The electron, its isolation and measurement and the determination of some of its properties — John Stuart Mill — John Shaqi
The electron, its isolation and measurement and the determination of some of its properties
John Stuart Mill · en
It is practically this identical point of view which has been
elaborated and generalized by Lorentz and others within the past three
decades in the development of the modern electron theory, with this
single difference, that we now have experimental proof that it is the
negative particle whose mass or inertia is negligible in comparison
with that of the positive instead of the reverse. Weber even went so
far as to explain thermo-electric and Peltier effects by differences
in the kinetic energies in different conductors of the electrical
particles.[5] Nevertheless his explanations are here widely at variance
with our modern conceptions of heat.
Again, in a paper read before the British Association at Belfast in
1874, G. Johnstone Stoney not only stated clearly the atomic theory
of electricity, but actually went so far as to estimate the value of
the elementary electrical charge, and he obtained a value which was
about as reliable as any which had been found until within quite recent
years. He got, as will be more fully explained in the next chapter,
, and he got this result
from the amount of electricity necessary to separate from a solution
one gram of hydrogen, combined with kinetic theory estimates as to the
number of atoms of hydrogen in two grams, i.e., in one gram molecule
[Pg 22]
of that element. This paper was entitled, “On the Physical Units of
Nature,” and though read in 1874 it was not published in full until
1881.[6] After showing that all physical measurements may be expressed
in terms of three fundamental units, he asserts that it would be
possible to replace our present purely arbitrary units (the centimeter,
the gram, and the second) by three natural units, namely, the velocity
of light, the coefficient of gravitation, and the elementary electrical
charge. With respect to the last he says:
Finally nature presents us with a single definite quantity of
electricity which is independent of the particular bodies acted on.
To make this clear, I shall express Faraday’s law in the following
terms, which, as I shall show, will give it precision, viz.: For
each chemical bond which is ruptured within an electrolyte a certain
quantity of electricity traverses the electrolyte which is the same
in all cases. This definite quantity of electricity I shall call
. If we make this our unit of electricity, we shall probably
have made a very important step in our study of molecular phenomena.
Hence we have very good reason to suppose that in ,
and , we have three of a series of systematic units that in
an eminent sense are the units of nature, and stand in an intimate
relation with the work which goes on in her mighty laboratory.
Take one more illustration from prominent writers of this period.
In his Faraday lecture delivered at the Royal Institution in 1881,
Helmholtz spoke as follows: