Action of Hydrochloric- Acid Gas on Iceland Spar. 117 



inch. After the elevator has been started the supply of 

 water may be reduced till just sufficient to raise the mercury. 

 The quantity of water then used to keep it going is very 

 small. I may add, in conclusion, that the air-compressor is 

 also used in the laboratory for supplying a blowpipe and small 

 gas-furnace, and other lecture-apparatus in which compressed 

 air is required. 



Oxford, June 11, 1892. 



XII. The Action of Dried Hydrochloric- Acid Gas on Iceland 

 Spar. By R. E. Hughes, B.Sc, Scholar of Jesus College, 

 Oxford, and F. R. L. Wilson, B.A., Scholar of Keble 

 College, Oxford*. 



KOHLRAUSCH asserts that all pure substances are 

 electrolytes, and if the assumption of Ostwald be true 

 that chemical reactions take place only between the electro- 

 lytic ions, it follows that no reactions are possible between 

 pure substances, and only become possible in the presence 

 of some body which is capable of producing the electrolytic 

 dissociation. 



Inasmuch as the majority of chemical reactions take place 

 in the presence of water or some other solvent, and since the 

 experiments of Dixon on the explosion of mixtures of dried 

 gases, Wanklyn on the action of dry chlorine on metals, 

 Baker on the combustion of dry substances, and Veley on the 

 action of dry sulphuretted hydrogen on oxide of calcium, 

 prove that the presence of water is an essential condition for 

 these reactions to take place, it seemed an interesting 

 question to determine whether dried hydrochloric-acid gas is 

 capable of displacing carbon dioxide from carbonates. 



Therefore, at the suggestion of Mr. V. H. Veley, M.A., 

 we have undertaken an investigation with this object in view. 



It must be mentioned that the action of liquefied hydro- 

 chloric acid on various carbonates has been investigated by 

 Gore, as a result of which he found that, with the exception of 

 calcium carbonate, all the carbonates investigated showed a 

 more or less complete conversion into the chlorides. 



Wiedemann, in the British Association Report for 1887, 

 states that " Dr. Gore has shown that if you put anhydrous 

 liquefied hydrochloric acid upon carbonate of lime, the carbonic 

 acid is chased away and calcium chloride is formed " ; but 

 what evidence there is for such a statement we are at a loss 

 to determine. 



* Communicated hv Professor Odlin<>-, F.R.S. 



