29S 



Analysis of Graphite, 



5. The alkaline ley from which the brov/nish black powder of 

 paragraph 3 bad separated, was supersaturated with muriatic 

 acid, and evaporated. It became m consequence gelatinous. 

 The silica being separated, and heated to redness, weighed 7 

 grains. 



6. The diluted acid solution of paragraph 3 was precipitated 

 by means of caustic ammonia. The precipitate, while still 

 moist, was boiled with caustic soda, wdiich took up 3-6 grains of 

 alumina. 



7. The ferruginous precipitate wiiich had been boiled in th& 

 alkaline ley and edulcorated, was dried ; and being mixed with 

 the oxide of iron obtained m paragraph 8, was rubbed into a 

 paste with oil, and exposed to a red iicat. There remained ll'G 

 grains of black oxide of iron, which was completely attracted by 

 the magnet. 



8. The ammoniacal ley, from wliicli the iron had been pre- 

 cipitated in paragraph 5, was entirely colourless. It was concen- 

 trated by evaporation ; but still acquired no colour. It was mixed 

 with a sufficient quantity of potash, evaporated to dryness, and 

 exposed to a heat sufficient to drive olf the whole of the ammo- 

 nia. The dry salt had a greenish yellow colour. When it was 

 dissolved in water a blackish brown powder separated, which 

 weighed 4*6* grains, and which being digested with ammonia 

 neither assumed a blue colour, nor did prussiate of potash 

 indicate that it contained any copper. Farther experiments 

 convinced me that this residue contained titanium. It was se- 

 parated in the following manner : — 



The powder was heated to redness with saltpetre in a platinum 

 crucible. The saline residue being dissolved in waiter, no per- 

 ceptil)le portion of the powder was taken up. Its colour was 

 now rather reddish than brown. It v/as gently digested with 

 very dilute muriatic acid, which acquired a yellow colour, and 

 a blackish grey powder still remained undissolved. The muriatic 

 solution being treated with caustic ammonia, oxide of iron fell, 

 which was mixed v/ith that of paragraph 7- The ammoniacal 

 solution, which was colourless, being neutralized, and mixed 

 with prussiate of potash^ assumed a light reddish colour, with a 

 distinct opalescence. This colour might perhaps originate from 

 a trace of copper, so small that its quantity could not be esti- 

 mated. Whence the shade of white mixed with the red pro- 

 ceeded it is impossible to say. It might perhaps be owing to the 

 presence of a small portion of alumina. 



The blackish grey residue which the muriatic acid had not 

 dissolved weighed 2*5 grains, and was completely dissolved by 

 Dstro-muriatic acid. The solution had a greenish yellow colour. 

 Tincture of nutgalls threw down from it a brownish red precipi- 

 tate; and prussiate of potasli, a precipitate which had a dirty 

 greenish colour. The ieek-green colour could be distinguished^ 



