On Tribasic Phosphoric Acid. 109 



I must mention here the names of several chemists, who about 

 this time rendered important services to their science, without, 

 however, coming to any definite and important results as to 

 phosphoric acid. They were: 



H. Davy (horn 1778, died 1829). 



Oronstedt (born 1722, died 1765). 



Bergmann (born 1735, died 1784), who in 17*", in a paper 

 " on the analysis of minerals in the wet way," made known 

 certain laws of combination, which, together with Proust's 

 publications on the same subject, must be considered the tore- 

 runners of the great essay of Berzelius (born 177'.', died l x t8) 

 which was published in 1810, " Essay to find th< fix< d and sim- 

 ple proportions, according to which the constituents <if [nor- 

 ganic naturt are supposed to enter into combination." 



Before speaking, however, of this great man and his works, 

 1 have to mention — 



Scheele (born 1742, died L786), who, with a rare talent for 

 observation and acuteness of reasoning, an ornament of his 

 country and of his times, was remarkable in the highest degree 

 for the many and important discoveries which he made with 

 comparatively very few expedients. Scheele and Priestley 

 (born 1733, died 1801) must, together with Lavoisier (born 

 1713, died 1794), be considered the discoverers of oxygen, and 

 the founders of modern chemistry. 



The discovery of oxygen, in 1771, introduced the balance into 

 the laboratory, and a new field was opened to the inquiring 

 student of nature. The importance of this step was, how- 

 ever, not immediately recognized, and the century passed 

 away before the chemists of that time understood the laws 

 that govern the combination of atoms. And although the 

 tendency of any age to some great result is fell by all, 

 there may he only one man living who understands it. 

 and is gifted with the power to achieve it and give it, ex- 

 pression. I -was actuated with feeling- of the sort in read- 

 ing the journals published in thoBedaySj and which contained 



