Residual Valence of Various Molecules 485 



that I have not been able to find any chlorine compounds 

 which show chlorine to have a lower valence than this. It 

 might be assumed that these three valences were composed 

 of one chief and two residual valences. In that case one 

 should, of course, make the residual valence of chlor-benzene 

 6.40 instead of the value 4.40 which I have indicated. Another 

 reason why I have not counted these two valences of chlorine 

 as residual valences is that these chlorine compounds are non- 

 associating compounds, or at any rate they associate very 

 little. Hence the valences, sixteen in number, found in 

 carbon tetra-chloride are probably not free residual valences, 

 in the sense that they are valences in an active form but not 

 saturated in the molecule, but they must be saturated in the 

 molecule. On the other hand, the excess of 4.28 valences 

 found above the calculated amount may or may not be in 

 part saturated within the molecule. 



It is evident then that the determination of the residual 

 valence by this method of subtracting the theoretical number 

 from the total number found is open to these serious sources 

 of uncertainty. All that can be claimed for the method at 

 this time is that it gives a method of calculating the total 

 valences and thus estimating the residual valence, and that so 

 far as indications go in the hydrocarbons and the esters the 

 compounds are at least arranged in the order in which they 

 would be placed, judging from their reactions, if arranged 

 according to the amount of residual valence they possess. 

 I hope that methods will be found to differentiate more clearly 

 between the valences extending between the atoms and those 

 additional valences extending outward from the atoms making 

 the residual valence proper. 



It is still too early to attempt to correlate the amount 

 of residual valence with the solubility of compounds. It 

 is at least possible that in solubility other factors than the 

 number of valences come into play. The attraction between 

 the molecules of solvent and solute may involve the factors 

 which have been shown to influence cohesion, namely, molec- 

 ular weight and number of valences, as well as the amount of 



