Forces between Atoms and Chemical Affinity. 767 



Radicle ON. 



Aceto-nitril, CH 3 CN 35-8 100 



Proprio-nitril, C 2 H 5 CN 27'2 102 



Benzyl cyanide, C 6 H 5 CH 2 .CN 167 109/5, where S is the density 



Ethylene cyanide, (CH 2 ) 2 (CN) 2 ... 57*3 127/5 [of the liquid. 



Radicle N0 2 . 



Nitroinethane, CH 3 N0 2 382 116 



Nitroethane, C 2 H 5 N0 2 29"5 117 



Radicle C.NS. 



Methyl rhodanide, CH 3 CNS 35'9 144/5 



Ethyl rhodanide, C 2 H 5 CNS 26*5 126/5 



Radicle CO-OH. 



Formic acid, HCOOH 57 120 



Acetic acid, CH3COOH 646 21 



Monochloracetic acid, CH 2 C1C00H 20 75 



Dichloracetic acid, CHCl 2 COOH . 8"22 38 



Trichloracetic acid, CCl 3 COOH ... 4'55 25 



In addition to the electrostatic moment due to the sepa- 

 ration of the electrical charges in the doublet itself, there 

 will, since the doublet produces an intense electric field in 

 its immediate neighbourhood, be the electrostatic moment 

 induced by this field in the other atoms of the molecule. 

 This moment will depend on the number and size of these 

 atoms, and will, unless the molecule is unsym metrical, be in 

 the direction of the moment of the exciting doublet, and 

 will be an invariable companion of this moment. Thus the 

 effective moment of the doublet may be written as P + M, 

 where M is the moment of the doublet itself, and P a 

 quantity which depends on the number and nature of the 

 other atoms in the molecules. The values of the specific 

 inductive capacity for complicated molecules show indi- 

 cations of this effect ; for example, the contribution of each 

 doublet of OH in benzol alcohol to the specific inductive 

 capacity is considerably higher than the contribution of the 

 same doublet in the simpler molecules of water and niethvl 

 alcohol. 



Another point that has to be taken into consideration is, 

 that when there are several moment- bearing radicles in the 

 molecule, the axes of these may point so that their resultant 

 is greater than that of any of the constituents, as, for 





