OF ARTS AND SCIENCES. 69 



Coming next to the chlorine determinations, we noticed, for tlie first 

 time, an effect which, under certain circumstances, may have an im- 

 portant influence on the accuracy of this well-known process, as 

 employed in the analysis of chloride of antimony. In a precipitate 

 of argentic chloride that had been deposited from an unusually con- 

 centrated solution of antimonious chloride in tartaric acid, and had 

 stood over night, our attention was called to some crystalline grains, 

 which, on examination, proved to be a compound of tartaric acid, anti- 

 mony, and silver. "We soon found that this jsroduct could be readily 

 obtained by concentrating the filtrate from the precipitate of argentic 

 chloride, and adding to it, while still warm, an excess of argentic 

 nitrate. On cooling, the new crystals form in abundance. They have 

 not yet been measured, but under the microscope they have the general 

 aspect of right rhombic plates or prisms, with hemihedral modifications, 

 — a general form which is so characteristic of the tartrates, and which 

 we ourselves have previously studied in our crystallographic determina- 

 tions of the tartrates of rabidium and cisesium.* We obtained for the 

 amount of silver in the crystals, as a mean of three analyses, 26.30 per 

 cent. The compound Ag,SbO,H,^0^=(C4H202) . HgO would require 

 26.34 %. The crystals may therefore be regarded as tartar emetic, in 

 which the potassium has been replaced by silver ; and they resemble 

 the crystals of this well-known salt in general form. Tliey are evi- 

 dently the same substance obtained by Wallquistf by precipitating 

 nitrate of silver with tartar emetic, and analyzed both by him and by 

 Dumas and Piria. These chemists obtained respectively 27.31 and 

 28.05 per cent of oxide of silver, which corresponds with the result 

 given above as closely as could be expected ; but they appear to have 

 prepared the substance only in an amorphous condition. At least, in 

 the description quoted, no mention is made of any crystalline form. 



These crystals of argento-antimouious tartrate are apparently not 

 acted upon in the least by cold water, and only slightly by boiling 

 water ; and finding this very insoluble material mixed with the precipi- 

 tated chloride of silver, under the conditions stated, we were led to fear 

 that it might be occluded to some extent by this precipitate, even when 

 formed in much more dilute solutions of antimony and tartaric acid. 

 The phenomenon was very similar to that we had already studied in 

 the occlusion of the oxichloride by the sulphide of antimony ; and there 

 was reason to fear that, as in the previous case, an occlusion of this 



* Am. Jour, of Science and Arts. (2), xxxvii. 70. 

 t Gmelin Handbook, Cavendish Edition, x. 326. 



