STATE GEOLOGIST. B71 
on certain sieves. Those known as the No. 100 and No. 200 sieves are 
recommended for this purpose. 
21. Apparatus.—The sieves should be circular, about 20 cm. (7.87 
in.) in diameter, 6 cm. (2.36 in.) high, and provided with a pan, 5 cm. 
(1.97 in.) deep, and a cover. 
22. The wire cloth should be woven (not twilled) from brass wire 
having the following diameters: 
. No. 100, 0.0045 in.; No. 200, 0.0024 in. 
23. This cloth should be mounted on the frames without distortion ; 
the mesh should be regular in spacing and be within the following limits: 
No. 100, 96 to 100 meshes to the linear inch. 
No. 200, 188 to 200 meshes to the linear inch. 
Be Mitty shams. (1476 O29) OF TOO et. (3.52 oz.) should be used 
for the test and dried at a temperature of 100° C. (212° F.) prior to 
sieving. 
25. Method.—The committee, after careful investigation, has 
reached the conclusion that mechanical sieving is not as practicable or 
efficient as hand work, and, therefore, recommends the following method: 
26. The thoroughly dried and coarsely screened sample is weighed 
and placed on the No. 200 sieve, which, with pan and cover attached, is 
held in one hand in a slightly inclined position, and moved forward 
and backward, at the same time striking the side gently with the palm 
of the other hand, at the rate of about 200 strokes per minute. The 
operation is continued until not more than one-tenth of one per cent. 
passes through after one minute of continuous sieving. ‘The residue is 
weighed, then placed on the No. 100 sieve and the operation repeated. 
The work may be expedited by placing in the sieve a small quantity of 
large shot. ‘The results should be reported to the nearest tenth of 1 per 
cent. 
NORMAL CONSISTENCY. 
27. Significance.—The use of a proper percentage of water in 
making the pastes* from which pats, tests of setting and briquettes are 
made, is exceedingly important, and affects vitally the results obtained. 
28. The determination consists in measuring the amount of water 
required to reduce the cement to a given state of plasticity, or to what 
is usually designated normal consistency. 
29. Various methods have been proposed for making this deter- 
imination, none of which have been found entirely satisfactory. The 
committee recommends the following: 
30. Method. Vicat Needle Apparatus. —This consists of a frame 
(K), (Figure 79) bearing a movable rod (L), with the cap (A) at one 
«The term ‘“‘paste”’ is used in this report to designate a mixture of cement and water, and the 
word ‘‘mortar”’ a mixture of cement, sand and water. 
