234 Scientific Intelligence. 



movements of the atoms in relation to each other, rather than on 

 the relative positions of the atoms in space, which is the funda- 

 mental hypothesis of " stereochemistry." The new view regards 

 the bonds by which the union of atoms is customarily represented, 

 as signifying the nature of the swing of the atoms with relation 

 to each other, i. e., their energy. Tims doubly linked and singly 

 liuked carbon atoms are of different value in respect to the energy 

 of their movement with regard to each other, and double or treble 

 bonds signify excess of energy, ready to be exerted in saturating 

 the compound. This hypothesis the author applies to the benzene 

 ring and shows that only one ortho-bi-substitution product is pos- 

 sible. Motoisomerism involves asymmetry but the terra must be 

 used in a greatly extended sense, the phenomenon depending on 

 the mass and valence of the atoms or atomic groups as well as on 

 their number and nature. Moioisomerides will exist in those 

 cases in which it is possible for the order of approach of the asym- 

 metrical carbon atom (taken in this sense) to vary toward the 

 neighboring atoms. In the case of benzil-monoxime 



COPh.C = ^ OH 



for example, it is possible for two motoisomerides to exist ; for if 

 the swing between carbon and carbon be designated by a and 

 that between carbon and nitrogen by b, these isomerides will be 

 represented (1) by a, a, b, b, and (2) by a, b, a, b. — J. prak. 

 Chemie, II, xlviii, 113 ; J. Chem. Soc., xliv, ii, 513, Nov. 1893. 



G. F. B. 



6. On the Densities of Oxygen, Hydrogen and Nitrogen. — The 

 densities of oxygen, hydrogen and nitrogen have been determined 

 with great care by Lord Rayleigh. The oxygen was prepared 

 by three different methods : (1) from chlorates, (2) from potas- 

 sium permanganate and (3) by electrolysis. The air was taken 

 from outside and was passed through potash solution, then 

 through tubes filled with fragments of solid potash and finally 

 over phosphoric oxide. The nitrogen was prepared by passing 

 air through a potash solution, over reduced copper, then through 

 a U-tube to deposit water again over heated copper and finally 

 over heated copper oxide. The values of the densities of oxygen, 

 nitrogen and hydrogen respectively, as compared with those 

 obtained by other experiments, all referred to that of air as unity 

 are given in the following table : 



Oxygen. Nitrogen. Hydrogen. 



Regnault (corr.) 1-10562 0-97138 0-06949 



v. Jolly (corr.) 1-10502 0-97245 



Leduc 1-1050 0-9720 0-06947 



Rayleigh 1-10535 0-97209 0-06960 



Mean... 1-10525 0-97218 0-06952 



