on the Nature of certain Bodies. 4 69 
I heated intensely, in an iron tube, silex in a very minute 
state of division, and muriate of soda that had been fused ; 
but there was not the smallest quantity of gas evolved. In 
this case, the silex had been ignited to whiteness before it was 
used ; but when silex in its common state was employed, or 
when aqueous vapour was passed over a mixture of dry silex 
and dry salt in a porcelain tube, muriatic acid gas was deve- 
loped with great rapidity. 
I have stated, page 79, that a sublimate is formed by the 
combustion of the olive-coloured oxide of boracium in oxy- 
muriatic acid. On the idea that this might be boracic acid, and 
that dry muriatic acid might be separated in the process, I 
examined the circumstances of the experiment ; but I found 
the sublimate to be a compound of boracic and muriatic 
acid, similar to the compound of muriatic and phosphoric 
acid. 
I heated freshly sublimed muriate of ammonia with potas- 
sium ; when the quantities were equal, as much hydrogene 
gas was developed as is generated by the action of water on 
potassium ; much ammonia was evolved, and muriate of pot- 
ash formed ; when the potassium was to the muriate as 4 to 
1, less hydrogen appeared, and a triple compound of muriatic 
acid, ammonia, and potassium, or its protoxide was formed, 
which was of a dark gray colour, and gave ammonia and 
muriate of potash by the action of water. There was not the 
slightest indications of the decomposition of the acid in the 
experiment. The process, in which this decomposition may 
be most reasonably conceived to take place, is in the combus- 
tion of potassium in the phosphuretted muriatic acid, deprived 
mdcccix. 3 P 
