ON THE CRYSTALLINE SLAGS. 361 
lime, the sulphuric acid, produced by the oxidation of the sulphur existing as 
sulphuret, was determined by the addition of acetate of baryta. 
1. Weight of slag 25°46 grains. 
2. Alumina 2°95. 
3. Sulphate of lime 24°27. 
4, Oxide of manganese 0°25. 
5. Sesquioxide of iron 0°34. 
6. Sulphate of baryta 1°44. 
Analysis tabulated. Per cent. Oxygen. 
Se ee Re ery ABO WTI, HB 23°68 
Alumma .....2 02.05... PSB RNS..ed, ERS 
i ee ee a 38°20 10°73 
Protoxide of manganese .. 0°91 .... 0°20 > 11°18 
Protoxide of iron........ PED A k O85 
Sulphuret of calcium .... 1°76 
Error of loss............ 0°55 
100°00 
Without attempting to extort from the preceding analytical results a pre- 
cise atomic expression, we may state that probably the formula of Hum- 
boldtilite, as deduced from the analysis of Von Kobell (Rammelsberg, 2nd 
part, p. 308), nearly represents the constitution of this slag. The formula 
in question is 
3R2Si+ R Si. 
_ We introduce Von Kobell’s analysis (Rammelsberg, Ist part, p. 314) :— 
Oxygen 
Sei Gi dbe sis voile, x .- aed bv. 6 AB OG jniycs)- deny 44>» 21°83 
Die | nea Siri ta 31°96 .... 897 
BEEN Mul slp cats GLO peice) OO 11°86 
Protoxide of iron........ 232 .... 0°53 
MA | os ey 120. awd d- aael-, 228 
ee ee Peele fh 3 ADS vie adh whi Pibgiae 4 1:09 
en oe elena tahictngs,< 0°38 ‘ 0:06 
: 10020 | - 
‘The per-centage composition calculated from the formula would be,— 
rite Lem 52) th 45°37 
Alumina.......... 1262 
Lime ............ 41°99 99°98 
Damour assigns a different formula for Humboldtilite, which he believes 
© be identical with Mellilite*; and this formula is precisely that which we 
lave given for the first series of blast-furnace slags. For the sake of com- 
arison we subjoin Damour’s analyses. 
Mellilite. Humboldtilite. 
nig Oxygen. 
Memied ek. SF eetites wee ss SOO... Ye 21°13 
welumina...-....... 6°42 .. 2:99 610 443 .. 2:06 5 
 Sesquioxide of iron.. 10:17 .. 311 10°88 .. 3:33 f 99 
Se 82-47 ., 312 162 81°81. 8921 1, 
_Magnesia.......... 6°44 .. 2-50 5°75 .. 222 
ra oS ESG Ae eatatet ae Dei caries 0 (6) a Bsa ade 0°06 
ae SARA SURO REE 2c. SOE 112 
' 98°18 98-35 
1846. 2B 
