Chemical Properties of Stannic Chloride. 485 



But the induction is based upon a fallacy. It does not 

 follow, iii the cases cited, because the densities rapidly increase, 

 relative to hydrogen, as the temperature falls, that therefore 

 the molecules have also become greater. For these molecular 

 weights are determined on the assumption that Avogadro's 

 law is applicable to these substances in a vaporized and imper- 

 fectly gasified condition. Such an assumption is untenable ; 

 it is, as Prof. J. J. Thomson emphasizes in his lectures on the 

 Properties of Matter, more rational to conceive that the va- 

 pours do not contain equal numbers of molecules. The state- 

 ments that nitrogen peroxide is " N 2 4 ," that hydrofluoric acid 

 is " H 2 F 2 ," that acetic acid is C 3 H 6 3 *, are tainted with this 

 fallacy ; and the taint vitiates the induction that leads to the 

 conception (/3) as the constitution of liquid stannic chloride. 



Moreover, positive evidence in favour of the simpler concept 

 is supplied by the simplicity of the results obtained for the 

 molecular weights of solids and liquids, as determined by the 

 extent to which they lower the fusing-points and the vapour- 

 pressure of solvents (Eaoult). 



On this ground the statement made as to the constitution 

 of gaseous stannic chloride may be extended so as to include 

 the liquid condition, provided of course a necessary degree of 

 cohesion sufficient to account for the viscosity of the liquid be 

 allowed between these simple material particles the molecules 



! 1 



SnCl 4 







an 



And, again, it may be maintained that the condition (a 

 presents a prospect of greater stability than (/3). For ai 



inspection of the graphic representation of the group | SnCl 4 | 



shows that, whereas according to (a) the chemical homogeneity 

 is preserved solely by the attractions of the respective atoms 

 of tin for their four respective atoms of chlorine, according to 

 (/3) this attraction is opposed " by the straining of the chlorine 

 atoms at the chlorine atoms of the adjoining molecules." 



Thus, then, on account of the greater stability represented 

 in the simpler view, on account of the evidence in its favour, 

 on account of the absence of satisfactory arguments to prove 

 the existence of the hypothetical complex aggregates, the 

 simpler view (a) will here be taken and the stannic chloride 

 will be considered as strictly homogeneous; sic cegualiter for 

 the other-mentioned nonconductors. And it is advanced that 

 every substance thus strictly homogeneous is a nonelectrolyte 

 on account of that very homogeneity. This homogeneity is a 



* Horstmami, Annalen, clxviii. VI. sup. 53. 

 Phil. Mag. S. 5. Vol. 29. No. 181. June 1890. 2 P 



