582 



DR MAGVICAR ON THE LAW OF VOLUMES OF AERIFORMS 



The icosahedron, 

 The dodecahedron, 

 The octohedron, 

 The hexahedron, 

 The tetrahedron, 



20 trigonal elements, 

 12 pentagonal elements, 

 8 trigonal elements, 

 6 square elements, 

 4 trigonal elements. 



y or facets. 



But it is with the more perfect, the two first named, almost exclusively, that 

 we shall have to do when treating of the primary molecules of bodies. When, 

 indeed, the elements forming into molecules are very volatile, then, instead of 

 the icosahedron (or icosatom), which is the form of culmination, but which 

 demands the simultaneous concurrence of 20 elements to construct one molecule, 

 we have the octohedron and tetrahedron, whose elements are the same as those of 

 the icosahedron, but which demand the concurrence of only 8 or 4. As to the 

 hexahedron, its sphere of development is not among the primary molecules of 

 bodies, but among those highly composite molecules, where crystallisation 

 begins. 



It must be added also, that the cosmical element of aq or HO, which is here 

 (as is usual) taken as unity for specific gravities, is assumed to be (as indeed 

 aq and HO indicate) dimorphous; as is also its molecule of culmination, or 

 that which constitutes a particle (or unit-volume) of water ; the architectural 

 element of the latter, when it adopts the form of one of the regular polyhedra 

 (the dodecahedron), being not one but three atoms of HO. In other words, our 

 unit-volume of water consists of 36 atoms of steam or vapour, while most other 

 substances consist of 12 only, or 20 at the most. Hence, our constant divisor for 

 specific gravities is aq..^^, which we may write AQ, and whose weight on the hydro- 

 gen scale is therefore 9 x 36 = 324.* 



Adopting the letter X, then, to represent any chemical unit whatever, and Y 

 and Z to represent dissimilar units, we immediately obtain as the molecules of 

 dense bodies Xg^ and X^^, and occasionally, among volatile substances, Xg and X^. 



But here the grand law of chemistry, the law of differentiation, presents 

 itself to our regard. Dissimilars only unite chemically ; and the condition of 

 molecular stability or repose in the interior of a mass or medium is, that it be duly 

 differentiated internally. Hence, given X as material for molecular constructions, 

 we shall not only have X20 or X^.^, but as often as possible, and that in the same 



* That an unit-volume or particle of water consists of three times the number of chemical units 

 or elements or minims, which other molecules in general consist of, is shown by the numbers of aeri- 

 form volumes which it and they respectively give. Thus, a volume of cold water gives from 1700 to 

 1728 volumes of steam, according to estimate, of which the third part is from 567 to 576. A 

 volume of alcohol, when its vapour is heated up to the temperature of steam, gives 570 volumes. A 

 volume of ether, supposing its aeriform units of volume to be dedoubled so as to assimilate it to 

 water and alcohol, gives, at the same temperature, 2 x 285"9 = 572 volumes And so in other cases, 

 where at first sight there seems no relation. Thus, oil of turpentine gives, of the same tempera- 

 ture, only 193 volumes. But the formula of the unit of that liquid is C2oHjg = 4(C.H^). It 

 requires, therefore, to be multiplied by 3 to bring it up to the dodecatom, and render its vapour- 

 volume comparable with the others. Now, 3 x 193 = 679, near enough the others. Good experi- 

 ments in this field would be verv valuable. 



