LAVOISIER. 231 



with M. Guettard; and he had collected materials for an 

 extensive work on the revolutions of the globe, when the 

 recent progress of another science gave a new direction 

 to his pursuits. His paper on gypsum contains a num- 

 ber of experiments, which shew it to be a neutral salt, 

 soluble in a great proportion of water, and composed of 

 sulphuric acid united to a calcareous base. This and 

 almost every other part of his paper was well known 

 before. M. Montigny had, in the ' Memoirs of the Aca- 

 demy/ 1762, shewn its solubility, and M. Margraaff, in 

 the 'Berlin Memoirs/ as far back as 1750, had proved 

 both this and its composition. M. Lavoisier refers to 

 these long-published works in a note appended to his 

 paper, but states that he had not seen MargraafFs till 

 after his own was read before the Academy. He also 

 states that M. Baume had published researches similar to 

 his in a journal, but that he was not aware of this till he 

 had made considerable progress with his paper. It is 

 unfortunate that this eminent person should have begun 

 his works with this kind of doubt hanging over his ori- 

 ginality. Yet we may observe that his paper contains an 

 ingenious theory, explaining the phenomenon of the for- 

 mation of gypsum on the principles of ordinary crystal- 

 lization; and that he has also ascertained the proportion 

 of water required for its solution more accurately than 

 had before been done ; that he gave a systematic view of 

 the whole subject. Quatis ab incept o processerat It is 

 remarkable that all the distinguishing characters of his 

 inquiries in after-times should be found to mark this 

 his first production. We observe the same disputed 

 originality in his experiments, the same anticipation of 

 his discoveries by former inquirers, the same superiority 



