S80 <^N THE DEPOMrOSITTON OF tHE EARTHS. 



Treated as in- Xliis result having taken place, the same plan of operation 



flammables sa- , j • . . ^ ^ i • t • , 



turated with ^*^ "°* piirsucd With respect to alumrae, -which resembles a 



cjtigen. saline compound less than silex ; and the method which I now 



adopted of acfing upon these bodies was on the supposition 

 of their being inflammable substances so highly saturated 

 yviih oxigen as to possess little or no positive electricity. 



AluTRine and silex have both a strong affinity for potash 

 and soda; now supposing them to be oxides, it was reason- 

 able to conclude, that the oxigen, both in the alkalis and 

 the earths, must be passive as to this power, which must 

 consequently be referred to their bases, and on this notion 

 it was possible, (hat it might be made to assist their decom- 

 position by electricity. 

 Silex 1 p. pot- After this reasoning, I fused a mixture of one part of si- 

 fiision'in a ph" ^^^^ ^"^ ^'^ ^^ potash in a platina crucible, and preserved 

 tina crucible the mixlure fluid, and in ignition, over a fire of charcoal ; 

 jind eiectrifted. ^^^ crucible was rendered positive from the battery of five 

 hundred, and a rod of platina, rendered negative, was 

 brought into contact with the alkaline menstruum. At the 

 moment of contact there was a most intense light ; when 

 the rod was plunged into the liquid an effervescence took 

 place, and globules, which burnt witli a brilliant flame, 

 rose to the surface, and swam upon it in a state of com- 

 bustion. In a few minutes, when the mixture was coo!, 

 the platina bar was removed: after as much as possible of 

 the alkali and silex had been detached from it by a knife, 

 there remained brilliant metallic scales round it, which in- 

 stantly became covered with a white crust in the air, and 

 some of which inflamed spontaneously. The platina appeared 

 much corroded, and of a darker tint than belongs to the pure 

 metal. When it was plunged into water it strongly effer- 

 Tesced: the fluid that came from it was alkaline; when a 

 few drops of muriatic acid were added to the solution, a 

 white cloudiness occurred, which various trials demonstrated 

 to depend upon the presence of silex. 



hence the experirr.ent on tiie r>cti6n of the bOracic acid and po^ 

 tassium, page 375, inaj.|[>osb-Jb!y be explained without assuming 

 its decomposiuoa. 



A similar 



