Mercury Perchlorates. 



By 

 Masumi Chikashige, Rigakushi. 



College of Science, Imperial University. 



Having, at the suggestion of Dr. Divers, prepared mercuric and 

 mercurous perchlorates, with the object of examining their behaviour 

 when heated, I have found their properties to be not quite as described 

 by Serallas in 1830, and by Roscoe in 1862. The earlier memoir, 

 which appeared in Ann. Chim. Phijs., [2], 45, 270, I have not seen, 

 and make my statements about its contents on the authority of the 

 larger works on Chemistry. Sir Henry Roscoe's well-known paper on 

 Perchloric acid is to be found in full in Proc. Roy. Soc, 11, 502, and 

 also in Liebigs Anncden, 121, 346. 



Most of the hydrated perchloric acid, I have used in my ex- 

 periments, was prepared from potassium chlorate and hydrofluosilieic 

 acid, following Roscoe, but some of it by the slight modification of 

 this process, more convenient at the present time, consisting in 

 replacing the above salt and acid by barium chlorate and sulphuric 

 acid. It is a fact not altogether unknown, though not mentioned by 

 Roscoe, that the hydrated acid is slightly decomposed when it is 

 distilled, and becomes contaminated with a little chlorine and hydro- 

 chloric acid in consequence. I find that heating the distilled acid for 

 a short time in the air is sufficient to free it from these impurities. 



