144 



Mr. W. Sutherland. 



[July 26, 



different temperatures. Hence, our equation (3) expresses both this 

 dependence of MA/C on the viscosity of water and on velocity inside the 

 globulin compound. Thus the present theory of colloids is able to give a 

 consistent account of these important features of the chemistry of globulin. 

 The precipitations of globulin hardly need review in this connection, as they 

 have been pretty fully considered in Section 3. 



5. The Electric Conductivity of Globulin Solutions. 



Hardy, by overcoming the experimental difficulties of measuring these 

 conductivities, has obtained data of great importance, which I propose 

 to make more available by expressing them in interpretable formulae. With 

 HC1 1 gramme of globulin was dissolved in 932 x 10 -5 gramme equivalents of 

 acid, and the solutions prepared from this by successive dilution have their 

 strengths given by v, the volume of solution containing 1 gramme equivalent 

 of HC1. From the measured specific conductivity of these solutions the 

 molecular conductivity of the HC1 is calculated in the usual way, but it 

 should be noticed that it is expressed with reference to a unit of resistance 

 10 times as large as that often used, so that conductivities are made 

 10 times as large. Tor HC1 globulin solutions the molecular conductivity /j, 

 of the HC1 given by Hardy* is expressed by — 



1/fjL = 0-00026 -f- 0-009^, (14> 



as the following comparison shows : — 



Table VI. 



jx calc 

 jx exp, 



107 



217 



434 



868 



1735 



3470 



465 



568 



690 



830 



991 



1170 



439 



596 



706 



834 



991 



1167 



At infinite dilution (14) gives //, = 3846, the value for pure HC1 being 

 3840. It appears, then, that at infinite dilution HC1 globulin is entirely 

 dissociated, yielding completely ionised HC1. The equation having so 

 extensive a range must have fundamental theoretical significance, which is 

 easily brought out. The occurrence of v~* reminds us of Kohlrausch's 

 discovery that the molecular conductivity of dilute electrolytic solutions is 

 a linear function of v~*, a fact which I have sought to trace back to the 

 3 occurring in the formula (H 2 0) 3 for trihydroLf 



For the molecular conductivity of an ion of radius a, valency v, dielectric 



* Loc. cit, p. 274. 



+ See "The Molecular Constitution of Water," and " Ionisation, Ionic Velocities, and 

 Atomic Sizes," ' Phil. Mag./ [5], vol. 50, and [6], vol. 3. 



