4 BLACK. 



would possibly, like his other original speculations, 

 never have been given by himself to the press. 



Upon taking his degree at Edinburgh College he 

 wrote and published a Latin Thesis, after the manner 

 of that as well as the foreign universities. The subject 

 was ' Magnesia, and the Acid produced by Food in the 

 Stomach' (De Acido e Cibis orto; et de Magnesia), and 

 it contained the outline of his discoveries already made. 

 Having sent some copies of this Thesis to his father at 

 Bordeaux, one was given to Montesquieu, who at once 

 saw the vast importance of the truths which it unfolded. 

 He called a few days after and said to Mr. Black, " I 

 rejoice with you, my very good friend : your son will 

 be the honour of your name and of your family." But 

 though the discoveries were sketched distinctly enough 

 in this writing, they were only given at large the fol- 

 lowing year in his celebrated work * Experiments on 

 Magnesia, Quicklime, and other Alkaline Substances/ 

 incontestably the most beautiful example of strict in- 

 ductive investigation since the 4 Optics' of Sir Isaac 

 Newton. His fervent admiration of that masterly work 

 was indicated by his giving it to Professor Robison, 

 then a student, and desiring him to " make it the model 

 of all his studies," recommending him at the same time 

 a careful study of the mathematics. It appears that 

 this important inquiry concerning the alkaline earths, 

 the results of which were destined to change the face 

 of chemical science, was suggested by the attempts 

 then making to find a solvent for the stone. I dis- 

 tinctly recollect Dr. Black, in his lectures, prefacing 

 the admirable and most interesting account which he 



fave of his discoveries, with the statement that the 

 opes of finding a solvent which should not, like the 

 caustic alkalies, destroy the substance of the bladder 

 in melting the stone, first led him to this investigation. 

 Professor Robison has given a note from his memo- 

 randum-book indicating that he had at first fallen into 

 the notion of alkalies, when treated with quicklime, 



