Turning to the other end of the scale of solubility, the most valuable liquids for serving as seals of gasholders, &c., are readily discernible. Far superior to all others is a saturated solution of calcium chloride, and this should be selected as the confining liquid whenever it is important to avoid dissolution of acetylene in the liquid as far as may be. Brine comes next in order of merit for this purpose, but it is objectionable on account of its corrosive action on metals. Olive oil should, according to Fuchs and Schiff, be of service where a saline liquid is undesirable; mineral oil seems useless. Were they concordant, the figures for milk of lime would be particularly useful, because this material is naturally the confining liquid in the generating chambers of carbide-to-water apparatus, and because the temperature of the liquid rises through the heat evolved during the generation of the gas (_vide_ Chapters II. and III.). It will be seen that these figures would afford a means of calculating the maximum possible loss of gas by dissolution when a known volume of sludge is run off from a carbide-to- water generator at about any possible temperature. According to Garelli and Falciola, the depression in the freezing-point of water caused by the saturation of that liquid with acetylene is 0.08° C., the corresponding figure for benzene in place of water being 1.40° C. These figures indicate that 100 parts by weight of water should dissolve 0.1118 part by weight of acetylene at 0° C., and that 100 parts of benzene should dissolve about 0.687 part of acetylene at 5° C. In other words, 100 volumes of water at the freezing-point should dissolve 95 volumes of acetylene, and 100 volumes of benzene dissolve some 653 volumes of the gas. The figure calculated for water in this way is lower than that which might be expected from the direct determinations at other temperatures already referred to; that for benzene may be compared with Berthelot's value of 400 volumes at 18° C. Other measurements of the solubility of acetylene in water at 0° C. have given the figure 0.1162 per cent. by weight.