16 ESSAYS BIOGRAPHICAL AND CHEMICAL 



thereof is extricated, that some naturalists have suspected 

 it to be altogether destitute of elasticity, when thus 

 combined with other principles in the composition of 

 bodies.' 



After describing some of the physical properties of 

 water, Macquer continues : ' Water enters into the texture 

 of many bodies, both compounds and secondary principles ; 

 but, like air, it seems to be excluded from the composi- 

 tion of all metals and most minerals. For although an 

 immense quantity of water exists in the bowels of the 

 earth, moistening all its contents, it cannot be thence 

 inferred that it is one of the principles of minerals. It 

 is only interposed between their parts ; for they may be 

 entirely divested of it, without any sign of decomposition : 

 indeed, it is not capable of an intimate connection with 

 them.' 



Of earth he says : ' We observed that the two principles 

 above treated of are volatile ; that is, the action of fire 

 separates them from the bodies they help to compose, 

 carrying them quite off and dissipating them. That of 

 which we are now to speak, namely earth, is fixed, and 

 when it is absolutely pure, resists the utmost force of fire. 

 So that, whatever remains of a body, after it has been 

 exposed to the power of the fiercest fire, must be con- 

 sidered as containing nearly all earthy principle, and 

 consisting chiefly thereof.' ' Earth, therefore, properly so 

 called, is a fixed principle which is permanent in the fire.' 

 He then goes on to distinguish between fusible or vitrifi- 

 able earths, and infusible or unvitrifiable earths, the latter 

 of which are also called absorbent earths, from their pro- 

 perty of imbibing water. 



Maquer's views regarding fire are as follows : ' The matter 

 of the sun, or of light, the Phlogiston, fire, the sulphureous 

 principle, the inflammable matter, are all of them names 

 by which the element of fire is usually denoted. But it 



