18 
ON SUBNITRATE OF BISMUTH. 
would bear without getting turbid, and filtered through 
doubled paper. To the filtered liquor I added for one 
pound of metal, one ounce of nitric acid, evaporated in a 
porcelain dish very slowly, and crystallized while cooling* 
After having dried the crystals, I dissolved them again with 
the aid of a little heat in two and a half parts distilled water, 
filtered the liquor and poured it, constantly stirring with a 
glass rod, in twenty-four parts boiling distilled water, 
suffered the precipitate to settle at the bottom of the vessel, 
drew off the supernatant liquor with a glass syphon, and 
again poured hot distilled water upon it, repeating that 
operation three or four times more. I then collected the 
precipitate on a filter, washed it yet several times with dis- 
tilled water, and dried it at last on paper spread over a 
slate of plaster of Paris. The precipitate was of a beautiful 
white, nearly as much in weight as the metal used, and 
quite free from arsenic, while the metal I used contained a 
considerable quantity of it, because the arseniate of bismuth 
which is formed by the solution of the metal in nitric acid, 
remained after the filtration of the solution of nitrate of 
bismuth. 
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