TABLE 106.-Apparent weight of water in air [This table gives the apparent weight for temperatures between 15° and 30° C, humidity 50 percent, unreduced barometer reading 76 cm, of certain volumes of water weighed with brass weights. The table may be conveniently employed to determine definite volumes of water for calibrating instruments. The air is assumed to be at the same temperature as the water] TABLE 107.-Temperature correction for glass volumetric apparatus [This table gives the correction to be added to actual capacity (determined at certain temperatures) to give the capacity at the standard temperature, 20° C Conversely, by subtracting the corrections from the indicated capacity of an instrument standard at 20° C the corresponding capacity at other temperatures is obtained. The table assumes for the cubical coefficient of expansion of glass 0.000025 per degree centigrade. The coefficients of expansion of glasses used for volumetric instruments vary from 0.000023 to 0.000028] TABLE 108.-Reduction of weighings to vacuo The weight of a body in vacuo is determined by adding to its apparent weight in air a buoyancy correction equal to the weight of the air displaced by the difference in volume of the body weighed and the weights required to balance it on an equal-arm balance. |