CEMENT,
474
CHEMICAL ANALYSES OP CEMENTS.
Brand.	Class.	Silica.	Oxide £״. iron.	Alum- ina.	Lime.	Mag- nesia.	Oxides of sodium and potassium.	Sul- phur tri- oxide.	Man- ga- nous oxide.	Car- bon di- oxide.
			2. 91	11.20	59.00	3.25		1.40	0.38	1.34
		18.32	3.36	11.22	60.00	3.78		1.40		1.92
		20.76	1.76	6.68	62.00	4.63		1.21		2.86
		do		23.84	1.30	8.12	61.58	2.48		1.60		1.08
Star, earlier man-		do		22.00	2.76	9.67	57.00	3.42		2.07	.45	
ufacture.		do		22.00	2.50	9.00	59.90	3.50		1.98		.75
Star, without		do		22.45	2.53	9.27	60.27	3.59		.60		
plaster.		do		22.94	2,90	6.30	43.74	20.72		2.83		1.00
		do		20.30	2.95	10.87	62.15	2.51		1.10		. 12
		20.42	2.10	11.00	57.50	2.53		2.26		
		do		20.04	3.95	7.48	63.02	1.23		1.62		3.00
			2.68	7.92	62.36	1.15				3.35
		22.92	2.46	7.98	63.39	Trace.		1.28		1.97
		30.98		14.82	43.00	4.16		3.44		3.60
Cathedral		Portland com-	57.76	.98	3.60	34.13	1.04		1.00		1.49
	posite.	23.10	.92	4.74	41.77	9.85		.66		19.00
			2.56	6.22	40.64	25.80		2.91			1.47
		19.02	1.24	8.96	41.18	26.58		1.27		1.75
Bonneville Im-		do		30.40	2.60	10.36	52.12	.21		1.24		3.07
proved.		25.00	2.27	8.93	39.30	16.18	4.26	1.40		2.66
		do		27.70	1.86	7.06	37.00	22.63		1.23		2.46
Newark and Ros-		do		28.71	3.60	5.88	27.00	30.00			1.30		3.52
endale.		do		26.66	3.02	11.48	38.33	16.41		1.35		2.75
		do		23.70	3.30	16.70	37.00	15.30		: 1.98		2.00
		32.00	2.70	8.79	S3.89	18.10		; 1.31		3. 20
										
CHEMICAL ANALYSES OF CEMENT ROCK.
Description.	Silica.	Oxide of iron.	Alu- mina.	Lime.	Mag- nesia.	Sul- phur tri- oxide.	Humus and water.	Car- bon diox- ide.
Cement rock, used by Bonneville Port-	23.20	2.00	6.52	34.20	1.90	.20	13.63	18.40
Limestone, used by Bonneville Port-	1.08	.27		54.80	.52		2.38	40.86
Dark cement rock, used by Newark and Rosendale Lime and Cement Co.	22.69	3.28	5.52	20.90	13.75	.96	7.20	25.70
FINENESS OF GRINDING.
The fineness of the cements was determined by the usual method of sifting and by means of a winnowing device. The_ sieves employed included an ordinary nest of laboratory sieves, fine wire cloth, and silk bolting cloth; also a special brass wire cloth sieve, electroplated to reduce the size of the meshes. The number of meshes per square inch and their sizes are shown in the following table: