540 
PROFESSOR. H. LAMB OR ELECTRICAL 
We notice that these conditions give 
la-\-mb'-\-nc'=la"-\-mb" J r nc" .(85), 
as ought to be the case. In fact (85) is implied in the continuity of F, G, H. 
8. Proceeding now to the case of a spherical conductor, let the origin be taken at 
the centre, and let r be the radius vector of any point. Let us begin with the 
solutions of the First Type, the formulae for which are given by (27), (32), (34), (35). 
The continuity of F, G, H gives as before 
— X.(86) 
at the surface (r=P). In applying (84) we remark that, at the surface, 
ld+mb'+nc'= — 
and hence that 
l(la +7 nb -j-nc )= — 
by (36). Hence (84) give 
+ l)r/f„(kE) jx«=/rX«.(87), 
with another condition which may however be shown to be included in (86) and (87). 
The formulae for the solutions of the Second Type are given in (40), (42), (43), (44). 
The surface conditions (84) yield 
xp u (MV).0)^=0 .( 88 ). 
9. In the case of free currents of the first type we have X„ = 0, and the equation to 
determine Tc is 
i/l_!(MI) +^-^(p—l)xp /l (TR)=0 .(89). 
When, as in iron, /x is a very large number, we have, as a first approximation, 
If JcR=3- be a solution of this, a second approximation is 
. < 90 >' 
When the values of Zdt have been found, the corresponding values of the modulus 
of decay are given by 
