OF ARTS AiND SCIENCES. 5 



circumstances, 5 grammes of metal would have required 50 cubic cen- 

 timetres of acid, so that the effect was obtained with only one-fiftieth 

 of tlie amount required by this theory.* 



II. Argexto-antimonious Tartrate (Silver Emetic). 



On one occasion when analyzing antimonious chloride we noticed 

 the formation of " silver emetic," and the observation led us to fear 

 that this compound might be occluded by the argentic chloride or 

 bromide, precipitated from a solution containing tartaric acid and anti- 

 mony. This suspicion, thus excited, led us to make an investigation 

 of the substance in question with the following results : — 



As stated by us in our former paper, this compound was originally 

 obtained by Wallquist by precipitating nitrate of silver with tartar- 

 emetic, and was analyzed both by him and by Dumas and Piria. 

 These chemists obtained respectively 27.31 and 28.05 per cent of 

 oxide of silver. They appear, however, to have prepared the sub- 

 stance only in an amorphous form. As stated in the pajjer just cited, 

 we first noticed the formation of crystals of the compound in a concen- 

 trated solution of antimonious chloride and tartaric acid, to which had 

 been added an excess of argentic nitrate, and from^the circumstances 

 of their formation we were led to form a somewhat erroneous infer- 

 ence in regard to their relation to water. We find that the substance 

 is far more soluble in this solvent than at first appeared. We have 

 found from further investigation that one part of silver emetic dis- 

 solves completely in one hundred parts of boiling, and in somewhat 

 less than five hundred parts of water at 15'^ C. In one determination 

 made by evajDorating, a saturated sokition, which had stood a long time 

 at a temperature of 15°, we found that one thousand parts of water 

 had dissolved 2.76 parts and in another 2.68 parts of the salt. There 



* Although in our synthesis of antimonious sulphide it was our constant study 

 from the first to prevent the oxidation of tlie product, and althougli we most 

 carefully guarded every phase of the process, yet the theory was advanced that 

 the apparent weight of the product was increased by a partial oxidation of the 

 antimonious sulphide at the temperature at which the red was converted to the 

 gray modification. In answer to this wholly gratuitous assumption, it is only 

 necessary to say : 1. That the oxidation of the dried precipitate at this stage 

 of the process is a well-marked phenomenon, with every phase of which we are 

 acquainted. 2. That the oxidation is always attended with a loss of weight. 

 S. That the products of our determinations were always examined, and have 

 been in two cases preserved, and that these do not show the least signs of 

 oxidation. 



