Ok») 
V. 
ELECTRO-MAGNETIC MASS. 
By ARTHUR W. CONWAY, M.A., F.R.U.I., 
Professor of Mathematical Physics, University College, Dublin. 
[ Published, Marcu 28, 1907. | 
CONTENTS. 
Page Page 
I. Introduction, . : : 3 5 Gil VY. The Retarded Potential, . ; . 505 
IL, “Wi Granta! Belay, : wee VI. The Coefficients of Induction, . > BT 
III. The Fundamental Assumption, . 5 3 
TY. Deductions of Expressions for VII. Newtonian Mass, 5 ; : SO 
Momentum and Energy, j » &S 
I.— INTRODUCTION. 
In the formation of a rational scheme of electrodynamics two groups of 
assumptions are necessary. In the first place, principles must be laid down 
for deducing the values of the electric and magnetic forces in terms of the 
distribution and motion of the electrons. In the Maxwellian scheme this is 
effected by the circuital relations, or by what is equivalent to them, certain 
direct assumptions as to the values of the electro-magnetic vectors.* In the 
second place, hypotheses must be proposed which will determine the motion 
of various distributions of electrons in terms of the field of force in which 
they are situated. This involves expressions for energy, energy flux, momentum 
coefficients of self-induction, mass, etc. It is the object of the present paper 
to deduce all these expressions from a single principle-—the inequality of 
action and reaction. Starting with any assigned system of electrical matter 
moving in a general manner, the values of the electrical and magnetic forces 
become completely definite. The electromotive forces experienced by any 
portion of this system consist of two parts—one arising from other parts of 
* Trans. Roy. Dublin Soc., vol. viii., part iii, 
TRANS. ROY. DUB. SOC., N.S., VOL. IX., PART VY. L 
