STATE GEOLOGIST. 369 
portions of the constituents. Cement made from very finely-ground ma- 
terial, and thoroughly burned, may contain much more lime than the 
amount usually present and still be perfectly sound. On the other hand, 
cement low in lime may, on account of careless preparation of the raw 
material, be of dangerous character. Further, the ash of the fuel used 
in burning may so greatly modify the composition of the product as 
largely to destroy the significance of the results of analysis. 
7. Method.—As a method to be followed for the analysis of cement, 
that proposed by the committee on uniformity in the analysis of materials 
for the Portland cement industry, of the New York section of the Society 
for Chemical Industry, and published in the Journal of the Society for 
January 15, 1902, is recommended. ; 
SPECIFIC GRAVITY. 
8. Significance.—The specific gravity of cement is lowered by 
underburning, adulteration and hydration, but the adulteration must be 
in considerable quantity to affect the results appreciably. 
g. Inasmuch as the differences in specific gravity are usually very 
small, great care must be exercised in making the determination. 
10. When properly made, this test affords a quick check for under- 
burning or adulteration. 
JJ. Apparatus and Method.—The determination of specific gravity 
is most conveniently made with Le Chatelier’s apparatus. This consists 
Orc iaske (DD) Cisunes738)) ‘of 20) culcm: (72.32) cu, ind) capacity, the 
neck of which is about 2 cm. (7.87 in.) long; in the middle of the neck 
is a bulb (C), above and below which are two marks (F) and (EF); 
the volume between these marks is 20 cu. cm. (1.22 cu. in.). The neck 
has a diameter of about 9 mm. (0.35 in.), and is graduated into tenths 
of cubic centimeters above the bulb. 
12. Benzine (62° Baume) naptha, or kerosene free from water, 
should be used in making the determination. 
13. The specific gravity can be determined in two ways: 
(1.) The flask is filled with either of these liquids to the lower mark — 
(E), and 64 gr. (2.25 0z.) of powder, previously dried at 100° C. 
(212° F.) and cooled to the temperature of this liquid, is gradually 
introduced through the funnel (B) the stem of which extends into the 
fiask to the top of the bulb (C)), until the upper mark (F) is reached. 
The difference in weight between the cement remaining and the original 
quantity (64 gr.) is the weight which has displaced 20 cu. cm. 
i, (2) Wine whole quantity of the powder is introduced, and the 
level of the liquid rises to some division of. the graduated neck. This 
reading plus 20 cu. cm. is the volume displaced by 64 gr. of the powder. 
24—S. G. Bull. 3. 
