512 PHYSIOLOGY AT THE FARM. 



second, 9,795,136 foot-pounds ; or reference may be made to 

 these as respectively 5 millions and 10 millions of foot-pounds, 

 brought out thus : 



7.5 X 14,200 = 106,500 oz. of water raised to one 

 degree Fahrenheit. 



. 6656 lb . do . 



6656 X 772 5, 138,432 foot-pounds. 

 15 x 14,200 = 213,000 oz. of water raised to one 

 degree Fahrenheit. 



= 13,312 lb. of water do. 



13,312 X 772 = 10,276,864 foot-pounds. 



Thus the difference between the total energy in a horse 

 under work-diet and the total energy in a man under work- 

 diet is 110,309,5369,795,136; one hundred and ten mil- 

 lions of foot-pounds to ten millions of foot-pounds ; so that 

 probably the available energy of a horse is eleven times greater 

 than that of a man. 



" If, again," Professor Playfair resumes, "we take two labour- 

 ing animals of the same herbivorous nature the ox and the 

 horse we can compare their labour and food without compli- 

 cating the question by deducting the quantity required for the 

 opus vitale. Experience shows," he continues, " that an ox is 

 well fed on 50 lb. of mangold- wurzel, 3 lb. of beans, and 17 

 lb. wheaten straw, the flesh-formers in this food being 38.6 oz. 

 Muschek has given us the labour of an ox, from which we 

 obtain the following ratios : 



Work of horse in foot-pounds, ) 12,400,000 



"Work of ox in do., J 8,640,000 



Plastic food of horse, ) 56.5 



> ^r 1 d-f) * 



Plastic food of ox, J 38.6 



* Lecture, pp. 20, 21. 



- 1.43 



