128 Scientific Intelligence. 
1. Specific gravity, ° t : 29052 at 19°-2 C. 
2. fs , f 29152. 19°22; 
3. $ : t sii RO2AD 0“ AOC 
4. Z : : so SOD 8T oS BO 
* From the analyses, the following formula is deduced :— 
Al?02, SiO0?-++-2 (3(Ca, Mg, Mn, Fe) O, SiO). 
The formula differs from that of ae in containing two equivalents 
of the silicate of lime series instea one. Ivanov however has de- 
scribed a mineral from Slatoust, ention | in composition with the pre- 
ceding slags ;* but Professor H, Rosé informs us that the analysis of 
Ivanov has been clearly proved erroneous. Berthier has given the 
results of several analyses of slags from blast furnaces of neasly the 
same composition, but has incorrectly deduced the formula ‘ (Ca, Mg, 
M, f )S+-AS,’ which is that of idocrase. He has also omitted in lis 
analysis of a slag from Dudley, protox yd of ma nganese, potassa. and 
sulphur, which were found in all the preceding analyses of slags from 
the same locality 
Crystalline slag allied to Gehlenite—Slag (No.7) was obtained 
from one of Mr. Dawes’s hot-blast furnaces at Oldbu 
The crystals were thin square pelts the lateral faces of which were 
perpendicular to each other, and to the terminal faces. They appea 
to belong to the prema! stg “They are white, and when very 
thin transparent. dne 
e eonpoaion (atielvans No. 4 below,) approximates very nearly 
to that of Gehlen 
“ The oxygen of the silica is to the oxygen in either the alumina or 
lime bases in the proportion of 4 to 3. This leads to the formula, 
3(3CaO, Si O?)+-3Al? 02, SiO03, 
or as represented by Berzelius’s method of notation, 
3Ca3 Si+Al Si, 
which also appears to represent the constitution of Gehlenite more 
nearly than 2Ca? Si+ Al? Si, which is usually assigned to it.”F 
‘« Admitting this slag to be really Gehlenite, the circumstance of it its 
production at a high temperature in an iron farn ace, ma ibly be 
made available by the geologist in explaining the ifevaet of the rocks 
in which the natural mineral occurs in Fassathal in the T 
Crystalline slag allied to Humboldtilite—No, 8 was also oa Mr. 
Daw It was obtained during the process of remelting cast iron with 
lime ina shall 6 ola. 
t is a mass of oan. -gray slag containing imbedded long yellow crys 
tals, which appear to be square prisms with the angles truncated ; cleav- 
able perpendicular to the axis of the prism. In part of the specimen 
the crystals are very fine and radiated, 
“ Without attempting to extort from the analytical results a pre ise 
i¢ expression, we may state that probably the formula nee anced 
* "Hanmelbrg Part ii, p. 258, and first supplement, o WEhe sinks 
t nelsber; ; Handworterbuch, Theil i, p. 250; sfcnd pple» 
