BLACK. 329 



occurred in 1752. A third note follows, and proves 

 him to have now become possessed of the true theory of 

 causticity, namely, the expulsion of air, and of mildness, 

 namely, its absorption. The discovery was therefore 

 made as early as 1752 it was published generally in 

 1754 it was given in its fullest details in 1755. At 

 this time M. Lavoisier was a boy at school nine 

 years old when the discovery was made eleven when 

 it was published twelve when it was as fully given 

 to the world as its author ever delivered it. No pos- 

 sibility therefore existed of that great man finding out 

 when he composed his great work that it was a 

 discovery of his own, as he did not scruple to describe 

 oxygen, though Dr. Priestley had first communicated it 

 to him in the year 1774 ; or that Black and he dis- 

 covered it about the same time, as he was in the habit 

 of stating with respect to other gases, with a con- 

 venient degree of ambiguity just sufficient for self- 

 defence, should he be charged with unfair appropriation. 

 Who that reflects on the noble part which this great 

 philosopher acted, both in his life and in his death, can 

 avoid lamenting that he did not rest satisfied with the 

 fame really his due, of applying the discoveries of others, 

 in which he had no kind of share, to the investigation 

 of scientific truths, as entirely the result of his 

 extraordinary faculty of generalization, and genius for 

 philosophical research, as those discoveries, the mate- 

 rials of his induction, were the undivided property of 

 others ! 



The capital discovery of Black, thus early made, and 

 to any share in which no one has ever pretended, was 

 that the causticity, as it was formerly termed upon a 



