262 Canadian Record of Science. 



analysis and from vapor-density, has been long maintained 

 alike on dynamical and chemical grounds. It is discussed 

 by the writer in 1853 in the essay already quoted, entitled 

 "The Theory of Chemical Changes and Equivalent Vol- 

 umes," l and again in the late paper of Spencer Pickering 

 in the Chemical News for November, 1885. 



If, then, as maintained by the writer, the law of volumes 

 is universal, and if the production of liquids and solids by 

 the condensation of vapors is a process of chemical union, 

 giving rise to polymerids, the equivalent weights of which 

 are as much more elevated as their densities are greater 

 than those of the vapors which combine to form them, the 

 hypothesis of atoms and molecules, as applied to explain 

 the law of definite proportions and the chemical process, is 

 not only unnecessary, but misleading. According to this 

 hypothesis, which supposes molecules to be built up of 

 atoms, and masses of molecules, the different ratios in 

 unlike species between the combining weight of the chemi- 

 cal unit or molecule (as deduced from analysis and from 

 vapor-density ; H = 1.0) and the specific gravity of the 

 mass are supposed to represent the relative dimensions of 

 the molecule. Hence, the values got by dividing these 

 combined weights by the specific gravity have been called 

 " molecular volumes." The number of such molecules 

 required to build up a physical molecule of constant volume 

 would, according to this hypothesis, be inversely as their 

 size. If, however, as all the phenomena of chemistiy show, 

 the formation of higher and more complex species is by con- 

 densation, or, in other words, by identification of volume, 

 and not by juxtaposition, it follows that the so-called mole- 

 cular volumes are really the numbers representing the rela- 

 tive amount of contraction of the respective substances in 

 passing from the gaseous to the liquid or solid state, and 

 are the reciprocals of the coefficient of condensation of the 

 assumed chemical units. If steam at 100° C. and 760 milli- 

 metres pressure, with a formula, as deduced from its density, 

 of H 2 0, and a combining weight of 18, is converted into 



1 See the author's " Chemical and Geological Essays," pp. 426-437, 

 and, further, ibid., pp. 453-458. 



