lS5 French Kathnal h-Jlitufe. 



cities : if two or more fubflances, then, which eater Into an^* 

 mixture, are of fuch a nature as to produce an elaftic, con- 

 crctCj or even infoluble compound, we niuft no longer cal- 

 culate their effect in the definitive refiilt according to the ab- 

 folute affinity belonging to each, but niuft deduft what 

 this concrete or elaftic ilate takes from the affinity. It may 

 readily be perceived what light the application of thefe prin- 

 ciples, which have never been before confidered in their ge- 

 neral extent, mull throw upon all the phenomena of che- 

 miftry. 



C. Berthollet, by means of thefe principles, has been able 

 to bring under the common laws of chemiftry a multitude of 

 fafts which feemed infulated, or even contrary to thefe laws. 

 Hitherto, for example, the affinities of the greater part of 

 thefe compound bodies were confidered independently of 

 thefe of their compounds, becaufe the circumftances above 

 mentioned were not taken into account. C. Berthollet 

 clearly fhows that in many cafes they depend on each other j 

 and how, from fo fmall a number of elementary fubftances, 

 when chemically confidered, fo many compounds, and effects 

 fo various as thofe exhibited by Nature, can be produced. 



Befides the table before mentioned, C. Guyton has pre- 

 fented to us four others, deftined, like the firft, for the in- 

 firuAion of the pupils in the Polytechnic School. One of 

 them contains a methodical didribution of minerals into 

 orders, claffiis, genera, and fpecies. Another gives a com- 

 plete fyftem of the external charadler of minerals according 

 to the principles of Verner, with additions. The ob)e4t of 

 the third and fourth is, to facilitate to beginners Haiiy's 

 theory of theftruftureof cryflals, by prefenting in a feries the 

 firll molecule of a cryftal, its nucleus, and the diffi:;rent mo- 

 difications produced by the laws of decrement, and by givincf, 

 according to the graphic method, a key to the formula which 

 reprefcnt thtfe modifications, and the folids refulting from 

 them, without lofinrr fight of the nucleus. 



Some of the naturalifts of the Clafs have employed them^ 

 felves, during the lafi quarter, on the remains of organifed 

 bodies difcovered in places where living animals analogous 

 to them do not at prefent cxift. 



C. Villar?, 



i 



