on the Nature of certain Bodies. 183 



The alkalies and the earthy compounds, and the oxides, 

 as dry as we can obtain them, thouoh non-condnctors when 

 solid, are, on the contrary, all conductors when rendered 

 fluid l>v heat. 



When muriatic acid, existing in combination with phos- 

 phorus or phosph(^ric acid, i< rendered tiaseous by the ac- 

 tion of water, the quantity of this fluid that disappears, at 

 least equak from one- third to tK\o-fiii.hs of the weight of 

 the acid gas produced ; a circumstance that agrees with the 

 indications given by the action of potassium. 



I attempted to procure a compound of dry muriatic and 

 carbonic acids, hoping that it might be gaseous, and that 

 the two acids might be decomposable at the same time by 

 potassium. The process that I employed was by passing 

 corrosive sublimate in vapour through charcoal ignited to 

 whiteness ; but I obtained a very small quantity of gas, 

 which seemed to be a mixture of common muriatic acid gas 

 and carbonic acid gas; a very minute portion of running 

 luercury only was obtained, by a long continuation of the 

 process ; and the slight decomposition that did take place, 

 I am inclined to attribute to the production of water, by 

 the action of the hydrogen of the charcoal upon the oxygen 

 of the oxide of mercury *. 



In mixing muriatic acid gas with carbonic acid, or oxy- 

 gen, or hydrogen, the gases being in their common stales, 

 as to moisture, there was always a cloudiness produced ;. 

 doubtless owing to the attraction of their water to form 

 liquid muriatic acid. 



On fluoric acid gas no such effect was occasioned. This 

 fact, at first view, might be supposed to show, that the 

 hydrogen evolved bv the action of potassium upon fluorie 

 acid gas, is owing to water in actual combination with it, 

 Hke that in muria-ic acid gas, and which may be essential 

 to its elastic state ; but it is more probable, from the sniall- 

 ncss of the quantity, and from the difference of the quan- 

 tity in different cases, that the moisture is merely in that 

 slate of diff'usion or solution in which it exists in gases in 

 general, though from the disposition of water to be depo- 

 sited in this acid gas in the form of an acid solution, 

 it must be either less in quantity, or in a less free state, so 



• Thefe facts and the other f.icts of the same kind, explain the difliculty 

 of the decomposition of the met:iHii muriale^ in common processes of metal- 

 lurgy. Tlicy likewiiie explain other plixnomena in the ajjencies of muriatic 

 saltii. lu all cases when a muriatic salt i> decomposed ijy an acid, and mu- 

 riatic acid gas set free, there appears to be a doulile admity, ihat of the acid 

 for the l»as!6, and of the muriatic arid for water ; pure muriiitic acid does 

 not sfcm capable of being displaced by any other acid. 



ai 



