1919.] The Sixth Indian Science Congress. exvil 
reference to them. If one of these frames of reference be 
situated in the ethereal medium, supposed to be the same as 
the electromagnetic field, this apparently leads to the conclu- 
sion that the ether may be supposed to be moving with any 
arbitrary velocity, whatsoever. 
Now various lines of arguments seem already to point to 
the conclusion that the electro-magnetic field, if identified with 
an e 1 medium cannot be held altogether to be either 
inert or immobile. There is the intrinsic (kinetic) energy of 
the field to be accounted for, as well as the property of the 
medium as a carrier of momentum of radiation. And as to 
4 
oe 
a) 
fae) 
bs 
= 
5 
a 
5 
5 
n 
@ 
5 
— 
oO 
bar | 
2) 
° 
a 
5. Qu 
2 
5 
=} 
or 
a 
eed 
tA 
5 
et 
° 
2 
= 
ro) 
= 
= 
ia?) 
B 
re 
7 
. 
c 
cal discussion of all physical measurements, a careful study of 
the exact meaning of continuity of functions, of limit, of infinity, 
have removed much vagueness and want of precision that 
previously obtained. The theory of Fouriers series, for instance, 
in its original form and much subsequent applications took, as 
we know, much for granted. An enquiry has been successfully 
instituted in recent times as to the extent to which these 
assumptions are valid, and this has led to a clear understand- 
ing of a function of a real variable, of convergency and of 
deal with similar functions in three or four dimensions, we 
may well look for important generalisations of the theory 
from the point of view of modern physics. ae 
Again it may be well to remember that application of 
