252 DRAUGHT AND IIAENESS. 



other end of cylinder has a movable bottom and is 

 fitted with a loop or ring. The interior of the 

 cylinder contains rings of India-rubber, such as are 

 used for gas and steam checks, and thin metal discs 

 perforated in the centre with a | in. to h inch opening 

 placed alternately, a ring coming next to the fixed 

 bottom of the cylinder and a disc at the other end of 

 the column as it may be termed. 



The iron rod, already mentioned, has one of its ends 

 fitted with or shaped like a draught-hook. The rod 

 passes through the hole in the fixed bottom of the 

 cylinder, leaving the hook projecting, and up through 

 the centres of the rings and metal discs resting on the 

 topmost of these latter by means of a key, the whole 

 is completed when the movable bottom is fixed into the 

 cylinder. There is no difficulty in understanding how 

 this contrivance acts. If, for instance, a pair of them 

 be attached by their rings to the draught hooks of a 

 vehicle and by their hooks to the trace of a harnessed 

 horse, the animal will exert its strength against the 

 elastic column of rings and discs inside the cylinder, in- 

 stead of immediately against the rigid frame of the 

 vehicle. Overcoming the resistance easily at first it does 

 not have recourse to a violent plunge into the collar, 

 and by the time the rod has begun to compress the 

 india-rubber rings into a state of rigidity, the vehicle, 

 if not loaded out of proportion to the number of horses 

 attached, will have began to move, in fact the action 

 will have been brought to resemble the steady push of 

 a draught ox, and will have lost its jerky character to 

 the great comfort of the horse's shoulders, necks, and 

 legs, and to the saving of the harness and carriages. 



But it is not alone in saving of power and the di- 

 minishing of wear and tear, in starting vehicles from 



