Conservation of Energy 13 



well-known concomitants of chemical action. 

 Hence we infer that heat, electricity, mechanical 

 motion, and chemical action are a few among 

 many other different kinds of one distinct 

 entity-energy. 1 



Observation has shown : 



I. That one form of energy can be trans- 

 formed directly or by intermediate steps into 

 any other form. 2 



II. When any quantity of one form of 

 energy is made to disappear, an equivalent 

 quantity of another form or forms of energy 

 reappear. 



III. We recognise energy in two forms : 

 Kinetic free or available, and Potential or 

 possible energy; the first depends on motion, 

 the second on the position of the body under 

 consideration. Thus, when a marble is set roll- 

 ing, it has the power in virtue of its motion of 

 changing the state of motion of any other 



1 Text Books of Physical Chemistry, edited by Sir William 

 Ramsay. Volume on Chemical Statics ana Dynamics, by J. W. 

 Mellor, D.Sc., p. 21. 



2 "The mechanism by means of which stimulating waves are 

 converted into heat in the body acted on is still a mystery. That 

 waves should cause the electrons to vibrat- is perfectly clear, but 

 how vibrations of the electrons are converted into those vibrations 

 of the atonu and molecule - which constitute heat is still unsolved." 

 P. Phillips on Radiation, p. 57. 



