v.] CHEMICAL ENERGIES. 49 



destroyed, or neutralized, or cancelled each other ; and this 

 statement is true, but it is not the whole account of what 

 takes place. It does not tell what has become of the 

 energy due to the motions that have disappeared. This 

 energy, however, has been transformed into heat. Just in 

 the same way, when we say that water is formed by the com- 

 bination of oxygen and hydrogen, this statement is true, 

 but it is not the whole account of what takes place. In 

 order to give a full account of it, we must say that water 

 is formed by the combination of oxygen and hydrogen, 

 and the liberation of a definite quantity of energy in the 

 form of heat. Energy is as real as matter, and the libera- 

 tion of the energy is as essential a part of the process as 

 the combination of the oxygen and hydrogen. 



Though the facts of chemical dynamics which I have 

 stated are universally recognised as true, I am not sure 

 that their importance is yet in general sufficiently felt, 

 even by scientific men. I proceed to submit the plan 

 of an addition to the chemical notation in general use, 

 which would, I believe, give them no more than their 

 due prominence. 



In the preceding part of tliis chapter, I have endeavoured 

 to make the subject intelligible to any person of ordinary 

 intelligence, who is willing to give it the needful attention. 

 In what foUows, on the contrary, it is necessary for me 

 to presume on the reader's acquaintance with chemical 

 notation. 



When two substances spontaneously unite and form a 

 compound, as for instance when a volume of hydrogen 

 unites with haK a volume of oxygen to form a volume of 

 watery vapour, we write the symbol of the compound in Chemical 

 such a form as this : (I use the new notation, in which the expressive 

 equivalents of all substances, when in the gaseous or of combi- 

 vapoury state, are supposed to have equal volumes :) — 



HOJ; 



and this is a true statement, but it does not state the 

 whole of what takes place ; for it tells nothing about the 

 energy which, in the act of combination, is transformed 



E 



