APPENDIX II. 141 



temperature of an equal weight of water 1 C. If 

 this weight were let fall from a height of 425 

 metres, its collision with the earth would produce 

 an amount of heat sufficient to raise the temperature 

 of 1 kilogram of water 1 C. The same heating 

 effect would also of course be produced by the fall 

 of 425 kilograms through 1 metre. This standard 

 of force is termed a metrekilogravfr ;* and 425 metre- 

 kilograms are equal to that amount of heat which is 

 necessary to raise the temperature of 1 kilogram of 

 water through 1 C. If then it be found that 

 the heat evolved by the combustion of a certain 

 weight of charcoal or muscle, for instance, raises 

 the temperature of 1 kilogram of water through 

 1 C., this means, when translated into mechanical 

 power, 425 metrekilograms. Again, if a man 

 weighing 64 kilograms climbs to a height of 1,000 

 metres, the ascent of his body to this height re- 

 presents 64,000 metrekilograms of work; that is, 

 the labour necessary to raise a kilogram weight to 

 the height of 1 metre 64,000 times. 



In order to estimate the amount of actual energy 

 generated by the oxidation of a given amount of 

 muscle in the body, it is necessary to determine, 

 first, the amount of actual energy generated by the 

 combustion of that amount of muscle in oxygen, and 

 then to deduct from the number thus obtained the 

 amount of energy still remaining in the products of 

 the oxidation of this quantity of muscle which leave 

 the body. Of these products, urea and uric and 



* I follow the example of the Registrar-General in abbre- 

 viating the French word gramme to gram. 



