262 
THOMPSON YATES LABORATORIES REPORT 
From these figures of Tereg's, and preferably from the value obtained of the 
resistance at 2I°C, a value can be calculated for the so-called 'specific resistance.' 
Specific resistance ... ... = R x cross section x 
7T r 2 
= 700 X — -7— 
(•6) 2 x 3-14 
= 700 x — T 
3-45 
I'll 
= 700 X ? 
3-45 
= 230 ohms approx. 
The specific conductivity in terms of mercury therefore is (for data see previous 
example) — 
95-4 x io- 6 
230 
41 X I o~ 
A value which an examination of the table of specific conductivities of solutions 
of sodium chloride will shew is approximately the same as such a solution of the 
strength of "3 grammes per cent. The figures given by Tereg, therefore, closely 
agree with those found from the previous experiments, and like them set the electrical 
conductivity down at a very low value. 
The modifications with temperature, as observed by him, are also of con- 
siderable interest, since they show this agency affecting the values in a quantitative 
manner, exactly agreeing with that known to occur with change of temperature in 
solutions of electrolytes. 
Thus the conductivity at 2 1° C. is ~, at 45 0 C. it is 4- o . The alteration thus con- 
sequent upon a rise of temperature through twenty-four degrees is ~ — ~ or 
Treating this latter figure as a fraction of the original conductivity of it is seen to 
represent a rise in the original value of almost exactly fifty per cent., or two per cent, 
per degree of temperature. 
The value of such a result is considerable, as is seen from a reference to the 
following quotation : ' The molecular conductivity of a given electrolyte depends in 
the first instance on the temperature, increasing almost without exception with rise of 
temperature, and mostly by about 2 per cent, per degree.' 1 
The nerve, owing, as has been previously stated, all its electromotive phenomena, 
inclusive of electrical conductivity, to the solutions of electrolytes contained in it, is 
seen from the point of view of this modification with temperature to behave like 
any solution of electrolytes. This is a fact worthy of consideration when, as has 
sometimes been attempted, assumptions are made as to the mobility of the particles 
contained in it with the conduction of an electrical current other than that of the 
motion of ions in solution. 
1. Outlines of General Chemistry, Ostwald, translated by J. Walker, London, 1895, p. 276. 
