MERCURIC SALTS CHANGE INTO EACH OTHER. ^35 



quantities were : .1823 gram in solution and .16 gram sublimed. 

 The effect of the potassium chloride upon the dissociation had therefore 

 been marked. 



In all these experiments minute globules of mercury were visibly 

 mixed with the mercurous chloride, thus accounting for the deficiency 

 of sublimed mercury. The absence of oxygen in the carbon dioxide 

 experiments showed that little if any oxidation could have occurred in 

 the air experiments. Its absence may be assumed on the grounds of 

 its absence in the nitrate experiments. In any case, dissociation of 

 mercurous chloride in water at 100° is fully established by these 

 experiments. 



Of the dissociation of mercurous chloride by light I can say 

 nothing, beyond referring to the fact that mercurous chloride turns 

 dark brown in strong light. 



Mercurous chloride not changed by boiling water except in sloivly dis- 

 appearing as mercury and mercuric chloride. — If shaded from daylight 

 and contained in a porcelain or hard glass vessel, mercurous chloride 

 may be boiled with distilled water, so long as any of it remains, 

 without suffering any change in appearance or composition. 



(Literature and criticism). — Very many statements of the results of 

 experiments have been made, which, as admitted in Gmelin's summary 

 of them, are often contradictory. Most of the work is so old that the 

 original accounts of it could not be consulted ; Gmelin-Watts' Hand- 

 book is the authority relied upon. Simon found mercurous chloride 

 boiled with water in an open vessel to disappear very slowly, and in 

 such a way that the still undissolved matter consists of unaltered 

 mercurous chloride. Guibourt also stated that the residual mercurous 

 chloride is unchanged. Simon nnd Guibourt's observations are there- 

 fore in agreement with mine. But the statements of Righini, Pagen- 

 stecher, Donovan, Grüner, Vogel, and Peschiar are to the effect that 



