324 On the Common Blowpipe. 



Chlorides melted with a mixture of salt of phosphorus and black 

 oxide of copper color the flame, blue or green. 



If fluorides are heated with salt of phosphorus, in the open tube, 

 hydrofluoric acid escapes, which corrodes the glass and turns Brazil 

 paper yellow. 



If phosphates are melted, by a good fire of reduction, on char- 

 coal, with boracic acid, and a small piece of iron wire is plunged 

 into the globule, it is partly oxidized at the expense of the phos- 

 phoric acid, and dissolved; while the remainder forms a phosphuret 

 of iron, which by breaking the globule, will be found as a more or 

 less brittle mass. If phosphoric acid were not present, the iron wire 

 will be found unaltered. 



If nitrates are heated in the matrass, with a drop of sulphuric 

 acid, they are decomposed with evolution of nitrous acid fumes, 

 which may be recognized by the color, and by turning to black, 

 small scales of the cyanohydrargyrate of iodide o{ potassium pre- 

 viously placed on a dry part of the tube. 



If boracic acid, or the borates are melted with Turner'' s reagent 

 (a mixture of one part of fluoride of calcium and four and a half of 

 bisulphate of potassa) a brilliant green color will be given to the 

 flame. 



Ammoniacal compounds when heated in the open tube with fixed 

 alkaline bodies, (as lime or potassa) give off ammonia which will 

 be recognized by its odor, &ic. 



Potassa gives to the brown glass of borax and oxide of nickel 

 a blue color which soda will not. 



The salts of soda color flame, a rich yellow. 



Lithia attacks platinum foil and leaves a dull yellowish trace ; and 

 minerals containing it, give at the moment of fusion (especially if 

 mixed with fluor spar) a red tint to the flame. 



Most of the salts ofstrontia impart to flame a fine red color. 



Many salts of lime give to flame a brownish red color. 



Substances containing much alumina, when moistened with ni- 

 trate of cobalt and heated, assume a beautiful blue color. 



Magnesia gives with nitrate of cobalt a pale rose color. 



When substances contain much silica they will, when fused with 

 salt of phosphorus, form a spongy mass or skeleton in the middle 

 of the globule of glass ; but if the silica is in small quantity its infu- 

 sible particles in place of forming a skeleton, remain diffused through 

 the glass and impair its transparency, giving it an opaline appear- 

 ance. 



