ON THE CRYSTALLINE SLAGS. 359 
Crystallized 
Fuchs. Oxygen. by V. Kobell. 
Silica ». 2.24. eeiaha Ra litiovet aie 's st fete lameyee 29°64... 15°38 ........ 310 
PERU Uline lalida iigiididlais eGo iefaMeMO BL EE SB ais cs cies 21° 
I Se Te en's at ey aie oes wee OO Pe ceigie hie 37°4 
(CAA EEVI ES nis ag ri a ia sili aaa 3°4: 
Oxide of iron (eisen oxydoxydul),. 6°56 .......... FeO 44 
RP ee LEY iy os ody 3 i008 CLO bene ge | ee _ 2:0 
99°60 99°6 
Damour. Oxygen 
Bineey Cue ene FG! EPO, 16°18 
Alumina {2.50305 00.9 y. 19°80 '....-. 9°24. \ 11-03 
Sesquioxide of iron...... ak oy ac Red 1°79 
ime peak arate a2 38°11 j 10°83 
Daprepiay).. 2211.5. Ae BOONE OBS PUNE 
2 a ea RR OB ei aeoxey 0:08 
PRVUG ES sires ts hin avaias sath 1°53 
99°54 
Slag 7 Native Gehlenite. Native Gehlenite. 
Fuchs. Damour. 
Oxygen Oxygen. Oxygen. 
Le iganpagtine taf Fm ig) a Nar DC 15°88. oes es 16°18 
Alumina bases.... 11°33 ...... 11°58 ....,. 11°03 
Lime bases ...... DADs emer. DSO Cease. L176 
In slag 7 we may probably be justified in regarding the sulphate of lime and 
sulphuret of calcium as impurities, and in no way connected with the for- 
mula; just as the water, which appears to exist in natural Gehlenite in 
variable proportion, may be similarly regarded. Metallic iron and frag- 
ments of coke being mixed up in the slag, the crystalline plates were care- 
fully selected as free from impurity as possible. 
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 O3)+3Al2 Os, Si O03, 
or as represented by Berzelius’s method of notation, 
nee ne 
which also appears to represent the constitution of Gehlenite more nearly 
‘than 2Ca3 Si+ Al Si, which is usually assigned to it (Rammelsberg, Hand- 
_worterbuch, Theil i. p. 250; second supplement, p. 53). 
_ By contracting the following calculations from the respective formule 
7 
this statement will appear clear. 
4, 2. 
3Ca’ Si+ AP Si 2Cas Si+ Al? Si 
A Oxygen. Oxygen. 
Si 3086 1602 3360 17°44 
Al 25:89 12:07 9498 11°65 
Ca 4367 12:08 41°49 11°63 
Si is taken as 46-22, Alas 51:44, and Ca as 28°52. 
