350 CEMENT MATEEIALS AND INDUSTRY. [bull. 243. 
Analyses of natural-cement rocks, Akron-Buffalo district, New York. 
Silica (Si0 2 ) 
Alumina (A1 2 3 ) 
Iron oxide (Fe 2 3 ) .. 
Lime (CaO) 
Magnesia (MgO) 
Alkalies (K 2 0, Na 2 0), 
Sulphur trioxide (S0 3 
Carbon dioxide (C0 2 ) 
Water 
1 
2 
3 
9.03 
10.68 
« 33. 80 
2.25 
.85 
| 4.61 
r 3.96 
I .88 
26.84 
25.65 
19.93 
18.37 
17. 93 
9.17 
.85 
n. d. 
n. d. 
n. d. 
n. d. 
.50 
40.33 
.98 
| 41.13 
25.90 
9.85 
3.10 
.87 
26.25 
18.15 
a Called " Silica, clay, and insoluble silicates." 
1. G. Steiger, analyst. Bulletin U. S. Geol. Survey, No. 168. 
2. Lathbury and Spackman, analysts. Letter from manufacturers to writer, 1901. 
3. E. Boynton, analyst. Gillmore, Limes, Cements, and Mortars, p. 125. 
Mr. Heinrich Ries states that two types of kilns are in use at the 
Cummings plant at Akron, Erie County, N. Y. Of 17 kilns in use 
there at the time of his visit 8 were of rectangular cross section, 9 by 
22 feet in area, with a height of 34 feet. The remaining 9 were cir- 
cular in cross section, with a diameter of 9 feet and a height of 34 
feet. 
The crushing practice at the Cummings plant at Akron, N. Y., is 
stated a to include the following processes: 
At this works a general system of reduction is used, consisting of ( 1 ) Sturtevant 
crushers, (2) Cummings pulverizers, (3) ten run of 42-inch underrunner millstones 
faced with chilled-iron plates, and (4) ten run of 42-inch Esopus underrunner mill- 
stones. The material, as it is conveyed from one to another of these sets of crushers, 
is made to pass over screens, whereby such material as has been reduced to proper 
fineness is separated from the mass and is spouted to a general conveyor, which 
finally receives the product from all the grinding machines and conveys it to the 
packing house. 
Each set of crushers, while it furnishes a certain percentage of fin- 
ished product, reduces the entire material to such fineness that what 
is fed to the fourth series is about the size of wheat kernels and very 
hard to reduce. These harder-burned portions make a cement which 
has a much higher tensile strength than the normally burned product. 
The practice at the Buffalo plant, in Erie County, N. Y., is thuj 
described by Ries: 
Both the normally burned and the clinkered material are fed into the grinding 
machinery. The first set of machines are Stedman disintegrators, and the product 
from these is passed over a screen, all that passes through representing the normally 
oRies, H. 
836-837. 
Lime and Cement Industries of New York, Bulletin 44, New York State Museum, pp. 
