322 



this experiment intense ignition took place at the point of contact of 

 the substances, the potassium appearing to burn by oxygen acquired 

 from the acid, of which eight grains saturated about twenty of po- 

 tassium. 



The residuum did not effervesce in water, which merely dissolved 

 some sub-borate of potash which is formed, and leaves exposed the 

 boracic base as a spongy mass, black in some parts, and dark olive in 

 others. It appeared to be infusible by heat, but a perfect conductor 

 of electricity. When acted upon by nitric acid, or burned in oxygen, 

 it was reduced again to the state of boracic acid, probably much hea- 

 vier than the basis from which it is formed. 



When fluoric acid gas was acted on by potassium, fourteen cubic 

 inches disappeared by means of ten grains and a half of potassium, 

 and about two inches and a quarter of hydrogen gas were evolved, 

 apparently from water contained in the gas. In this experiment, a 

 brownish sublimate was sometimes raised by the heat generated, and 

 at others, a blackish matter remained mixed with a quantity of fluate 

 of potash that is formed. 



This matter appears to be fluoric acid, deprived of oxygen, and ex- 

 isting in a state analogous to that of sulphur and phosphorus ; for 

 when the sulphuric or phosphoric acids are decomposed by potassium, 

 the pure bases are not evolved, but sulphurets and sulphites, phos- 

 phorets and phosphites, are generated. 



Although the attempts to decompose the muriatic acid have not 

 hitherto been equally successful with the preceding, yet many new 

 and interesting results were obtained. When a quantity of potas- 

 sium was employed, sufficient to absorb a given quantity of this gas, 

 so much hydrogen was evolved as to prove that it contains full one 

 third its weight of water. 



Various attempts were made in consequence, to obtain the acid free 

 from water, but they only terminated in new and singular combi- 

 nations. 



By burning phosphorus in oxymuriatic acid, a very volatile com- 

 pound was obtained, consisting, apparently, of muriatic acid and 

 phosphoric acid in a dry state, and a second compound of phospho- 

 rous acid with muriatic also, free from water. Corresponding products 

 were also obtained by means of sulphur, consisting of dry sulphuric 

 and muriatic acids ; and the most remarkable circumstance attend- 

 ing these compounds, is, that they do not redden litmus paper, and 

 manifest no marks of acidity till water is added to them. 



In exposing potassium to these compounds, a violent detonation 

 takes place, and Mr. Davy has some reason to hope that the muria- 

 tic acid suffers decomposition at the time, but he has not yet been 

 able to collect the products for examination ; and the elements of this 

 acid, if separable, must remain a subject for future investigation. 



