196 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 10 
in all matter and energy—the five dimensions in which the universe 
as at present known to us could then be described would be (Ii) 
x (Ly) X (L3) X (T) x (P). It may be possible in the future to write 
(P) in terms of space and time. Indeed it may possibly be nothing 
else than time, since, as has been generally recognized, time has a 
definite psychical element in it. 
Leaving the dimensions of P at one side, the object of the present 
paper is to show how all the physical phenomena of the world may be 
expressed in dimensions of space and time to the great simplification 
and clarification of many conceptions. 
Several attempts to do this have been made already with more or less 
success. Sir Oliver Lodge,? for example, has pointed out that the 
2 Lodge: Modern Views of Electricity, 1889, Macmillan & Co. Appendix, page 402. 
“Comparing many electrical equations with corresponding mechanical ones we find 
that the product LC (L being length and C current) takes the place of momentum(mv) 
and that 1/2 LC? takes the place of kinetic energy (1/2 mv?) and indeed is the energy of 
a current. Hence it is natural to think of L as involving inertia and of » and 47 was a 
kind of density of the medium concerned. Assuming this 4 7/K at once becomes an 
elasticity coefficient (as indeed electrostatics suggests) because »Kv? = 1; and the 
dimensions of all electrical units can be specified as follows, without any arbitrary 
convention or distinction between electrostatic and electromagnetic units. 
strain area LT? 
Sp. ind. cap. K = = ~~ = — = shearabilit 
= te stress force M . 
inertia M ae let 
= —— = — = densi 
volume L# if 
: volume 
Electric charge = L? = ———— 
displacement 
} M ; 
Magnetic pole = T momentum per unit length 
L2 
Electric current = acy displacement X velocity 
, ML 
Magnetic moment = ang momentum 
work M : $ 
E. M. F. = Qn = a pressure X displacement, or work per unit area 
: - E 3h : 
Intensity of magnetic field, H = Ae = velocity 
: ; Fr M : 
Intensity of electrostatic field, Q — br = energy per unit volume 
Surface density = a pure number 
Electric tension = —— = a pressure or tension 
LT? 
