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MR. W. R. BOUSFIELD: IONIC SIZE IN RELATION TO 
into water would depend upon the number and size of the molecules so introduced. 
According to the theory postulated, an ion is a compound molecule consisting of the 
ionic nucleus with its envelope of water molecules, as are also the un-ionised molecules 
of the solute. Hence, if the theory be true, we should expect to find a close relation 
between the viscosity of the solution and the number and size of these aggregates. 
The number of molecules depends upon the concentration m, and the size upon the 
radions ; the product m(r 1 + r 2 ) should therefore be a measure of the joint effect of the 
introduced ions upon the viscosity in dilute solutions. 
In the following tables are set out the concentrations, the sums of the radions, the 
products m (r y + r 2 ) and the observed and calculated viscosities for KC1 and NaCl. 
In Diagrams VI. and VII. the viscosities are set out as ordinates upon the products 
m(r 1 + r 2 ) as abscissae. It will be seen that the viscosity is approximately a linear 
function of m(r l + r 2 ), the expressions being 
for KC1 . . . rj = 0-010514-0-00578 m(r 1 + r 2 ) . . . (14), 
for NaCl . . . t) = 0'010514 + 0’0272 m(n+r,) .... (15). 
