128 Scientific Intelligence. 
The origin of the globules is attributed to the tendency of feldspar 
to crystallize, and the indirect action of excess of silica present. 
There is an analogy between them and the so-called perlites and _reti- 
nites. Feldspar never takes the globular form, except in rocks rich in 
silica. The rock contains specular iron. Delesse concludes that the 
silica was introduced, subsequent to the first origin of the rock. It oe- 
curs either in veins or intimately mixed with the rock material. Other 
rocks may beome pyromerides through a penetration with silica. 
Pitchstone from the trap of Isle Royal—The following analysis is 
by Foster and Whitney (Rep. Lake Superior, Part ii.) : 
Si Al Fe Ca Mg Na, trace of K TL 
62°51 11-47 11:05 267 2°11 3°03 (loss) 714 
Crystallized Furnace Products —F. Sanneercer has announced the 
occurrence as furnace products, of graphite in 6-sided tables near Dil- 
lenburg ; metallic copper in threads and rarely octahedral crystals, near 
Dillenburg; antimonial nickel in long hexagonal needles, at $5 
lena in cleavable cubes, at Holzappel and Ems; magnetic iron in octa- 
dra; 3Cu? O+SbO? in copper red or yellow hexagonal tables, at Dil- 
lenburg; Ti Cy+3Ti2N in Bodenstein. 
Fibrous amianthoid substance, a furnace product from Westphalia.— 
Scunasex obtained for this substance, 
Si 98-13, Al 1-24, Ca 0-46, Mg and Fe a trace, =99-88 
G, =2:59.—(Pogg. Ann., Ixxxv, 462.) 
Dolomite.——-M. J. Durocuer has obtained Dolomite artificially through 
the action of magnesia vapors. He put in a gun barrel some anhy 
drous chlorid of magnesium and a porous carbonate of lime, the latter 
being so placed that it could be reached only by vapors from the for- 
mer. e gun barrel was closed and then kept at a low red heat for 
three hours. The limestone when taken out, was partly scoriaceous 
i hlo- 
rid of magnesium. Within, it was altered mostly to a dolomite, as as- 
certained by analysis. 
Pseudomorphous Minerals :— 
Pinite after Labradorite.—Resembles a yellowish gray talc-like mi- 
ca. H.=2:5,G.=2-832. Analysis by A. Knop and W. Knop, (Pharm. 
Centr. 1852, 165; Lieb. u. Kopp’s Jahresb. f. 1851, 822): 
Si Al Fe. Ge... ce co Ne Fl H 
5518 2751 408 029 192 $386 4-49 00T 374—=99°94 
Formula deduced, B3 Sit+-5A1 Si+sit, 
