[     ™     ] 
IV.  A  Modified  Form  of  Apparatus  for  the  Determination 
of  the  Dielectric  Constants  of  JS^on- Conducting  Liquids.  By 
V.  H.  Yeley,  F.R.S* 
WITHIN  recent  years  the  determination  o£  the  dielectric 
constants  of  liquids  has  attracted  considerable  atten- 
tion, partly  on  account  of  the  simplification  of  the  methods, 
and  partly  with  a  view  of  ascertaining  the  validity  of  the 
Maxwell  equation 
(n2-l)M/(^  +  2)d  =  (K 
or  that  of  Olausius  and  Mosotti 
l)M/(K  +  2>7, 
(1) 
K=l  +  2d/l-d. 
(2) 
As  regards  the  latter  point  the  determinations  have  led  to 
no  satisfactory  conclusion  ;  but  as  regards  the  former,  the 
application  of  the  bridge  method,  the  substitution  of  the 
telephone  for  the  galvanometer  or  electrometer,  of  liquid 
resistances  (Nernstf)  for  many  yards   of  wire   (Paluzf)  or 
Fur.  1. 
high-resistance  coils,  have  all  served  to  simplify  and  render 
more  accurate  determinations  based  upon  the  conditions  of 
balance  according  to  the  principle  represented  by  the  diagram 
(fig- 1). 
*  Communicated  by  the  Author. 
f  Zeits.f.  p/ujs.  Cheyn.  xiv.  p.  622  (1894). 
\  Journ.  de  Phys.  [2]  v.  p.  270  (1885). 
