THE COPLET MEDALIST OF 1871. 329 
by the wave-motion of the sun is changed into the rigid 
form of chemical tension, and thus prepared for future 
use. With this prevision, as shall subsequently be shown, 
the existence of the human race itself is inseparably con- 
nected. It is to be observed that Mayer's utterances are 
far from being anticipated by vague statements regarding 
the " stimulus" of light, or regarding coal as " bottled 
sunlight." He first saw the full meaning of De Saussure's 
observation as to the reducing power of the solar rays, and 
gave that observation its proper place in the doctrine of 
conservation. In the leaves of a tree, the carbon and 
oxygen of carbonic acid, and the hydrogen and oxygen of 
water, are forced asunder at the expense of the sun, and 
the amount of power thus sacrificed is accurately restored 
by the combustion of the tree. The heat and work 
potential in our coal strata are so much strength with- 
drawn from the sun of former ages. Mayer lays the axe to 
the root of the notions regarding " vital force "which 
were prevalent when he wrote. With the plain fact before 
us that in the absence of the solar rays plants cannot per- 
form the work of reduction, or generate chemical tensions, 
it is, he contends, incredible that these tensions should be 
caused by the mystic play of the vital force. Such an 
hypothesis would cut off all investigation; it would laud us 
in a chaos of unbridled fantasy. "I count," he says, 
" therefore, upon your agreement with me when I state, as 
an axiomatic truth, that during vital processes the conver- 
sion only, and never the creation of matter or force 
occurs." 
Having cleared his way through the vegetable world, as 
he had previously done through inorganic nature, Mayer 
passes on to the other organic kingdom. The physical 
forces collected by plants become the property of animals. 
Animals consume vegetables, and cause them to reunite 
with the atmospheric oxygen. Animal heat is thus pro- 
duced; and not only animal heat, but animal motion. 
There is no indistinctness about Mayer here; he grasps his 
subject in all its details, and reduces to figures the con- 
comitants of muscular action. A bowler who imparts to 
an 8-lb. ball a velocity of thirty feet, consumes in the act 
one-tenth of a grain of carbon. A man weighing 150 Ibs., 
who lifts his own body to a height of eight feet, consumes 
in the act one grain of carbon. In climbing a mountain. 
