PHYSICAL AND CHEMICAL PROPERTIES. 
PARTS IV, V. 
145 
and the commercial product seldom gives a higher strength than 
450 pounds per square inch in mortars composed of 1 cement to 
3 standard sand. 
It is probable that perfectly fused Portland 
cements would be capable of attaining a higher strength than 
the sintered product of the present commercial practise. 
TABLE XXXVIII.—Properties of fused mixtures containing calcium oxide 
and various amounts of silica, alumina, and iron oxwide. 
Tensile 
Melting Time of Soundness of neat Seer 
No.| Molecular proportions. | point in| Raw materials. sete and sand mor- |sandmor- 
degrees. Prareen tarsin water. jtars after 
28 days in 
water. 
Bo PC@aO ISOs: === == 52 - == =| 1,300 | CaSO4+SiOz -__ (a) Disintegrated ___- 0.0 
|| PLOETOY aISy 0) Seer eee e1,900 | CaO+SiOz2--_-_- AT || Somat sce 150 
3 | 2.5CaO, 1SiO2> 41,900 |-----! doyt= a4 480+ |_--_- does saeos 390 
Aa tSCaAO 1 SiOob: - = 2 ee 41,900 |_---- doe ee 480— | Disintegrated -____ 0.0 
Bye Ca@ et AleOs = 2222-2 2 1,500 | CaCO3+Al203 __ Rar || Sob) 795 
6 | 2CaO, 1Al20s -- 1,450) |----< (s (oye (O) Feast dO) S222 25225522 315 
Tae bCa@ PAs Og === sa ene RAB OM pee doye-eeae=-2! (e) Soundifseasoned_| 105 
8 | 8CaO, 1Al2Os ___-.--_---__- 1,450) |---=2 dope see os (e) Disintegrated ___- 0.0 
9 | 1CaO, 1Fe203_- 1,450 | CaCOsFe203_---| 360+ | Sound —---_------- 120 
10 | 2CaO, 1Fe203_____--_-_---- T5600 IN | seen Ch) coe ase 360+ |----- 028222 essen e 15 
i SCaO! 1he2Os_- === === SEES) jean dot 22-2 =2 10 Disintegrated _-__- 0.0 
12 | 8CaO, 18i02+4.2 per cent! 1,600 ; CaO+Si02— 120+ | Disintegrated but} £585 
Al203. AlzO3. sound after sea- 
4 soning. 
13 | 8CaO, 1Si02+5.0 percent | 1,600—|----- GO jasteasee8 x Soundies==eae=aeee 535 
AlOs. 
14 | 3CaO, 1Si02+7.1 percent | 1,600—\----- dojseneas==es XG | ane dO csssc- ease 525 
Al2Os. 
15 | 8CaO, 1Si024-8.5 percent | 1,500 |----- dojss2- 222-4 Parad see Osea aes 615 
Al2O3. 
16 | 2.5CaO, 1S iO +25C a0, x 4 parts of fused 420), \/-n222 ors anes 420 
1Al203. 2.5 CaO, 1 
SiO-+ Ipart of 
fused 2.5CaO, 
1AL03. 
Ap aaa Oe sae eo x CaO, SiOz, and A200 Seen do}. 22- 2 35.5 610 
Al20s. 
8 Failed to set. © About. © Almost instantaneous. 
b Stable modifications. 4 Above. f After seasoning. 
The extraordinary strength of the mono-calcium aluminate 
is also especially noteworthy; and, taken as a whole, the experi- 
ments of Schott must be considered as definite proof of the in- 
competency of the ultimate chemical analyses to reveal the true 
nature of commercial Portland cements. 
Schott took no measurements of the constancy of the volume 
of these indurated sound calcium compounds. 
However, the 
