OF ARTS AND SCIENXES. 129 



Synthesis of Sulphide of Axtimo.vy. 



Analysis of Antimoniods Chloride. 



Weight in Grammes "Weight of AgCl Per cent 



of Sb CI3 taken. obtained. of Chloiine 



20300 3.8282 4G.652 



1.3686 2.5813 46.659 



1.8638 3.5146 46.651 



Analysis of Antimonious Bromide. 



These analyses exhibit a fair sample of the results which can easily 

 be obtained with this method. In order to assure ourselves that the 

 weiglit of the small paper disks remained constant, we have repeat- 

 edly dissolved off the small amount of adhering precijiitate, and after 

 washing and drying reweiglied the disks at the completion of the 

 analysis. Even with the larger di?ks there was in no case any mate- 

 rial change in the weight, and in most aises no alteration whatever 

 could be detected with a balance turning readily with -j^ of a milli- 

 gramme. 



The method of collecting precipitates here described, which, as we 

 have shown, is so useful where considerable quantities are to be esti- 

 mated, is equally applicable to very small amounts. When the quan- 

 tity of the precipitate does not exceed a few milligrammes, the whole 

 becomes fiistened by the suction to the surface of the paper. There is 

 then, of course, no need of a crucible in the process. The filter, hav- 

 ing been dried in a watch glass, is weighed by itself, and a result of very 

 great accuracy is reached with great i-apidity. AVe have in this way fre- 

 quently estimated minute quantities of baric sulphate and argentic chlo- 

 ride, whose weight proved to be only a fraction of a milligramme. 



VOL. XII. (n. S. IV.) 9 



