THE COPLEY MEDALIST OF 1871 457 



bj tlie combustion of tbe tree. The beat and work poten- 

 tial in our coal strata are so mucb strengtb witbdrawn 

 from tbe sun of former ages. Mayer lays tbe axe to tbe 

 root of tbe notions regarding ** vital force,'* wbicb were 

 prevalent wben be wrote. Witb tbe plain fact before us 

 tbat in tbe absence of tbe solar rays plants cannot per- 

 form tbe work of reduction, or generate cbemical tensions, 

 it is, be contends, incredible tbat tbese tensions sbould be 

 caused by tbe mystic play of tbe vital force. Sucb a by- 

 potbesis would cut off all investigation ; it would land us in 

 a cbaos of unbridled fantasy. "I count,'* be says, ''tbere- 

 fore, upon your agreement witb me wben I state, as an 

 axiomatic trutb, tbat during vital processes tbe conversion 

 only, and, never tbe creation of matter or force occurs." 

 Having cleared bis way tbrougb tbe vegetable world, 

 as be bad previously done tbrougb inorganic nature, 

 Mayer passes on to tbe otber organic kingdom. Tbe 

 pbysical forces collected by plants become tbe property 

 of animals. Animals consume vegetables, and cause tbem 

 to reunite witb tbe atmospberic oxygen. Animal beat is 

 tbus produced; and not only animal beat, but animal mo- 

 tion. Tbere is no indistinctness about Mayer bere; be 

 grasps bis subject in all its details, and reduces to figures 

 tbe concomitants of muscular action. A bowler wbo im- 

 parts to an 8-lb. ball a velocity of 30 feet, consumes in 

 tbe act JO of a grain of carbon. A man weigbing 150 

 lbs., wbo lifts bis own body to a beigbt of 8 feet, con- 

 sumes in tbe act 1 grain of carbon. In climbing a moun- 

 tain 10,000 feet bigb, tbe consumption of tbe same man 

 would be 2 oz. 4 drs. 50 grs. of carbon. Boussingault 

 bad determined experimentally tbe addition to be made 



to tbe food of borses wben actively working, and Liebig 



Science— Y— 20 



