374 Scientific Intelligence. — Mineralogy. 



and finds that the so-called oxide of aridium is merely oxide of iron, 

 with a little phosphoric, acid and oxide of chromium. — (Journal fur 

 Practische Chemie, ix. 27.) 



12. Density of Selenium. — Schaflfgotch has determined the den- 

 sity of selenium, and deduces from a great number of experiments 

 the following conclusions : — 1st, Selenium has two different spe- 

 cific gravities (at 16 R.), namely, 4-282 and 4*801. The smaller 

 number belongs to an amorphous and glassy condition, the higher 

 one to a granular crystalline state ; the two states may be con- 

 verted into each other at pleasure. 2d, The blood- red flocky Sele- 

 nium, as precipitated in the cold, has the density of amorphous 

 Selenium, whether its colour and apparent volume have been changed 

 by heat or not. — (American Journal of Science and Arts, 2d series, 

 No. 49, p. 123.) 



13. Dolomite. — M. J. Durocher has obtained dolomite artificially 

 through the action of magnesia vapours. He put in a gun-barrel 

 some anhydrous chloride of magnesium, and a porous carbonate of 

 lime, the latter being so placed that it could be reached only by 

 vapours from the former. The gun-barrel was closed, and then 

 kept at a low red-heat for three hours. The limestone, when taken 

 out, was partly scoriaceous externally, and covered with a mixture 

 of chloride of calcium, and chloride of magnesium within ; it was 

 altered mostly to a dolomite, as ascertained by analysis. — (American 

 Journal of Science and Arts, vol. xvii., No. 49, 2d series, p. 128.) 



14. Crystallized Furnace Products. — F. Sandberger has an- 

 nounced the occurrence, as furnace products, of graphite in 6-sided 

 tables near Dillenburg ; metallic copper in threads, and rarely octa- 

 hedral crystals, near Dillenburg ; antimonial nickel in long hexa- 

 gonal needles, at Ems ; galena in cleavable cubes, at Holzappel 

 and Ems ; magnetic iron in octahedra ; 3 Cu 2 O+SbO 3 in copper red 



m 



or yellow hexagonal tables, at Dillenburg ; Ti Cy -f- 3 Ti 3 N 

 Bodensti in. — (American Journal of Science and Arts, vol. xvii., 

 No. 49, 2d series, p. 128.) 



15. Purification of Graphite for Lead Pencils. — Runge pro- 

 poses to purify poor graphite for pencils, by digesting, for thirty- 

 six hours, the finely powdered mineral with about double its weight 

 of concentrated .sulphuric acid, then diluting the acid with water, 

 and washing the powder i'vee from acid. Graphite thus powdered 

 is very much cheaper than the ordinary English, and is quite as 

 pure as the best liorrowdale black-lead. The decanted sulphuric 

 acid contains iron, sulphate of alumina, &c. ; the latter may be 

 separated when large quantities of graphite are operated upon. 

 Runge also proposes to add a little lamp-black with the graphite, in 

 order that the lines made by the pencils may have a deeper shade of 

 Mack. Probably certain kinds of manganese may be used for the 

 same purpose. — (La Technologist^ April 1853, p. 360; Dublin 

 Journal of Industrial Progress, No. I, p. 21.) 



