Mr. Taylor on the Solubility of Arsenious Acid. 483 



" One thousand parts of temperate water dissolve, of their weight 

 of arsenious acid, according to — 



Despretz, La Grange, Bucholz, Guibourt, Hahnemann, 



STJ 2(7 3TI WU 30 



Spielmann, Ure, Klaproth, Fischer. 



" The results of some of these experimentalists were probably ob- 

 tained by boiling the water on arsenious acid, allowing the solution 

 to cool, and then estimating the quantity dissolved ; while those of 

 others were probably deduced from the actual digestion of the poison 

 in cold water. It is perhaps in this way that we may reconcile the 

 enormous difference between the statements of Despretz and Fischer j 

 the former making arsenic sixty times more soluble than the latter. 



" One thousand parts of boiling water dissolve, of their weight of 

 arsenious acid, according to 



Guibourt, Bucholz, Klaproth, Ure, La Grange, De la Metherie, 



k TT tV • A iV fa 



Vogel, Beaume, Navier, Nasse, 



"sV "fa SO 200 



* The differences in this table may perhaps be explained, by sup- 

 posing that a heat of 212° may have been applied for different periods 

 of time j as also that specimens of arsenious acid, probably varying 

 considerably in their degree of purity, may have been employed. 



" It was the discovery of these very different results, respecting the 

 solubility of arsenic, by men of well-known authority as chemists, that 

 first induced me to endeavour to ascertain which statement was borne 

 out by experiment. 



" In relation to specific gravity, I found that of a mass of arsenious 

 acid which had been kept four years, and was perfectly opaque — pre- 

 senting, when fractured, a slightly crystalline structure — to be 3*529. 

 Having procured a recently-prepared specimen, perfectly transparent, 

 but of a slightly-yellowish tinge, I tried its specific gravity, and found 

 it to be 3798. 



" Arsenious acid, it may be remarked, is soluble in water, oils, and 

 alcohol. Water is its most common solvent : and it is, therefore, of 

 its solubility in this menstruum that I shall first proceed to speak. 

 The water employed in the experiments mentioned below, was the 

 common water of the Hospital, which is the Thames water, filtered. 

 It contains, comparatively, little foreign matter. A given measure of 

 this water weighed 7527 gr. ; while the same measure of recently-dis- 

 tilled water weighed 752 gr. Its specific gravity will therefore be 

 1 -00093. Distilled water was not employed in these experiments, 

 since I had a medico-legal object in view : in no case of criminal 

 poisoning is it likely that distilled water will be used by the suicide or 

 murderer. In the course of many experiments, however, there did 

 not appear to me to be the least appreciable difference in the solvent 

 power of water over arsenious acid, whether distilled, or common river- 

 water filtered, was employed. 



" Exp. 1 . Twenty grains of opaque arsenious acid, reduced to a fine 

 powder, were placed in a clean glass vessel, and eight fluid ounces of 



3 Q2 



