BEGINNINGS OF MODERN CHEMISTRY 



after reviewing the evidence carefully in 1833, decided 

 in favor of Watt. 



It appears that something like a year before Caven- 

 dish made known his complete demonstration of the 

 composition of water, Watt communicated to the 

 Royal Society a suggestion that water was composed 

 of " dephlogisticated air (oxygen) and phlogiston (hy- 

 drogen) deprived of part of its latent heat." Caven- 

 dish knew of the suggestion, but in his experiments re- 

 futed the idea that the hydrogen lost any of its latent 

 heat. Furthermore, Watt merely suggested the possi- 

 ble composition without proving it, although his idea 

 was practically correct, if we can rightly interpret the 

 vagaries of the nomenclature then in use. But had 

 Watt taken the steps to demonstrate his theory, the 

 great "Water Controversy" would have been avoided. 



Cavendish's report of his discovery to the Royal 

 Society covers something like forty pages of printed 

 matter. In this he shows how, by passing an electric 

 spark through a closed jar containing a- mixture of 

 hydrogen gas and oxygen, water is invariably formed, 

 apparently by the union of the two gases. The ex- 

 periment was first tried with hydrogen and common 

 air, the oxygen of the air uniting with the hydrogen to 

 form water, leaving the nitrogen of the air still to be 

 accounted for. With pure oxygen and hydrogen, how- 

 . Cavendish found that pure water was formal, 

 slight traces of any other substance which 

 mi^ht not be interpreted as being chemical impurities. 

 There was only one possible explanation of this phe- 

 nomenon that hydrogen and oxygen, when combined, 

 form water. 



15 



