Observations on the Nature and Importance of Geology, 293 



the precipitate which formed in the water became so consider- 

 able, that M. de S. deemed it proper to intermit the use of the 

 powder, and sent for some more, promising to inform me on 

 his return from Italy, of what, according to his expression, 

 had happened. M. de S. returned at the end of six months, 

 and sent me back the powder in question, which I submitted 

 to the following experiments. 



1st, This powder put into a quantity of cold water, double 

 that which is necessary for dissolving the two salts, rendered it 

 milky. 



% Dissolved in a large quantity of water, it deposited a white 

 powder, which, on being washed several times and dried, was 

 found to be subcarbonate of magnesia. 



The liquor in which this deposit was formed was limpid after 

 being filtered, and was not rendered turbid, either cold or hot, 

 by the soluble alkaline subcarbonates. All the acids stronger 

 than the carbonic disengaged this latter from it. Lastly, when 

 suitably evaporated, sulphate and carbonate of soda were obtain- 

 ed, part of the latter of which was in the form of subcarbonate. 

 To explain here the presence of the carbonate of soda, it requires 

 to be known that the quantity of bicarbonate mixed with the 

 sulphate 6f magnesia, was more than sufficient to decompose 

 this latter salt. 



There results from this observation., that the sufficiently pro- 

 longed contact ofsidphate of magnesia and bicarbonate of soda in 

 a dry state, determines a chemical action similar to that which 

 the concurrence of water and heat would produce, affording a 

 new example of the inaccuracy of the old chemical axiom : Cor- 

 pora non agunt nisi soluta. — Journal de Pharmacie, March 

 1826. 



Observations cni the Nature and Importance of Geology. 



XJL CELEBRATED school of philosophy among the ancients, main- 

 tained that there was only one virtue. With as much, nay even 

 more, propriety, it might be maintained, that there is only one 

 science, at least one physical science. The various departments 



