CEMENT.
478
a No. 40 sieve. The following table shows results of this kind, including also a statement of the losses, in weights:
SPECIFIC GRAVITY DETERMINATIONS ON MATERIAL WHICH HAD BEEN MIXED WITH WATER AND THEN REGROUND.
Remarks.
Set 1 day in air, 6 days in water.
Set 7 days in air.
Set 28 days in water. Set 28 days in air.
Set 1 day in air, 6 days in water.
Set 7 days in air.
Set 28 days in water. Set 28 days in air.
Set 7 days in water. Set 9 days in air.
Set 28 days in water. Set 28 days in air.
Set 24 hours in air.
4 hours retarded.
2»K1
Set 7 days in water.
Set 7 days in air.
Set 28 days in water. Set 28 days in air.
Brand.	Specific gravity.			Loss in weight.	
	Original condi- tion.	After heating to 110° C.	After heating to redness.	Upon heating to 110° C.	Upon heating to redness from 110° C.
				Per cent.	Per cent.
Star, with plaster..		2.47	3.21	10.21	11.10
		2.57	3.17	6.76	8.43
		2.34	3.14	9.20	11.92
		2.59	3.14	4.92	8.14
Star, without plas-		2.40	3.17	14.33	12.35
ter.		2.58	3.18	7.89	9.65
		2.27	3.14	12.83	13.20
		2.56	3.14	4.52	10. 60
		2.47	3.20		11.38
		2.68	3.22	4.68	8.40
		2.38	3.23		13.45
		2.63	3.23		8.90
	2.55	2.62	3.21	8.71	8.47
	2.35	2.36	3.18	9.10	11.34
	2.25	2.27	3.21	12.57	14.79
	2.27	2.29	3.20	12.32	15.53
		2.80	3.21		10.65
					
		2.87	3.16	2. 53	10.21
		2.65	3.14		15.01
		2.86	3.18			11.35
The number of hours retarded in the column of remarks opposite the last three samples of Whitehall cement refers to the interval of time after first mixing with water before the material was put into cubical molds. The cement was reground and retempered with water in the last two. When 30 days old compression tests were made of the cubes, fragments of which were again ground and the determinations as above followed on specific gravity and losses in weight due to heating.
Results on reground material from tensile briquettes, those which set in air and those which set in water, are found in the tables which come next, to which is added a table showing the comparative values thus obtained.