden by the Turn- 

 pike Act. 



One more view of this part of my subject must be taken before 

 I proceed to a few practical details. It may be observed that if 

 the adoption of the one-horse system be essential, why not adapt 

 to one animal a light waggon instead of a cart, when the matter 



VOL. II. G 



