REAUMUR. 187 



are unquestionable, and yet there is even more of 

 novelty and interest in those which he made in na- 

 tural history. For instance, he explained the means 

 by which many shells, sea-stars, and other mollusca 

 or zoophytes, execute their progressive motion. He 

 likewise illustrated the curious manner in which 

 the claws of crabs and lobsters are reproduced. He 

 also threw a new light on the singular action of 

 the torpedo, and the organ by means of which it is 

 exercised, although thephenomena of electricity were 

 not then sufficiently understood to enable him to 

 perceive all the relations of his subject. In 1718, he 

 published a memoir on the rivers of France, w hich 

 contain grains of gold in their sands, and soon 

 after described the immense beds of fossil shells 

 known in Touraine under the name oi faluri. In 

 1723, he made observations on the lustre emitted by 

 several kinds of shell-fish, especially the pholades, 

 which perforate wood and stones. 



Physiology is indebted to him for the ingenious 

 and decisive experiments w'hich, in 1752, made 

 known the difference that exists, with respect to 

 digestion, between birds of prey, whose stomach acts 

 on their food only by means of a solvent fluid, 

 and granivorous birds, in which a very powerful 

 muscular gizzard exercises a pressure sufficient to 

 break down the hardest bodies and reduce them to 

 powder. 



These labours might well have sufficed for a 

 single life ; but the most remarkable undertaking 

 of Reaumur has not yet been mentioned. It is 

 entitled Memoires pour servir a THistoire des In- 

 sectes, and extends to six quarto volumes, which 



