96 Mr. J. Kam on Molecular Attraction and 



Table V. 





pi. 



16 



14 

 14 

 15 



41-45 

 20 

 2 



1 

 8 



Tc 



\v c . 



I . M 2 . 3 . 10 - 6 = c = ii' C {T c /273} 2 . 



0, 



155 



127 



131-9 



179-5 



210-5 



•00213 



•002585 



•0025 



•001735 



•002fifi 



7-68 . 10- 4 

 5-88 . 10~ 4 

 5-88 . 10--» 

 6-75 . 10~ 4 

 5-15 . 10~ 3 

 1-20 . 10- 3 

 1-20 . 10- 6 

 300 . 10- 6 

 1-92 . 10--* 



690 . 10 ~ 4 

 5-60 . 10 -4 

 584 . 10~ 4 

 7-50 . 10" 4 

 1-65 . 10" 3 

 0-66 . 10 * 3 

 0-50 . 10 ~ 6 

 2 694. 10" 5 

 1032 . 10~ 4 



N, 



CO 



NO 



Kr 



A 



155-6 i 00202 

 5 -001495 

 39 -00132 



He 



H, 



0H 4 



177-5 



•00244 



If the actual molecular weight is different from the one 

 adopted, then large deviations may be expected from the 

 expressions (46) and (48) and in some cases (42). Thus 

 water only satisfies equation (42) i£ at the critical state 

 it consists of equal numbers of molecules [H 2 0] 3 and [H 2 0] 4 . 

 (Vernon assumes for water the formula [H 0]4, Chem. News, 

 lxvi. p. 54, 1891.) 



A substance following the rule 2p c . v c = const, can hardly 

 during the experiment dissociate or polymerize. But if it 

 deviates from this rule, it need not do so from the rule of 

 equation (42), as l/v c and M would be equally affected, and 

 any change in the number of molecules would alter M in the 

 opposite sense. This would of course not be so in the case 

 of equation (48). 



The material is, however, too large to allow of detailed 

 discussion, and 1 only wish to point out how the compliance, 

 or non-compliance with the preceding rules can assist us in 

 forming an idea with regard to association or dissociation of 

 molecules during the experiment and the molecular weight. 



If the cohesive forces account partly for the deviations of 

 the gaseous laws, by opposing the thermic pressure and 

 expansion, they must also cause resistance against pull 

 in the case of solids or liquids. In some solids the number 

 of molecules (atoms) is so great that translatory velocity 

 seems hardly possible, especially in crystalline structures. 

 Association of molecules would in itself not necessarily 



increase the inward pressure />i = — 2 = c . N 2 . m 2 , as N de- 

 creases as m increases. But the number of molecules, the 

 number of impacts, i. e. the thermic pressure decreases. 



