Four independent sets of specific gravity measurements are intercompared relative to a least squares polynomial in temperature and salinity over the range - 2 to 30°C and 8 to 40‰. Within this range, individual measurements have a standard deviation of 7.1 ppm about the regression polynomial. Over most of the range, the polynomial formula has a standard deviation of 1 to 3 ppm. The data sets are marginal in defining specific gravity below 0°C and above 25°C and inadequate below 10‰ salinity.