J. H. Jeans, Nature, vol. 115, p. 364, 1925. 
THE QUANTUM 
condition of physics. . . . We find it hard to rest content with 
the existence of unrelated absolute constants, such as Planck’s 
constant and the size of an electron, which, so far as we can see, 
might just as easily have had any different magnitude. To the 
scientific mind such facts are a challenge, leading to a search for 
some way of inter-relating them and making them seem less 
accidental.” 
The possibility of establishing a relationship between Planck’s 
constant, h, and the electron charge, e, was suggested in 1911 by 
Einstein, who pointed out that the product he (where c is the 
velocity of light) has the same physical dimensions as the square 
of an electric charge, when the charge is measured in electro 
static units. Jeans commented on this at the Birmingham 
meeting of the British Association in 1913, and in the first 
edition of his Physical Society Report on Radiation and the 
Quantum Theory (1914) wrote: “In point of fact, hc/2n, if 
not exactly equal, is almost equal to (4ne) 2 , i.e. to the square 
of the strength of a tube of force binding two electrons. This 
suggests that the atomicity of h may be associated with the 
atomicity of e.” 
Various attempts have been made to establish a relation 
between he and e 2 , and the more important of these will be 
discussed in the present chapter, although it may be said at the 
outset that no final and entirely satisfactory solution has yet 
been reached. The problem may be attacked in two ways, 
either by endeavouring to find an exact numerical relation 
between the quantities involved, or by finding some hypothesis 
of a physical nature which may serve to link together the two 
types of atomicity. 
Jeans * has given an illuminating account of the nature of 
the atomicity demanded by the theory of electrons and by the 
quantum theory. 
“ Electric charges are a consequence of, or at least are 
associated with, a curving or crumpling of space, but so far as 
pure geometry goes there is no restriction on the extent of this 
crumpling, so that our geometer, reasoning from geometry alone, 
might expect to find charges of all possible amounts, whereas in 
actual fact electric charges occur only in multiples of a definite 
unit, the charge of an electron. It is clear, then, that there 
is something more than geometry underlying the phenomena 
of Nature; the whole phenomenal universe may be geometry 
with restrictions if we like, but not merely the geometry 
which is obtained by generalizing the geometry of Euclid 
until we can generalize no further. Space can be crumpled up