15 



together. When poured rapidly into a large quantity of cold water, 

 a portion of it sinks to the bottom, and only gradually dissolves as 

 a mixture of hydrochloric and sulphuric acids. When a small 

 quantity of water is added to the compound, the same decomposition 

 takes place with explosive violence. The acid dissolves chloride of 

 sodium on the application of a gentle heat with evolution of hydro- 



Na 



chloric acid, giving rise to a compound of the formula SO 2 . When 



Cl, 



poured upon pieces of melted nitre at the atmospheric temperature, 

 an effervescence takes place with evolution of a colourless vapour 

 which possesses in a striking degree the odour of aqua regia. This 

 vapour may be dissolved in various liquids, and when decomposed 

 by water, yields nitric and hydrochloric acids. It is doubtless 

 chloro-nitric acid, NO 2 C1. In like manner the chlorides of other 

 inorganic acid radicals may be obtained, as from chlorates, perchlo- 

 rates, sulphites, &c., but of these and other reactions I beg leave to 

 defer any further account until the experiments now in hand are 

 more advanced. 



From the general resemblance of properties and identity of boiling- 

 point of the chloro-hydrate with a compound discovered by Rose, 

 and described by that eminent chemist as possessing empirically the 

 composition S 2 O 6 C1 2 , I was led to suspect that the two might in 

 reality be identical, which of course would require the addition of 

 the elements of water to Rose's formula, and several experiments I 

 have performed afford strong confirmation of that identity. The 

 same compound is obtained by the action of dry hydrochloric acid 

 on anhydrous sulphuric acid ; and finally, I may mention that 

 Mr. Railton obtained a small quantity of the same substance some 

 weeks ago in my laboratory by the action of platinum-black at a 

 high temperature on an imperfectly dried mixture of chlorine and 

 sulphurous acid. 



As regards the successive transformations effected in the penta- 

 chloride, I have observed the .formation of Wurtz's oxychloride (the 

 tribasic chloro-phosphoric acid (PO C1 3 )), and also of a compound 

 boiling above 145, probably PO 2 Cl. Hydrated phosphoric acid is 

 always found unless the amount of pentachloride added is very 

 great. 



