GEOLOGIC APPLICATION OF THE AIR PYCNOMETER: A STUDY OF THE PRECISION OF MEASUREMENT
Specific gravity of weighed specimens can be obtained by volume displacement of air. The method is safe, rapid, and convenient, and is applicable to masses and powders. Precision, based on the air pycnometer alone and given by the standard deviation of replications, is 0.003 to 0.004. This is adequate for mapping the distribution of specific gravity in the granitic rocks of the batholith of southern California where within-localities standard deviations range from 0.004 to 0.02.