487
CEMENT.
In the following table are the results on material in the cake, set in air, which was exposed to different temperatures while setting. One-quarter of a 2" cube was used in each determination.
Brand.	Specific gravity and marks of identification, cubes which set in air at temperatures of—					
	70° F.		36° F.		0° F.	
	Specific gravity.	Marks.	Specific gravity.	Marks.	Specific gravity.	Marks.
Star		2.181	Feb. 8	2.233	Jan. 22	2.190	Feb. 8
Storm King		1.961	Feb. 4	2.084	Jan. 24	2.224	Jan. 28
Alsen		1.978	Feb. 19	2.093	Feb. 19	2.036	Feb. 6
Josson		1.932	Feb. 20	2.138	Feb. 20	2.012	Feb. 15
Steel		1.705	Feb. 21	1.797	Feb. 21	1.749	Feb. 13
Austin		1.869	Feb. 12	1.832	Feb. 12	1.940	Feb. 6
Bonneville Improved		1.605	Feb. 18	1.793	Feb. 18	1.820	Feb. 7
Hoffman		1.618	Feb. 11	1.938	Jan. 25	1.908	Feb. 11
Norton		1.579	Feb. 23	1.790	Jan. 21	1.911	Jan. 19
Obelisk		1.659	Feb. 16	1.931	Feb. 16	1.884	Feb. 7
The marks indicate the dates on which the cubes were made. Those of the same brand and date came from the same batch of mixed material.
The results which next follow were obtained on material in the cake as described for the last table, but drying each sample before determining its specific gravity by heating for three hours at the temperature of 110° C.
	Specific gravity and marks of identification, cubes which set in air at temperatures of—			
Brand.	70° F.		0° F.	
	Specific gravity.	Marks.	Specific gravity.	Marks.
	2.071	Feb. 8	2.003	
	1.953	Feb. 4	1.912	
	1.887	Feb. 19	1.875	Feb. 6
	1.910	Feb. 20	1.750	Feb. 13
	1.564	Feb. 21	1.380	
	1.564	Feb. 12	1.538	Feb. 12
	1.577	Feb. 18	1.466	Feb. 7
	1.606	Feb. 11	1.505	Feb. 11
	1.558	Feb. 23	1.512	
	1.653	Feb. 16	1.483	Feb. 7
				
In the next table are shown results obtained upon material in the cake which was mixed with large quantities of water. The inner portions of 2" and 4" cubes furnished the samples on which the determinations were made. These grout mixtures were allowed to remain in the mixing bed different periods of time until the water was absorbed by the cement and a pasty state acquired, when the material was placed in the molds. The column headed “Hours retarded” states the interval between the time of mixing and when the material was put into the molds. The specific gravity determinations were made when the cubes