STATE GEOLOGIST. PAILIL 
and after three months in water showed extreme hardness. Its content 
of water was found to be 19.87 per cent. 
A cement was now prepared with pure kaolin as a basis according 
to the formula: 2(2CaOSiO,)-+ (2CaO) Al,O,. 
The composition of this cement was thus: 
— Per cent. 
Sli Caper ey eee weet ees mere Pea fc NOP ke. ean MAL WZ 
aN aN eo ea Seer ba ik a 18.61 
ELINA Core Seay eer ee ee eae ce i tty Sie a ee ea eel weno aaa 58.89 
INixomestagam declaliGsaniaranmery ae tits Saeyaie ste etatesrre oe" = 1.38 
This cement, when powdered, set in 15 minutes, heating somewhat. 
After go minutes it was extremely hard, and after several months in water 
it was still harder. After 30 days it was found to show 17.05 per cent.. 
of water of hydration. This checked reasonably well with the water of 
hydration calculated from the two separate mixtures previously prepared, 
the di-calcium meta-silicate and the di-calcium aluminate. By calcula- 
tion this cement should contain 16.19 per cent. of water of hydration. 
This kaolin cement was of a pure white color and might serve as an 
example of a white cement. A temperature of cone 18 is said to be 
sufficient for its production. 
One of Zulkowski’s students also examined a commercial Portland 
cement of the composition: 
Per cents. 
Sli Cabeer desea wren cimenia ete Bal EMC Abe ei 2 lee Meets 23.40 
PAULIN URE c epee eka ele een aren BRI cats aces Sek 6.07 
HET CLOG Cheerios Poe sire ewes tay ge a Dell 
TEAUAOVER, 575 oh Meh toniple emcee os ret Eels MAS tings a see Ri Se LE 63.87 
Mision CST Mee ia aerstearsnytte wnohatee nucleate hak Papen veh ae 0.97 
IPOUECIST OWNS Boe Gah SS ea ee eC ae 0.80 
XOXO RE e5.5 ee Ses Sas ae NCE RE BN RS Re ae ee 22 
SHC Oa Te: HA ODIAKG (Gra isicans checoetor aha GS aac chee cis GaN Oa ee 14.5 
which was a cement of excellent quality. 
By calculation, according to Zulkowski’s views, this cement contains: 
61.89 per cent. di-calcium meta-silicate, 
12.14 per cent. di-calcium aluminate, 
4.35 per cent. di-calcium ferrate, 
14.22 per cent. calcium oxide, 
0.97 per cent. magnesium oxide. 
_ This ought to contain accordingly 14.67 per cent of water of hydra- 
tion. On hydration the di-calcium silicate splits off half of its calcitum‘as 
calcium hydrate, the silica remaining as mono-calcium silicate, the alu- 
