360 Researches on the muriatic Acid. 



assume the existence of any peculiar acid in it, or of a 

 considerable portion of combined water; and it is per- 

 haps more conformable to the analogy of chemistry, to 

 suppose the large quantity of oxygen combined with the 

 potassium, which we know has an intense affinity for oxy- 

 gen, and which, from some experiments, T am inclined to 

 believe, is capable of combining directly with more oxygen 

 than exists in potash, than with the oxymuriatic acid, which, 

 as far as is known, has" no affinity for that substance. 



It is generally supposed that a mixture of oxymuriatic 

 acid and hyperoxymuriatic acid is disengaged when hyper- 

 oxymuriate of potash is decomposed by common muriatic 

 acid* ; but I am satisfied from several trials, that the gas 

 procured in this way, when not mixed with oxygen, unites 

 to the same quantity of hydrogenf , as common oxymuriatic 

 acid gas from manganese; and I find, by a careful exami- 

 nation, that the gas disengaged during the solution of pla- 

 tina, in a mixture of nitric and muriatic acids, which has 

 been regarded as hyperoxymuriatic acid, but which 1 stated 

 some years ago to possess the properties of oxymuriatic acid 

 gas X, is actually that body, owing its peculiar colour to a 

 small quantity of nitromuriatic vapour suspended in it, and 

 from which it is easily freed by washing. 



Few substances, perhaps, have less claim to be considered 

 as acid, than oxymuriatic acid. As yet we have no right 

 to say that it has been decompounded; and as its tendency 

 of combination is with pure inflammable matters, it may 

 possibly belong to the same class of bodies as oxygen. 



May it not in fact be a. peculiar acidifying and dissolving 

 principle, forming compounds with combustible bodies, 

 analogous to acids containing oxygen or oxides, in their 



* If hyperoxymuriate of potash be decomposed by nitric or sulphuric acid, 

 it affords oxymuriatic acid and oxygen. If it be acted upon by muri at it- 

 acid, it affords a large quantity of oxymuriatic acid gas only. In this lust 

 case, the phenomenon seems merely to depend upon the decomposition of 

 the muriatic ac d gas, by the oxygen, loosely combined in the salt. 



f This likewise appears from Mr. Cruikshank's experiments. See Nichol- 

 son's Journal, vol v. 4to,p. 20G\ 



\ The platina, I find by several experiments made with great care, has no, 

 share in producing the evolution of this gas. It is formed during the pro- 

 duction of aqua regia. The hydrogen of the muriatic acid attracts oxvgcn 

 from the nitric acid. Oxymuriatic acid gas is set free, and nitrous gas re- 

 mains in the solution, and gives it a deep red colour. Nilrous acid and mu- 

 riatic acid produce no oxymuriatic acid gas, Pl.tina, during its solution in 

 perfectly formed aqua regia, gives only nitrous gas aud nitrous vapour; and 

 I find, that rather more oxymuriatic acid gas is produced, bv heating toge- 

 ther equal quantities of nitric acid of I - 45, and muriatic acid of 1*18, when 

 they aie not in contact with platina, than when exposed to that metal. The 

 oxymuriatic acid gas produced from muriatic acid by nitric acid, I find 

 combines with about an equal volume of hydrogen by detonation. 



p,roperlies 



