Abstract
In an article published in 1967 in this journal, an initial theoretical formula has been proposed to represent the variation of the water density as a function of the variations of its isotopic composition. Following this article, an experimental programme has been undertaken with the purpose of checking the validity of the formula. Limited at first to a density interval of 2·10-3 kg·m-3, this study was then enlarged to a ten times greater interval. As a consequence, the formula has been revised, so that it is more suitable for this new interval of density.
Experimental observations have been made on the density and the isotopic composition of various water samples. The variations of density have been determined by observing the buoyant force exerted by each sample of water on a stainless steel cylinder. The isotopic composition has been determined by mass spectrometry.
The law of variation of the water density as a function of its isotopic composition, deduced from our observations, is slightly different from that obtained by the theoretical formula.