18,2 King: Philippine Concrete and its Aggregates 123 
Specific gravity. — Sixty-four grams of the dried sand were 
introduced into a Le Chatelier flask filled to the zero mark with 
95 per cent alcohol. The rise of the meniscus on the graduated 
neck represents the volume displaced by the grains of sand. 
Dividing the mass of the sample used by the displacement in 
cubic centimeters indicated on the neck of the flask quickly and 
accurately gives the specific gravity of the sand. 
For determining the specific gravity of the coarse aggregate 
about 1,000 grams of the dried gravel were accurately weighed, 
and then allowed to rest under water for twenty-four hours 
in order to fill the pores. After the aggregate was saturated 
with water, it was quickly dried with a cloth, then with a blot- 
ter, and the displacement of the gravel noted in a large graduated 
cylinder containing a measured quantity of water. The specific 
gravity was calculated from the well-known formula: 
Mass 
Specific gravity= 
Volume 
Granulometric analysis. — In determining the granulometric 
analysis of sand, 200 grams of a representative sample were suc- 
cessively shaken on a series of sieves ranging from 10 to 200 
meshes to the linear inch and the residue on each sieve was 
weighed. The sieves are 8 inches in diameter and fitted with 
double-crimped, brass, wire cloth having square mesh openings. 
In Table 4 are recorded the actual mesh and wire sizes, obtained 
by examining the sieves under a microscope fitted with an ocular 
micrometer. The granulometric results obtained during the 
period 1908 to 1914 were secured by hand sieving; results after 
1914 were gotten by using an electrically driven sieving ap- 
paratus commercially known as The Per Se Testing Sieve Agita- 
tor manufactured by Howard and Morse, of Brooklyn, New York. 
Table 4. — Mesh, space, and wire sizes of sieves used in performing granu- 
lometric analyses of Philippine sands. 
