122 
PHYSICS: A. A. MICHELSON 
Proc. N. a. S. 
where h is Planck's constant. This numerical coincidence suggests that 
quantum phenomena may be in some way connected with rotating elec- 
tric fields, and that 
Summary. — ^The equations of electrodynamics are shown to be simple 
kinematical relations between the moving elements which constitute lines 
of force. If the sources of these moving elements are supposed to rotate, 
free magnetic charges are produced, and the four equations of the elec- 
tromagnetic field assume a symmetrical form. The energy radiated due 
to the rotation is found to amount almost exactly to V32 hv for each revolu- 
tion. 
^ The reader who is interested in following through in more detail the analysis in- 
volved in deriving these relations is referred to the author's paper on "Relativity and 
the Ether," Amer. J. Set., New Haven, 38, 1914 (169). 
In a paper of Harold Jeffreys entitled "The Viscosity of the Earth, 
the author makes use of a formula which combines the laws of Larmor and 
of Maxwell. 
The integral implies a permanent set which as the author indicates would 
be inconsistent with the "accepted theories of tidal friction and variation 
of latitude. Hence ri must be practically infinite." The formula is thus 
reduced to the expression F = ni{S T2 ds/dt). 
Experiments made on a great variety of materials show, however, that 
this expression must be seriously modified to represent the facts. 
Thus it has been shown^ that the displacement produced by a stress P 
is given by the expression^ 5 = CiPe^'^ + QP/^^ (1 — + 
CsPe^''. The last term produces permanent set, so for the present may 
be omitted. Putting 
_ 647r^2 
THE LAWS OF ELASTICO-VISCOUS FLOW. II 
By a. a. Michklson 
Rybrson Physical Laboratory, University of Chicago 
Communicated January 19, 1920 
Ci = — and C2 = — OL = - Q = i'' 
this becomes 
whence 
