on thejiuoric Compounds. 97 



ga«, and, in attempting to collect them by the filter, I failed to 

 procure sufficient for examination, for they were principally 

 converted into silica. 



I heated the substance procured in another experiment of 

 this kind with hydrate of potassa; in this case there was a copious 

 effervescence, and silica appeared to be reproduced and dis- 

 solved by the alkali. 



I heated a jjortion of a similar result in strong lixivium of 

 potassa; the snlution gained a tint of olive, but there was 

 sr;:ircelv anv effervescence : from this it seems probable, that 

 the inflanunablc basis of silica, like boron, is soluble in alkaline 

 solutions witlioiit decomposing them. 



Indeed tliis body, in its 'general ciiaracters, appears very ana- 

 logous to boron. It appears to be neither volatile nor fusible j 

 its oxide exerts, like boracic acid, a neutralizing power on the 

 alkalies, though of a feebler kind, and forms, like boracic acid, 

 vitreous bodies with the alkaline earths ; and, like boron, the 

 siliceous basis in combination with fluorine constitutes a power- 

 ful acid. 



In my first views of the nature of the boracic and siliceous 

 bases, I tiiought it ))robable that they would both appear as 

 metals, if they could l)e entirely freed from oxygen ; but it now 

 seems more prol)ahle, that they form a class by themselves, 

 offering a kind of link in the cliain of natural bodies, when ar - 

 ranged according to their analogies, between charcoal, and sul- 

 phur and phosj)horus. 



It seems worthy of an experimental inquiry, whether the si- 

 liceous basis mav not be obtained pure by heating the result 

 j)r(>eured from silica by potassium with pure sulphuric acid, 

 which might possibly detach the potassa to form acid sulphate 

 of .potassa, without being decomposed by the inflammable basis. 



I have made maiiv i.ew experiments with the hope of decom- 

 posing chlorine, but they have been all miavailing; nor have 

 I been able to gain the slightest evidence of the existence of 

 that oxygen which many persons still assert to be one of its ele- 

 ments. 



I kep/t sulphuret of lead for some time in fusion in chlorine; 

 the results were sulphurane (Dr. Thomson's liquor) and plum- 

 bane (nuiriate of lead) ; not an atom of sulphate of lead was 

 formed in the experiment, though, if any oxygen had been pre- 

 sent, this suljbtance might have been expected to have been 

 jjroduccd. 



I hciitetl plumbane (nmrinte of lead) in sulpluirous acid gas, 

 and likewise in carbonic acid gas, but no change was produced : 

 now, if oxygen had existed eilher in chlorine, or in its combina- 

 tion with lead, tliere is every reason to believe, that the attruc- 



Vol.44, No.l96. ^//nr?^/ iSH. (i tions 



