CARBON IN THE LABOUR DIET OF MAN. 511 



horse in a day, it appears that the difference between the 

 energy corresponding to the combustion of the carbon in the 

 flesh-formers of the diet of rest and that of the carbon in the 

 flesh-formers of the work-diet, approximates to that number. 

 On the assumption, then, that our typical diet of the horse at 

 rest and that of the horse under work is correct, we have the 

 means of determining the fitness of other dietaries for the 

 horse without reference to the nitrogen separated from the 

 system along with the urinary products. 



A greater degree of accuracy will be obtained if one-seventh 

 part of the whole carbon in the flesh-formers be deducted, as 

 corresponding to the proportion of the carbon of the solids 

 carried off in urea and the other urinary compounds. 



When the estimate of the ordinary severe labour of man 

 made by Professor Playfair, 792,000 foot-pounds in a day, is 

 tried by its correspondence with the amount of carbon burnt 

 with oxygen, it is found to answer to no more than 1.15 oz. 

 of carbon. This quantity answers to 2.21 oz. of flesh -form- 

 ers, which, being joined to the amount of flesh - formers 

 (2.06 oz.) required simply to sustain life, gives no more than 

 4.27 oz. of flesh-formers. These numbers are brought out 

 thus : 



792,000 foot-pounds. 

 792,000 



= 1026 Ib. of water raised one degree Fahrenheit. 

 16 = 16,416 oz. do. 

 = 1.15 oz. of carbon burnt in raising 16,416 oz. 



14,200 



of water one degree Fahrenheit. 



The total amount of carbon in this subsistence-diet of man 

 is, in round numbers, 7.5 oz., while it may be called 15 oz. 

 in his full-labour diet. The first quantity yields a total daily 

 energy in the system equal to 5,138,432 foot-pounds the 



