OP ARTS AND SCIENCES. 3 



reduced the oxidized solution by boiling the liquid over antimony 

 buUets, and determined the loss in their weight. This method is fully 

 described in our original paper, and is based not only on the reducing 

 power of the metal, but also on the fact repeatedly observed, that, after 

 the reduction was complete, the smallest excess of the finely pulver- 

 ized metal would not dissolve, even after prolonged boiling, and in 

 the presence of a large excess of acid, if only the solution was pro- 

 tected from oxidation. 



We began our experiments by dissolving 1.0036 grammes of pure anti- 

 mony (a portion of the same used in our experiments on the synthesis of 

 antimonious sulphide) in about 30 cubic centimetres of pure hydrochloric 

 acid (sp. gr. = 1.175) adding 3 cubic centimetres of very dilute nitric 

 acid (containing only about 5.4 per cent of HNOo). After the solu- 

 tion was completed we added bullets made of pure antimony (the 

 same that had been used in our previous experiments), and boiled the 

 solution in an atmosphere of cai-bonic dioxide, using the same appa- 

 ratus which we described in our previous paper (loc. cit.). After the 

 reduction was ended, the solution was transferred to a flat-bottomed 

 flask through a platinum tunnel, on which the bullets were retained ; 

 and, after washing into the flask the last traces of the solution, with 

 as small an amount of hydrochloric acid as possible, the tunnel was 

 removed, the bullets washed with water, and again weighed as at first 

 on the platinum tunnel. In reducing the original solution, 0.4100 of 

 a gramme of antimony were dissolved from the bullets. The solution 

 now containing 1.413G grammes of antimony was next exposed to the 

 air for different successive periods of time in a room having a varying 

 temperature of from 15° to 30°, sometimes in the shade, and at other 

 times on a window seat, where the sun's direct rays fell on the flask 

 during several hours of each clear day. 



We give in the following table the weight of antimony dissolved 

 from the bullets after each successive exposure to the air, the amounts 

 in each case being determined with all the precautions described above, 

 and still more at length in our former paper : — 



Weight of Sb originally dissolved .... 1.4136 



1. Dissolved from balls after 3 days' exposure, 0.0150 



2. " after 5 days 0.0295 



3. « " 10 '' May 17 to May 27 . 0.0600 



4. " " 23 " May 27 to June 19 . 0.1340 



5. « " 37 " June 19 to July 26 . 0.2960 



6. « " 120 " July 26 to Dec. 24 . 0.4481 0.9826 



