抄録
Sources of errors attached to the pycnometry of sea water such as the variation of surface tension aroused by the varied condition of the glass surface of the hydrometer, by the contamination of water surface due to dust, oil etc. or by the convection in the water specimen, also with personal error, which are superposed in complexed manner, were investigated carefully. As the result of statistics and the experiments on the effects of the contamination of water surface etc. it was shown that the accuracy of the density measurement by means of the Akanuma's Hydrometer is usually of the order of 0.1‰ S.
