1919.] The Siath Indian Science Congress. exiii 
immersed in the fluid” or are travelling in it. The familiar 
example in hydro-dynamics, of motion of a sphere or a cylinder 
through a frictionless fluid will occur to all. 
The hypothesis of electrons may seem to that extent to be 
a modification of the generalized statement of Lodge. But it 
appears that the mass of an electron is—partly at least—to be 
attributed to its motion, while as to the charge, nothing more 
is so far known except that it may well be associated with a 
vortical spin. . Moreover, since the electron is a constituent of 
a material atom, the mass of a material particle as well as the 
which will naturally modify speculations on these lines. 
O i dea of energy, 
may account for many outstanding problems such as the 
bright line spectra of incandescent gases ; but without entering 
into these details, it is not difficult to see that suc a theory, 
if it proves acceptable, will profoundly modify our entire con- 
ception of the processes operating in the electro-magnetic field. 
For, if we must accept the operations of finite forces in effect - 
ing changes in the field, we have to admit that we can be 
cognizant of time, only as durations and intervals, as small as 
we like, but not as the continuously flowing quantity of Newton. 
