4 Analysis of the residuum of fired gunpoivder. [J ax* 



clue to consist of a small quantity of charcoal, and carbonate 

 of lime and other earths, being small impurities from the salt- 

 petre and sulphur. 



17. ' — Having thus ascertained the general nature of the 

 substance experimented on, we may proceed to the 1 



EXAMINATION OF QUANTITY. 



18. — Fifty grains of the alkaline matter were heated over 

 a spirit lamp till they no longer lost weight, and were weighed 

 in a porcelain capsule while hot. 



19. — Note. — All the weighings hereafter mentioned were 

 weighed hot in the same manner. A small porcelain capsule 

 will weigh 5, or 6 tenths of a grain heavier when cold, than 

 it does when hot. 



20. — The 50 grains of residuum were dissolved in cold 

 distilled water ; filtered, and washed, till reddened litmus 

 ceased to be affected. 



21. — The residue retained by the filter (16) weighed 0.90 

 of a grain, it was submitted to a red heat ; and consisted of 



Charcoal, grains 0.25 



Earthy matter ,, 0.65 



22. — The solution was precipitated with nitrate of ba- 

 ryta, (8) the precipitate weighed grains 43.60. 



23. This precipitate was treated with nitric acid (8) ; it 

 effervesced, and when again collected and dried at a heat 

 near redness weighed gr. 23.10. 



.24. — There resulted therefore— 



Sulphate of baryta. .... .grains 23.10 



Carbonate of do „ 20.50 



Grains 43.60 



25. — The solution remaining after this step of the experi- 

 ment, exhibited traces of free alkali (15) it was neutralized 

 by a drop of nitric acid. 



26. — Nitrate of silver was then added until there ceas- 

 ed to be a precipitation. The result was sulphuret of silv- 

 er grains 15.40. 



27. — The solution now contained nothing but the base, 

 potash, in combination with nitric acid. The same indica- 



