29G 



Analysis of Graphite. 



potasbj gave an olive green precipitate; and with tincture of 

 nutgalls^ a brovvnisii red precipitate ; indicating the presence of 

 titanium. 



I liad already suspected the presence of titaniuni in graphite, 

 in consequence of a previous set of experiments. Some grains 

 of silica, which appeared to contain titanium, which I had 

 obtained in a set of very different experiments, w^ere gently 

 digested in muriatic acid. Some titanium was found, in conse- 

 quence, in the solution. The white residue, vyhieh did not 

 dissolve, was mixed with water, and set aside one night to 

 spontaneous evaporation. Next morning the liquid was found 

 transparent, but of an indigo blue colour; and immediately 

 over the white powder was a layer of flocks of an indigo blue 

 colour. 1 prosecuted this appearance, and tried if any molyb- 

 denum or tungsten could be detected ; but I could find no 

 traccs of either, nor of any other metal, except titanium. I 

 have not since remarked this appearance, in consequence of 

 similar trials. That titanium enters into combinations with 

 alkalies and earths is already known, in consequence of the 

 experiments of Vauquelin, and is fully established by my expe^ 

 riments on graphite . The titanium separates itself in this case 

 in various states and appearances. 1 must on that account give 

 a statement of my various experiments tq separate it from other 

 "bodies, and estimate its quantity. 



B. 



For the farther prosecution of these experiments on the pro-^ 

 portion of tilanium contained in graphite, 1 made choice of a 

 specimen of compact English graphite from another collection. 

 This specimen vv hen boiled in water yielded nothing remarkable 

 to tiiiit liquid, only that J.he water in which it had been boiled 

 Ldd a strong clayey taste. 



1. Two hundred grains of grapln'te, that had been thus boiled^ 

 were t)u rnt in a silver crucible, with ten times their weight of 

 saltpetre. The residue weighed 32*2 grains. 



2. This residue was boiled in nitro-muriatic acid. When the 

 liquid Vvas diluted with water, one grain of a white povv-der fell, 

 which when strongly dried became bluish. 



3. It was, together with the residue left by the nitro-muriatic 

 acid, heated to redness in a platinum crucible with an alkaline 

 ley. The mass was dissolved in water, and treated with muriatic 

 acid. By this treatment 7*2 grains of silica and 3*4 grains of 

 oxide of titanium were separated. 



4. The solution obtained in paragraph 2 was saturated witli 

 caustic ammonia. The colourless solution was evaporated, mixed 

 with a suiBcient quantity of carbonate of soda, evaporated to 

 dryness, and strongly heated, in order to get rid of the ammonia. 

 It es.hibited, before the whole of the ammonia wa3 driven off, a 



