BEGINNINGS OF MODERN CHEMISTRY 



chalk was precipitated, thus proving that carbonic acid 

 was being constantly thrown off in respiration. 



The effect of Black's discoveries was revolutionary, 

 and the attitude of mind of the chemists towards gases, 

 or " airs," was changed from that time forward. Most 

 of the chemists, however, attempted to harmonize the 

 new facts with the older theories to explain all the phe- 

 nomena on the basis of the phlogiston theory, which 

 was still dominant. But while many of Black's dis- 

 coveries could not be made to harmonize with that 

 theory, they did not directly overthrow it. It re- 

 quired the additional discoveries of some of Black's 

 fellow-scientists to complete its downfall, as we shall 

 see. 



HENRY CAVENDISH 



This work of Black's was followed by the equally 

 important work of his former pupil, Henry Caven- 

 dish (1731-1810), whose discovery of the composition 

 of many substances, notably of nitric acid and of 

 water, was of great importance, adding another link 

 to the important chain of evidence against the phlogis- 

 ton theory. Cavendish is one of the most eccentric 

 figures in the history of science, being widely known in 

 his own time for his immense wealth and brilliant in- 

 tellect, and also for his peculiarities and his morbid 

 sensibility, which made him dread society, and prob- 

 ably did much in determining his career. Fortunately 

 for him, and incidentally for the cause of science, he 

 was able to pursue laboratory investigations without 

 being obliged to mingle with his dreaded fellow-mortals, 

 his every want being provided for by the immense fort- 

 une inherited from his father and an uncle. 



