Proceedings of the American Academy of Arts and Sciences. VOL. XLVIII. No. 9. - SEPTEMBER, 1912. CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL THERMODYNAMIC PROPERTIES OF LIQUID WATER TO 80° AND 12000 KGM. BY P. W. BRidgman. CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL LABORATORY, HARVARD UNIVERSITY. THERMODYNAMIC PROPERTIES OF LIQUID WATER TO 80° AND 12000 KGM. Volume of Kerosene as a Function of Temperature and Pressure 356 359 INTRODUCTION. THIS paper is in the nature of a supplement to a former paper on the properties of water in the liquid and the solid forms. The solid forms were studied over a range of 20,000 kgm./cm.2, and from -80° to +76°, but the study of the liquid reached only from the lowest temperature of its existence to about +20°. Above 0°, measurements were made on the liquid at only 20°. The two measurements, at 0° and 20° were sufficient to give the mean dilatation between 0° and 20°, but not the variation of dilatation with temperature. It was assumed in the earlier paper that the variation of dilatation with temperature became negligible at high pressures, since this seemed to be the most plausible assumption in view of all the data then available. In this present paper the study of the liquid has been continued from 20° to 80°, and to 12000 kgm. The pressure range is greater than that of the preceding paper by about 2,500 kgm. The range is not great enough to entirely cover the region of stability of the liquid, but it is as great as it was convenient to cover with the method used here, which is different from that of the former work. It has the advantage of very much greater rapidity of operation, but since it depends on the complete elastic integrity of the steel pressure cylinders it is not possible to reach so high pressures with it as with the former method. [The former limit of 9500 kgm. was set by the freezing of the liquid and was not due to any limitation of the method.] Nevertheless, it may be hoped that the present temperature and pressure ranges are both wide enough to give a fairly complete idea of the nature of the effects to be expected at high pressures with varying tempera ture. Measurements of the dilatation have been made at four temperatures, so that it has been possible to find the variation of dilatation with temperature at any pressure. Perhaps the most unlooked for feature disclosed by the measurements is the fact, contrary to the assumption of the first paper, that the variation of dilatation with temperature does not become vanishingly small at high pressures, but reverses in sign. This means that while at low pressures the volume increases more and more rapidly with rising temperature, at high pressures the expansion becomes more slow at high temperatures. The data of this paper are sufficient to completely map out the p-r-t surface over the domain in question: Both the first and second 1 Bridgman, These Proceedings, 47, 439-558 (1912). |