, 69 NOTES.

Neglecting the term —ą in the denominator we see that under tne-

influence of the collisions the phenomena will be the same, as if there
were a resistance determined by

2m

B8 (Page 147). In the case of a mixture the electric moment
r is made up of as many parts P1? P2, ... as there are constituents.
Beaaoning as in §§116—119 we can establish for each component
formulae like (200), so that, if we put a = -J-, we have for the first
substance

for the second

*M ' —~s — F 4_ _L P _ f'p
2 gŁ2 '3 — ' * 2 >

and so on. Hence, if .all the dependent variables vary, as s*nt,

p ... E + ^p P _

vT ^ "~~" j-ť / ~~~f a Ť fl 9 *~~"

x y-......... ^yj, 71 - '

and, if we put

___1____, • 1 +

Combining this with (192) we find

and for the index of refraction

JL

3

Now each term -^IT^V) S^68 tlie value of ^"2 for one of
tiie constituents taken with the density my which it has in the
mixture, a value that is found when we multiply the constant r for tie
constituent in question by the density my. This immediately leads
to equation (218).

(Page 149). According to the equations (220), if we put
a — •Ł, the displacements &, |2, ... are determined by

(ft - w^ii - \ (E, + \PJ, etc.-particles for which the interval & lies