OP ARTS AND SCIENCES. 67 



Details of Antimony Determination. 



The antimonious chloride was first transferred to a very carefully 

 dried weighing tube, and thence to the large flask in which it was dis- 

 solved. The transfer to the weighing tube was made in a dry atmosphere, 

 and only required two or three seconds. It is evident, however, that a 

 slight absorption of moisture at this point is not important; for, even 

 if it increased the apparent weight of the assay by several milli- 

 grammes, it would only reduce to a barely perceptible extent the per- 

 centages of all the constituents leaving the relative values wholly 

 unchanged. It is only when, on boiling the chloride, after such an 

 absorption, the chlorine is driven off, that the essential change of com- 

 position results. 



Weight of tube and antimonious chloride . 20.9609 grammes. 

 „ „ after transfer to flask . . 16.3920 „ 



„ chloride analyzed 4.5689 „ 



The weight of the tube and chloride while on the balance pan 

 remained invariable for a sufficient length of time to give positive 

 assurance of the constancy of the weights. The chloride was dissolved 

 in a saturated solution of tartaric acid containing about 15 grammes of 

 the pure acid, and then diluted with carbonic acid water and precipi- 

 tated as before described. The precipitate, having been washed and 

 collected as before, was dried in an air bath, at about 110^. 



Weight of small filter 0.0434 grammes. 



„ porcelain crucible . . . . 101.2132 „ 



/ 101.2566 



crucible and precipitate . . 104.6762 



„ red sulphide of antimony . 3.4196 „ 



A portion of the dried precipitate dissolved in hydrochloric acid 

 gave no residue. The rest was then transferred to a platinum nacelle, 

 and heated, as has been described, in a current of dry carbonic dioxide 



