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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1897 Excerpt: ... obtained as near as possible to this temperature, among a series of capillary-tubes delivered by Geissler, I have chosen the narrowest one, the radius of which was 0,0441 mM. The pure carbonic acid was obtained in a way already described. A first quantity of this purified gas showed following ascensions: t = 12,8 h = 15,36 mM. d = 0,78 mM. 14,5 13,92 0,74 16,5 12,30 0,70 18,7 10,50 0,64 21,5 8,24 0,54 25,3 5,18 0,42 27,3 3,52 0,34 28,9 2,20 0,24 d represents the height of the annular meniscus in the wide tube; this height will be taken into account for correcting the ascensions. In order to ascertain how far these ascensions are to be trusted, I purified a second quantity of gas, and made with it a second series of observations. t = 15,9 h = 12,78 mM. d = 0,74 mM. 20,3 9,22 0,60 22,5 7,40 0,52 24,7 5,68 0,48 26,6 4,06 0,38 28,"4 2,60 0,28 This second series agrees perfectly with the first. All ascensions lie almost exactly on a straight line, which intersects the axis of temperatures at 31,6. If therefore the ascensions continued to decrease, with rising temperature, according to a linear law, the critical point, that is the temperature at which h = 0, would be about 31,6. Direct experiments however had shown that the liquid surface vanished at 31,0. In the immediate neighbourhood of this temperature, this line must therefore be curved towards the axis of temperatures '). In order to determine where the curvature nearly begins, I made a third series of experiments in the l) The perfect agreement between these two series of observations may not yet be considered as a proof of the purity of the gas. For in both cases the process by which the pure gas has been obtained was quite the same; the two specimens were therefore necessarily of the same degree of...
