ee 
ON ELECTROLYSIS. 759 
These things appear in a great many of his writings, first in his great 
Memoir of 1847, but they are conveniently summarised in his Faraday 
Lecture of 1881, from which I have just now been quoting. 
It is scarcely decent to obtrude my own opinion on so fundamental a 
subject as this, but I may be permitted to say that if one does grant such 
an attraction, and if one further conceives positive and negative electricity 
as the two coustituents of ether, not only chemical affinity but specific 
inductive capacity and refractive index, together with the Fresnel-Fizeau 
connection between ether and matter, can be readily conceived and, so to 
speak, accounted for; and the attraction of gravitation does not lag far in 
the background. Seven years ago I spent some time endeavouring to set 
out all these things in a systematic and pretentious form, but I came to 
the conclusion that the task was beyond my strength. The special 
things which Helmholtz more particularly explains by his theory—viz. 
contact E.M.F., thermo-electricity, and frictional electricity—did not 
suggest themselves to me in sucha direct connection with it; nor do they 
now. 
The theory of Helmholtz insensibly impels one to try to apply ordinary 
electrostatic considerations to the interactions of atoms and to the effect 
of electrodes upon them. It suggests, in fact, a theory of chemistry ; in 
the form of a sort of supplementary kinetic theory of gases with electrified 
atoms. But the liquid state, which (more than ever by recent researches!) 
seems essential to chemical action, has difficulties of its own to be over- 
come before the behaviour of electrified atoms can be properly treated. 
It may be noted that whereas the actual force of attraction between 
two atoms at a distance like 10~° is not great, being something like 10~* 
dyne, the acceleration produced by it in the smal! mass of an atom is 
terrific, being nearly a trillion times that produced in ordinary bodies by 
the earth. To show that mechanical forces are insignificant compared 
with electric ones between charged atoms, Helmholtz reminds us that 
their electric attraction at any distance exceeds their gravitative attrac- 
tion at the same distance nearly a hexillion times.” 
1 Those of Mr. Dixon and others on combustion and on gaseous combination or 
explosion. As Professor Armstrong has pointed out, they seem to suggest a necessity 
for the presence of a dissociated typical compound, i.e. for electrically charged atoms 
(see above), in every reaction. Should this turn out to be a fact, it will be one of 
profound chemical and physical interest. 
2 This is not exactly Helmholtz’s way of putting it (Faraday Lecture, 1881), but 
it comes to the same thing; and it is perhaps as well to notice that there is nothing 
uncertain about the calculation: the least accurately known datum in it is the 
gravitation constant, or the earth’s mean density. The general expression for the 
ratio between the electric attraction of two radicles in an electrolytic compound and 
their gravitative attraction, at any given distance, is 
v2 
AY My Hon?” 
where V is the velocity of light, » the electro-chemical equivalent of hydrogen, ¥ is 
the gravitation constant, gR*/E, or , While uw, and w, are the combining equi- 
39 
8p x 10° 
valents of the radicles in the compound compared with hydrogen; or u, +p, is the 
compound’s ordinary ‘ molecular weight’ divided by its ‘atomicity ’: e.g. for water, 
#, #2=8; for copper sulphate, 80; for silver nitrate, 6696. 
The numerical value of the above ratio is 
TD sS 
Bey Me 
