ON THK ALKALINE METALLOIDS. ^4^ 



on it ; aiul which, as it appeared not difficult to execute 

 with nccuraoy, I preferred ;~'\s to ascertain the nature of the 

 product of the oxi^eiiation of potassium. It was ascertained 

 by Mr. Davy, that, when potassium combines with oxigen, 

 it forms solid, and apparently unusually dry potash. Now if 

 potassium is simply the bat.e of the allcali, forming it when 

 united with oxij^en, the potash formed in this way must be 

 the pure alkali; there is no source whence any water can be 

 communicated to it, and of course it cannot contain that 

 portion of water, which is essential to the potash prepared 

 by the common process. But if it be found to contain 

 water, it may be inferred, that hidrogen had existed in the 

 composition of potassium, which, combining with oxigen 

 during the combustion, formed this water. 



Mr. Davy had perceived the importance of the inquiry Mr. Davy's 

 with regard to the presence of water in potash, and endea- <^^'c"^3tion of 



,1 • , . • oil !> , ^htf dryness of 



voured to determine the relation ot the dryness or the pot- potash formed 



ash formed from potassium to that existing in some of its *[®^ potas- 



siuni 

 saline combinations supposed to be free from water. Ber- * 



thollet liad inferf^ed, that potash which had been in fusion 



parts with 13*89 ^f water when it enters into combination 



vith muriatic acid. By converting potassium into muriate 



of potash in muriatic acid gas, Mr. Davy obtained results, 



whence he inferred, that the alkali, which Berthollet had 



taken as a standard, contains Q per cent more water than tliat 



existing in the petash formed by the combustion of potassium 



in muriatic acid gas, so that the fused potash of Berthollet 



contains consequently near 23 per cent of water; and he 



adds, that, from his own observations, potash kept for some 



time in a red heat contains l6 or 17 per cent of water, taking 



the potash formed by the combustion of potassium as the 



dry standard. 



These conclusions however become uncertain in conse- liable to uncer- ' 

 quence of the different theory, which Mr. Davy has pro- ^^^"^^®^* 

 posed on the action of muriatic acid gas on potassium ; they 

 are liable too to the uncertainties, which arise from the diffi- 

 culty of estimating the quantity of water in muriatic acid, 

 and the subject must be investigated under another form. 



The following appeared to me to be the simplest mode of Cgirparison of 

 experiment, that in which tlie conclusion is most direct, *^^® °®"^''*" 



2 ' and 



