
the Charges on Ions. 279 
numbers, since there is strong evidence to show that the 
differences must be due to experimental errors. The value 
of N xe thus obtained is 
Nx e= F933 107", 
e being the charge on an ion in a gas. 
It has been pointed out that Nx E=1:22 10— where I 
is the charge on a hydrogen ion in a liquid electrolyte; and 
hence we see that the charges on ions in gases produced by 
various methods are equal to the charge on a hydrogen ion 
in a liquid electrolyte. This result depends only on the 
value of the product N xe, and it is not necessary to rely on 
the determinations which have been made of these quantities 
separately in order to obtain a proof of the proposition. 
The determinations which have been made of N and e 
vary over considerable ranges, and what are considered to 
be the most probable values of these quantities do not give 
the product N x e=1:23 x 10". If one of the quantities could 
be determined the other would follow, since the product is 
known accurately; but it is difficult to decide which has 
been found with the greater accuracy, as in both cases there 
are weak points in the assumptions which are made, and in 
addition there is considerable experimental error in the de- 
termination of the charge ec. Nevertheless, it is not unsatis- 
factory to find that the product only differs by a factor of 
about 3 from the number 1°23 x 10. 
Lord Kelvin* has recently passed in review the various 
methods which have been employed to determine Nf, the 
number of molecules in a cubic centimetre of a gas at 0° C. 
and standard atmospheric pressure. 
From the calculations he has made it seems more probable 
that 10°° is nearer to the true value of N than 8-9 x 10", and 
it is not improbable that the true value is greater than 10°’. 
This number is deduced from the coefficient of viscosity of 
argon and from its densities in the liquid and gaseous states. 
Using the formula NE=1-22 10, it is seen that 1°22 10—!° 
is not improbably an upper limit to the values of the charge 
in electrostatic units. 
The following are the values of e found experimentally by 
different observers :— 
* Lord Kelvin, Phil. Mag. August & September 1902. 
+ This number is about 5 per cent. greater than the value of N with 
which we have been dealing, which refers to 15° C. and standard 
atmospheric pressure. 
