the Shape of the Molecule. 447 



^4.Q'7 

 temperature ^~^- T c was calculated from the formulae given 

 55b'l 



in Landolt and Bernstein's Tables, 5th edition. The mole- 

 cular volume Y is proportional to / — J Column 8 contains 



the relative values of *—l- or — , the ratio of the axis of 

 m a 1 



the circular section of the spheroid to the axis at right angles 



to the section. 



Table I. 



Name of Substance. 



Abs. 



Temp. 



T. 



P- 



?;X10 T 



m 

 p' 



(wT) 1 4 



Relative 

 values of 

 m 



2 01 * 



<T 8 . 



Relative 

 values of 



— i- or 



m 



<r 2 



( 2 ™V3yV2 

 or^. 



^/ 2 xio 7 / 2 



or relative 

 values of 



Carbon tetrachloride ] 

 C01 4 j 



Ethyl oxide... C 4 H 10 O 



Benzene OyHy 



Methyl formate 1 



C 2 H 4 2 \ 



Ethyl propionate 1 



O 5 H 10 O 2 f 



Chloroform... CHC1 3 



3497 



293-9 



353-1 



306-2 



343 



335-2 



1-5030 

 •7123 

 •8145 

 •9553 

 •8308 



1-3935 



1950 



745-2 

 1057 



997-9 

 1074 

 1905 



1024 

 103-9 

 95-76 



62-82 

 122-7 



85-78 



•3449 



•4448 



•3962 



•3686 r 



•4173 



•3242 



6839 

 524-9 

 6101 

 462-3 



705-2 

 816-2 



5-044 

 8-474 

 6-494 

 7*975 

 5-917 

 3972 



2-22 

 361 

 3-28 

 3-76 

 3-86 

 2-66 



It will be seen that the values of this ratio are by no 

 means constant, showing that the shape of the molecule is 

 far from being spherical. 



The absolute value of the ratio — for a molecule cannot 



be calculated, because we do not know the absolute molecular 

 volume of a molecule. But this ratio can be approximately 

 obtained as follows. The writer has shown * that the diameter 

 of an atom is proportional to m 1/6 , and its cross-section there- 

 fore proportional to m 1/3 . The cross-section of the molecule 

 coinciding with the plane in which the atoms lie will there- 

 fo re be %m 1/s , and its radius is therefore proportional to 

 A^Xm 11 ' 3 . Now the volume of the molecule according to 

 Traube is proportional to 2m 1/2 , and the length of the axis at 



2m 1/2 

 right angles to the circular section is therefore ^ — =-=?, The 



/^ m i/3\3/2 2m 1 / 3 



ratio of the two axes is then --^- , -. - . 



The values of this ratio have been calculated and are given 

 in the 9th column of Table I. It will be seen that they bear 



* Loc. cit. 



