98 THE MECHANISM OF LIFE 



Tout se metamorphose entre ses mains actives; 

 Partout le mouvement incessant et divers, 

 Dans le cercle eternel des formes fugitives, 

 Agitant I'immense univers." 



It was onlv towards tlie middle of last century that mankind 

 in the long search after unity in nature began to realize that all 

 the movements of the universe are the manifestations of a single 

 agent, which we call energy. In reality all the phenomena of 

 nature may be conceived as diverse forms of motion, and the word 

 " energy " is the common expression applied to all the various 

 modes of motion in the universe. It was by the study of heat, 

 and more especially of thermodynamics, that we obtained our 

 conceptions of the science of energetics. 



It was in Munich in 1798 that the English engineer Count 

 Rumford first observed that in the operation of boring a cannon 

 the copper was heated to such a degree that the shavings 

 became red-hot. This suggested his famous experiment, in 

 which a heavy iron pestle was turned by horse power in a 

 metal mortar filled with water. The water boiled, and when 

 more water was added this also became heated to ebullition, 

 and so on indefinitely. Rumford argued that the heat thus 

 obtained in an indefinite quantity could not be a material 

 substance ; that motion was the only tiling added to the 

 water without limit, and that therefore heat must be 

 motion. 



While Rumford's experiment showed the transformation of 

 motion into heat, the steam engine was soon afterwards to 

 demonstrate the opposite transformation, viz. that of heat 

 into motion. 



The actual state of our knowledge with regard to the 

 science of energy rests on two principles, that of Mayer and 

 that of Garnot. 



The first principle was defined by J. R. Mayer, a medical 

 practitioner of Heilbronn, whose work, Bemerkungen neb. 



er 



die Kriifte der unbelebten Natur, was published in 18452. "All 

 physical phenomena," says Mayer, "whether vital or chemical, 

 are forms of motion. All these forms of motion ate susceptible 

 of change into one another, and in all the transformations the 



