Mineralogy and Geology. 129 
boldtilite, as deduced from the analysis of von Kobell,* arse repre- 
sents the constitution of this slag.t The formula in question 
3R? Si+RSi. 
“Damour assigns a different formula for Humboldtilite, which he 
believes to be identical with mellilite; and this formula is precisely 
that which we have given for the first series of blast-furnace slags.t 
No. 7. | No. 8. | 
Analysis. Oxygen. | = Oxygen. 
Silica,  - . . . worse - 14-71 45-59 > 23-68 
Alumina, , ¥ : 24:24 + + 11-33 166 ht C18 
a F . , ° . 40-12 38-20 
#gnesia, : 2:79 _ i i ; 
Penosya. of manganese, 0-07 at 0-91 <9 ee 
- Protoxyd of ir 4 0-27 Fl 
Potassa with a trade ‘of'soda, ig, Gamer meuareme, | b | oe 
Sulphate of lime, 0°26 —— 
Sulphuret of calcium, — - 3:38 1-76 
“ Berzelius remarks on Damour’s Se lee that ‘in designating by r 
the bases with 1 atom of oxygen, and by R the bases with 3 atoms of 
oxygen, the formula 278+-RS wi ill be obtained, which expresses a 
omewhat rare kind of composition.” ’ 
__ Crystalline slags, allied to Pyroxene.—Nos. 9 and 10 were commu- 
nicated by M. Krantz, the well-known siderskaces " Berlin. They 
Were labelled, Olsberger Furnaces, on the Rhine. 
contains a drusy cavity ba projecting crystals, which are 
Bot sufficiently bright for measurement with the reflective goniometer. 
a 
Hardness —5. No. 10 is-a mass exhibiting a radiated crystalline 
Structure, the individuals of which are too small for measurement. 
ardness — 5°7. p 
To one side of each of these specimens are attached minute scales 
f graphite 
of 1. 
The analyses gave the following results :— 
s No, 9. 
No. 10, 
Pilih, th . ; 53:37 >=: + SOG 
alumina, . ; SiZ * : 4°76 
/ = Lime, Ets OBIS aa ee 
Sea as Ma agnesi ja PA 9°50 + . 4 
 Protoxy d of manganese, * PER Ce A coe 
i Protoxyd ofiron, ° . 005° ~*~ 2 1:48 
oe 101 100-60 
“Wi ith the exception of a few small aot of in a drusy cavity in - 
o , the crystallization of the two preceding slags is confused, so that w 
ngs hope to deduce from their composition a salisfactory 
fru The oxygen of the acid being ana double that of the 
- saeiewemet na Mineralogy, p- 359. 
oo this an. 8 
a ‘} Ibid, p. an Alger's Mineralogy, 6a. 
Bisons fassas, ¥ Vol. ree. No, 13.—Jan., 1848. 17 
