STATE GEOLOGIST. 359 
is close to the stopcock, h, and the latter closed. The stopper, s, is now 
removed and 30 grams of cement poured into the bottle, shaking 1t some- 
what. The stopper is now replaced, opened and f lowered till the alcohol 
reaches the mark m. After 3 minutes the volume of the cement can be 
read off the burette. From the volume and the weight of the cement the 
specific gravity is readily calculated from the formula 
s=— 
V 
or it may be read off from a table. In this formula s represents the 
specific gravity, g the weight of the cement and v the volume displaced. 
Liter Weight.—A constant of considerable significance, though not 
generally employed, is the weight of unit volume of cement, say one liter, 
Fig. 77. Apparatus for determining weight of one liter of cement. 
the cement being loose in the vessel employed for this purpose, not shaken. 
The liter weight is determined by placing a funnel over a copper vessel 
whose diameter is equal to its height and which contains exactly one 
liter. The lower part of the funnel is provided with a coarse sieve and 
the bottom of the funnel tube is 5 cm. above the edge of the vessel. 
Cement is now poured into the funnel in small quantities and when a 
cone is formed touching the funnel tube the excess of cement is scraped 
