386 Scientific Intelligence. 



that by supposing the haloid elements to be trivalent, the molecu- 

 lar compounds of their salts can be better explained than is possi- 

 ble if the atoms are grouped about a central atom of high 

 valence. The author thinks that the properties of the peroxides 

 Ba0 2 and Mn0 9 , which are quite distinct from those of Si0 2 and 

 Sn0 2 , point to a formula R"=z:0=:0, and thus sustain the quad- 

 rivalence theory. The same is true of the oxides of silver, mer- 

 cury and copper. As sodium dioxide is not decomposed by heat, 

 he supposes it to have the structure Na— O — O — Na; although 

 in K 2 4 he assumes an oxygen nucleus (0 4 )" analogous to that 

 in KC10 4 and C1 2 4 . Moreover, this view that oxygen may act 

 as a tetrad, at least occasionally, is supported by the interaction 

 of water with various organic substances such as aldehyde, acetal 

 and acetic acid, by Ramsay and Young's gaseous acetic acid 

 molecule C 4 H 8 4 and by the substance (CH 3 ) 2 0HC1, described 

 by Friedel. The same is true of the double metallic oxides, basic 

 salts, and water of crystallization ( — OH 2 .OH Q .OH 2 — ). The 

 author proposes the term validity, in cases where the same atom 

 has two valences, to indicate the less powerful attraction ; so 

 that chlorine would be univalent and trivalid, carbon is quadriva- 

 lent except in CO and CNO where it is bivalid. As J. J. Thom- 

 sen has shown, according to the vortex theory a dyad may unite 

 not only with two but also with four monad atoms ; so that 

 water may consist of three primaries H 2 — O— O. With this con- 

 clusion the author's formula H 2 = = evidently agrees. It 



agrees also with Brodie's H 2 00. — Phil. Mag., Y, xxv, 221. 



G. F. B. 



6. On the Carbon Atom and Valence. — V. Meter and Riecke 

 have pointed out that the theoretical conclusions of Yan't HofF 

 and Wislicenus, supported and extended as they have been by 

 the experiments of Meyer and others on the isomeric benzil-diox- 

 imes, require a modification in the generally accepted theory of 

 the carbon atom and necessitate the addition to it of the two fol- 

 lowing properties: (l) The four valences of the carbon atom 

 can be diverted from the regular tetrahedric direction in which 

 they are supposed to exist in marsh gas and compounds of the 

 constitution C<x 4 ; and (2) There are two ways in which two 

 singly bound carbon-atoms can be united, one which allows free 

 rotation in various directions, and one which does not. On vari- 

 ous chemical and physical grounds, the authors offer the follow- 

 ing hypothesis on the constitution of the carbon-atom : The 

 carbon-atom is surrounded by an setherial shell which in the 

 case of an isolated atom, has a spherical form ; the atom itself 

 is the carrier of the specific affinities, the surface of the shell is 

 the seat of the valences; each affinity is determined by the 

 existence of two opposite electrical poles which are situated at 

 the end-points of a straight line small in comparison with the 

 diameter of the sethereal shell. Such a system of two electric 

 poles is called a double or di-pole. The four valences of a carbon 

 atom would be represented by four such di-poles, the middle 



