'238 RELATION OF PHYSICAL PROPERTIES OF AQUEOUS SOLUTIONS 



A glance at these tables shows that if regard be had to sign, 

 Grotrian's conclusion as to the temperature-coefficients for con- 

 ductivity and fluidity applies to all the coefficients for all the 

 properties tested. A given change in the concentration pro- 

 duces a change in the coefficients in the same sense. Too much 

 importance, however, must not be attached to this ; for it is 

 obvious that if we should tabulate, say, the coefficients for con- 

 ductivity, surface tension, viscosity (instead of fluidity) and 

 specific volume (instead of density), it would be found that the 

 changes produced in the first two are in the opposite sense to 

 those produced in the last two. It is interesting, however, to 

 note that the expectation suggested by the above formulse is 

 distinctly realized. 



At very great dilution of electrolytes, the temperature-coeffi- 

 cient becomes, approximately, 



~P~W = (~6t + n ~6i'' w+> 



the pressure-coefficient having the same form. The concentra- 

 tion-coefficient becomes 



1 (JP 



^ , ,w*i . , (10) 



P on 



If we compare (9) and (10) with (7) and (8), it becomes 

 obvious that the variation with concentration of the tempera- 

 ture arid pressure coefficients will probably be more closely 

 related at low than at high concentrations, but that the oppo- 

 site will be true of the concentration coefficients. Accordingly, 

 having plotted Grotian's coefficients and those of the above tables 

 as functions of the concentration, I find that the temperature 

 coefficient curves, for any one substance in solution, are in 

 general more closely similar at low than at high concentrations ; 

 but that this is not the case for the concentration coefficient 

 curves. In the case of the pressure coefficients the data are 

 insufficient. 



A corresponding similarity holds for the absorption spectra 

 of solutions though it cannot be expressed in coefficients. In a 

 former paper * I have shewn that for all solutions for which 



* Trans. Roy. Soc. Can., ix (1891), sec. 3, p. 27. 



