47 



Mr. Desmarest's induction in this case, and which is per- 

 petually adopted by those of his school, is short and clear. 



He first assumes, that basalt is the effect of igneous fusion ; 

 and then it must be granted to him, that he may model these 

 fires, so as to answer the end. 



His successors have, in stating this argument, a great ad- 

 vantage over Mr. Desmarest ; for, while he is obliged to get 

 over his whole difficulty, by one grand postulate, they have 

 the benefit of his authority; and quote him, like another 

 Aristotle, ipse dixit. 



A new difficulty occurred to Mr. Desmarest, which he 

 does not avow, until he publishes his second Memoir. No 

 doubt, emboldened by the great success of his first, he now 

 discovers, that his theory cannot be overturned by any facts, 

 however hostile to it; and, that his credit is so well esta- 

 blished, that the world will implicitly receive any reason, he 

 shall think proper to assign, for the most anomalous facts. 



He found, as he admits, horizontal strata (couches) of 

 argil and limestone, incumbent on his basaltic lavas. These 

 materials are not volcanic productions; yet Mr. Desmarest 

 must account for their being found in this unexpected situ- 

 ation, which he does, lightly and easily. He says, " these are 

 " (pour ainsi dire) a superfcctation, posterior to the lavas:" that 

 is, he throws alma 7nater tellus into labour again, delivers her 

 of two or three strata; which, happening to be placed over 

 his lavas, fully account for every thing. 



With this ingenious and philosophical solution of his last 

 difficulty, Mr. Desmarest completes the sum of the argu- 



c 2 ments. 



