On the liquefaction and solidification of bodies generally ex­isting as gases

• Published in: Abstracts of the Papers Communicated to the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1851
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1098/rspl.1843.0034; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1843.0034

The method employed by the author for examining the capability of gases to assume the liquid or solid form, consisted in combining the condensing powers of mechanical compression with that of very considerable depressions of temperature. The first object was ob­tained by the successive action of two air-pumps; the first having a piston of one inch in diameter, by which the gas to be condensed was forced into the cylinder of the second pump, the diameter of whose piston was only half an inch. The tubes into which the air, thus further condensed, was made to pass, were of green bottle glass, from one-sixth to one-quarter of an inch in external diameter, and had a curvature at one portion of their length adapted to im­mersion in a cooling mixture: they were provided with suitable stop-cocks, screws, connecting pieces, and terminal caps, all very carefully made, and rendered sufficiently air-tight to retain their gaseous contents under the circumstances of the experiments, and when they were sustaining a pressure of fifty atmospheres, as ascer­tained by mercurial gauges connected with the apparatus. Cold was applied to the curved portions of the tube by their immersion in a bath of Thilorier’s mixture of solid carbonic acid and ether. The degree of cold thus produced, when the mixture was surrounded by the air, estimated by an alcohol thermometer, was a temperature of —106° Fahr. But on placing the mixture under an air-pump, and removing the atmospheric pressure, leaving only that of the vapour of carbonic acid, which amounted only to 1-24th of the former, (that is to the pressure of a column of 1·2 inch of mercury,) the ther­mometer indicated a temperature of 166° below zero of Fahrenheit’s scale. In this state, the ether was very fluid; and the bath could be kept in good order for a quarter of an hour at a time. The author found that there were many gases which, on being sub­jected to cold of this extreme intensity, condensed into liquids, even without a greater condensation than that arising from the ordinary ...