422 Scientific Intelligence. 
being that Loa here replaces the glucina. Analysis 2 affords very 
nearly this form 
The form is Bainiea to that of beryl. -The inclination of the pyra- 
midal planes on the lateral faces of the hexagonal prism according to 
Koch is 103° 15/ 46”, or on O (the base) 166° 44’ 14”. This plane 
referred to the beryl type is, the plane 2.t 
(2.) Gehlenite Slag.—Among the slags of iron furnaces, 4-sided rect- 
angular prisms or tables are not uncomm D. Forbes first pointed 
out a slag in 4-sided prisms which was near Humboldtilite. Haus- 
mann has described similar slags. ammelsberg refers a slag from 
Oldbury, England, described by. Perey, to Gehlenite, it giving the com- - 
position 3R* Si+ Ai Si. A slag from near Homberg, analyzed by Bun- 
sen has a similar constitution. “Tt occurs in tabular or oblong prisms, 
of a pearl gray color, glassy or pearly lustre, sometimes translucent ; 
G.=2-876, H.=6. B.B. in the forceps fuses with some difficulty to @ 
dai sng Bunsen’s analysis afforde 
Oa Mg Mn K Na : 
92-59 17°81 17-35 5-57 2°67 3°05 — 
whence the formula 2k Si+ Ale Si. 
Rammelsberg has analyzed and described some se from Ma des- 
prung in the Anhalt Hartz,i where the ores are spat hie and specular 
iron and lirgonite. He obtained for the formula ke (Si, 41)*; pone 
Scheerer’s view that 341 replace Si. ell is similar to — alu 
ous A hone nes. The crystallized and g ncn gave e the sa ers 
of dimorphism. Von Kobell Phnaee wrote for the form es of Geh- 
lenite pay (Si, Al)? ; and this is — to the cme g of per 
Section 
No. 2, viz .R? Si? +8 Sit; it differs mainly in ontaining protoxyd of iron in place 
ei ’ o Oxyd 0 Lage 
of lime, hist beret ey thdretoie afford lie that ” Wichtyne is hexagonal in 
zati 
4 It is pray of interest to compare the form with that of Nepheline. In say. 
) : $= 166° 253’, which differs 184’ from the inclination of the p 
lis 16 
= analyses of the Midgichtang slags by Rammelsberg gave rat xygen 
e per-centage of silica was about 4 ~ 0; and the ratio between the ox} 
of “all the faite: and that of the silica, was nearly 3 : 4, instead of 6: 4, 
ite ratio. Rammelsberg deduces for the ratio between the oxygen of the pro yds 
at o tami i i He : ei 
: tio. 
Gehlenite has the oxygen ratio for R, # & hich gives 6:4 or 3: 2 . 
Sc, oxygen of the bases and silica; while iatiacke bis the eee ratio 6: eee 
roading to to 1:1, between the bases and silica, thus differing widely from 
The 
lenite formula of Gehlenite based on the ratio 3:2 wo 
(R448) Si®—Re Si? 8)", and that of Humboldtilite (¢R*+4#) Siok? Bi BBL 
There i is as yet no good evidence that alumina replaces silica in Gehlenite. : of 
ene, Humboldtilite and Gehlenite appear rather to be to different sections 
elias the fit to the Augie, the sto rat the Game, meee to which Scapolite per 
the Andalusi te section—s. D, 
