OP ARTS AND SCIENCES. 



11 



method of precipitating metallic sulphides, desciibed in the previous 

 volume of this series,'* and found that by its means, and also by boil- 

 ing the liquid, as suggested by Mr. S. P. Sharpies,! we could precipi- 

 tate sulphide of antimony in a condition apparently peculiarly well 

 adapted for accurate determination, we conceived the idea of reversing 

 Schneider's method, and verifying his result by a synthesis of the same 

 material which he analyzed. The event, however, proved that we had 

 undertaken a work of far more difficulty than we anticipated. We 

 have met unforeseen obstacles at almost every step of our investiga- 

 tion, and have had constant occasion to indorse, with Kessler, the 

 opinion of Berzelius quoted above. 



In the preparation of pure metallic antimony, we were greatly guided 

 by the experience of Mr. Dexter; J and our several products must 

 have been very similar to his, as the following determinations of 

 the specific gravities of the different buttons show. The observed 

 values were reduced to 4° C, on the assumption that the coefficient 

 of cubic expansion for antimony between 0° and 100° C. is for each 

 degree 0.000033, as observed by Kopp. The letters here given will 

 be used throughout the table to designate the various specimens. As 

 might be supposed, the specimens were prepared at diffisrent times and 

 at different stages of the investigation, but the results are united here 

 for the convenience of comparison and of reference. 



Specific Gravities of Buttons of Pure Metallic Antimony. 



Observations of J. P. C, Jr. 



A 6.7025 



B 6.7036 



C 6.61)57 



D 6.7070 



E 6.7022 



F 6.7023 



Mean 6.7022 



Observations of W. Dexter. 



b 6.7087 



c 6.7026 



c ..'.... 6.6987 



d 6.7102 



e 6.7047 



6 6.7052 



Mean 6.7050 



* On a New Mode of Manipulating Hydric Sulphide, vol. xii. of these 

 Proceedings, p. 113. 



+ American Journal of Science and Arts, Second Series, vol. 1. p. 248. 

 X Poggendorff's Annalen, Band 100, Seite 564 [loc. cit.). 



