148 Seyherfs Analysis of Pyroxene. 



cipitate was formed, which entirely redissolved in the ex- 

 cess of Alcali ; therefore no Alumina was dissolved by the 

 nitro-muriatic acid. The ammoniacal liquor was supersatu- 

 rated with muriatic acid, and boiled with an excess of sub- 

 carbonate of Soda ; the white precipitate of sub-carb. of 

 zinc thus formed, after being well washed and strongly 

 calcined, yielded 0.06 gr. of oxide of zinc on 3 gr. or 

 2.00 per 100. 



The dark coloured precipitate was dissolved, in the hu- 

 mid state, in acetic acid : the solution was evaporated care- 

 fully to a perfectly dry mass, which, after ebullition with wa- 

 ter, was filtered: the peroxide of iron collected on the filter, 

 by calcination with caustic potash, was found to be per- 

 fectly free from manganese; it weighed 0.28 gr. on 3 gr. 

 or 09.333 per 100. 



The manganese was precipitated from the liquor by ebulli- 

 tion with an excess of sub-carbonate of soda ; the precpi- 

 tate, which was colourless, was strongly heated and afford- 

 ed 0.43 gr. of Tritoxide of Manganese, equivalent to 0.397 

 grammes of Protoxide on 3 gr. or 13.233 per 100. 



D. The liquor (C), from which the black precipitate was 

 obtained, when treated with oxalate of potash, afforded a 

 precipitate which, having been decomposed by a strong 

 calcination, gave 0.62 gr.of lime on 3 gr. or 20.666 per 100. 



E. An excess of caustic potash, added to the liquor (D), 

 gave rise to a precipitate of magnesia, which, after expo- 

 sure to a high temperature, weighed 0.140 gr. on 3 gr. or 

 4.333 per 100. 



The constituents of this pyroxene therefore are, 



per 100 parts, 



A. Loss by calcination, 01.166 containing oxygen 



B. Silica 45.333 22.802 



C. Alumina 02.000 



C. Oxide of Zinc 02.000 



C. Peroxide of Iron 09.333 02.861 



C. Protoxide of Manganese 13.233 02.900 



D. Lime 20.666 05.806 



E. Magnesia 04.333 



98.064 11.566 

 100.000 . ■ 



Loss 1.936 



