being such that a=— -3, and the gas B in excess. Examples of such reactions are 2H2+0,2H2O oxygen in excess. Now let the volume-change, when neither reactant is in excess, be given by These numbers give the curves in fig. 2. The curves are applicable to all ter-molecular gas-reactions of the type 2A+B at constant pressure when the volume-change is is 2NO+O, NO, oxygen in excess. Reactions with A in excess. Such a reaction Let us reconsider these reactions in which aand a=- when the A gas is in excess. Take first a=-1. Equation (4) becomes The curves obtained from these numbers are given in fig. 3. = 0 (p−X)3(1−X) 1 S_2p-1 p-x 1 X log. 1+2p (p-1) (1-X) p(p-1) p-XS' For p=1. ..... 0 2 4 5 6 7 8 9 1-0 0 261 751 1.167 1.874 3.235 10.666 22:50 00 These numbers are plotted in fig. 4. Curves for reactions in which a has other values can easily be worked out from equations (3) and (4). Values of a other than - are uncommon. When the resultants of the reaction are solid or liquid, a= −1. General Curves for Reactions of Higher Orders. 0 5 1.0 15 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6-0 examples have not been worked out. General curves for any particular type of reaction can be obtained by following a procedure similar to that used in this paper. London, February, 1918. THIS LII. Notices respecting New Books. Annuaire du Bureau des Longitudes pour l'année 1918. Pp. viii+869. Paris: Gauthier-Villars. Price 2 francs. HIS excellent almanack contains, in addition to the usual astronomical data, many other tables of interest relating to meteorology, terrestrial magnetism, and kindred subjects, together with a very useful collection of physical constants. Besides the tables there are special articles, written by good authorities, on the following subjects: Sundials, the Egyptian Calendar, Time at Sea, the Sun and Terrestrial Magnetism, and an obituary notice on Professor Gaston Darboux by M. Picard. The book is embellished with star maps and figures, and is a very useful and wonderfully cheap publication, |