6^8 HORSE-SHOES AND HORSE-SHOEING. 



ment communicated to these 57,000 kilogrammes repre- 

 sents an expenditure of power employed by the motor 

 without any useful result ; and as the motor is a living 

 one, this expense of strength represents an exhaustion, or 

 if you like it better, a degree of fatigue, proportioned to 

 the effort necessary for its manifestation. This calcula- 

 tion is most simple and readily understood. It is to be 

 noted, nevertheless, that I have omitted a considerable 

 fact : which is, that the weights I have tabulated are situ- 

 ated at the extremities of the limbs, and that the arms of 

 the levers on which the muscles act to raise them, being 

 infinitely shorter than those of the physiological resistance 

 to which these weights are added, the intensity of their 

 action ought, therefore, to be singularly increased. But 

 to measure this intensity of action would require a mathe- 

 matical aptitude which I do not possess. I will not, there- 

 fore, dwell on this point, notwithstanding its importance, 

 and am content to signalize it. Otherwise, the figures I 

 present speak for themselves, and tell us that the diminu- 

 tion in the weight of horse-shoes is not an accessory con- 

 sideration, so far as the useful application of the horse's 

 strength goes.' 



It will be seen that this question of weight at the 

 lower end of the limb is a serious one ; the power moving 

 it acting at the upper extremities, and having but short 

 leverage. We can readily imagine what a difference in 

 power must be required to move a pound at the fore-arm 

 or knee, and at the lower surface of the foot, and how 

 much the lightening of a shoe by one or two ounces 

 must affect the motion of the limb. 



In shoeing, this important consideration has been 



