STUDIES OF THE VAPOR PRESSURE OF SOLUTIONS. A STATIC METHOD FOR THE DETERMINATION OF THE DIFFERENCE BETWEEN THE VAPOR PRESSURE OF SOLUTION AND THAT OF SOLVENT
Journal of the American Chemical Society
The fundamental importance of accurate determinations of the effect of dissolved substances on the vapor pressure of solvents, and the lack of agreement of results obtained by different workers using dynamic methods, led the authors, in the spring of 1912, to undertake the problem of improving the static method with the view of making it a method of precision. After some preliminary experiments, they decided to apply the principle of the Rayleigh manometer. This instrument was designed by Lord
... s designed by Lord Rayleigh for the purpose of measuring small differences in gas pressure. It is used by the authors to measure the difference between the vapor pressure of the solution and that of the pure solvent. The work so far has been limited to aqueous solutions of mannite a t 20'. R R are glass bulbs, about 39 mm. in diam., blown on a glass fork. This is connected by means of a rubber tube with a mercury reservoir which may be adjusted very accurately a t any desired height by means of the screw I. At the centers of the bulbs are set two glass points. The side limbs P P communicate with the systems, the relative pressures in which are to be measured. The essential features of the manometer are shown in Fig. 5 . 12. physik. Chem., 37, 713 (1901); Trans. Royal SOC., 196, 205 (1901).