Properties of Liquefied Hydrochloric Acid Gas. 549 



solved 2, viz. pentachloride of phosphorus and protochloride of tin ; 

 and of 7 organic bodies it dissolved 2. 



The results show also that liquid hydrochloric acid in the anhy- 

 drous state manifests much less chemical action upon solid bodies than 

 the same acid when mixed with water as under ordinary circum- 

 stances ; for instance, the difference of its action upon magnesium, 

 zinc, cadmium, and even aluminium, under the two conditions, is 

 very conspicuous. This may arise in a great measure from its feeble 

 solvent capacity — insoluble films forming upon the surface of the 

 bodies immersed in it preventing its continued contact and further 

 action. This want of contact could hardly have been the case in 

 the remarkable instance of caustic lime : here was a powerful and 

 true acid (i. e. a hydrogen acid) and a powerful base; each in a nearly 

 pure state ; both possessing under ordinary circumstances a very 

 powerful chemical affinity for each other ; the one a liquid, and the 

 other a porous solid; brought into intimate contact by an enormous 

 pressure forcing the liquid into the porous solid ; the solid base 

 being very small in bulk, and the liquid acid largely in excess, 

 probably fifty times the quantity necessary for its saturation ; and 

 the action extended over a far greater period of time than would in 

 the presence of water been at all necessary : nevertheless no percep- 

 tible chemical action occurred ; the two remained totally uncombined. 



It must not be overlooked that the results are partly due to an- 

 hydrous hydrochloric acid in the liquid state, and partly to the 

 same acid in the gaseous state, under great pressure, the one class 

 of effects not being eliminated from the other in the present expe- 

 riments ; it is probable that if the substances could have been sub- 

 mitted to the action of the liquid acid alone, the chemical effects 

 would have been much smaller even than they were. For instance, 

 the action upon potassium, sodium, and tin appeared to be due to 

 the influence of the acid in the gaseous state, as no gas was percep- 

 tibly evolved by these metals in the liquid acid. In the cases of 

 potassium and sodium (the latter in particular) it is perhaps pos- 

 sible, though highly improbable, that the whole of the metal had 

 been corroded before the liquid acid touched it ; but with tin this was 

 certainly not the case, some metallic tin being left uncorroded at 

 the end of the experiment. 



Oxides in general, with the exception of lime and certain others 

 which do not readily combine with aqueous hydrochloric acid, were 

 slowly converted in a greater or less degree into chlorides. Carbon- 

 ates also, except that of lime, were in general converted in a greater 

 or less degree into chlorides. 



Such carbonates as were decomposed evolved no visible bubbles of 

 gas in the liquid acid : this may be explained on the supposition that 

 they were previously completely decomposed by the gaseous acid 

 during the process of generation (this, however, was not the case with 

 carbonate of soda), or that the liberated carbonic acid was in the 

 liquid state and was dissolved by the liquid hydrochloric acid. In 

 my former paper it was shown that liquid carbonic and hydrochloric 



