210 Scientific Intelligence. 
those made with dry, and second, that the better the dielectric 
conducted, the greater the charge the condenser was capable o 
receiving. From these facts it would seem that the slow = 
tion. e best condensers, as shown by the experi iments, pos- 
all. Their conduction when moist must therefore have been 
mainly due to electrolysis, since liquids conduct electricity 
only in very small quantities without being decom The 
electrolyte was therefore decomposed, and the re-combination 
of the products of decomposition caused the return current. 
An exact analogy is thus determined between the case of the 
lead plates and these condensers. Whether it is an analogy 
that would hold in the case of all condensers which slowly dis- 
charge themselves, is an interesting question 
SCIENTIFIC INTELLIGENCE. 
I. Purysics. 
Dielectricity of pate Dn —M. L. ec aiaiputgs has presented 
to :o Vienna Academy of Sciences a paper n experimental 
determination of the constant of dielectricity of iulache bodies. 
Faraday first observed the property of insulating solid bodies of 
ng. dielectric, that is, of increasing the capacity of a condenser 
by their presence etween its two plates. Sew tty and later 
Gibson rs cence have studied the phenomeno ex perimen- 
sEevctioal conditions. Representing by Pat and ie the differ- 
ential ratios of the potential on the inner and outer faces of the 
dv eee 
ie Te he 
insulator, along the normal, the quotient Ne) ING will be t 
constant of dielectricity D. Neglecting the free singe | ac- 
omer bp at the borders of the plates of” the condense all- 
the distance of the two plates, or the thickness of ‘the S dinlee- 
tric dayer, the greg of the condenser will be inversely propor 
tional to m—n+—. 
The measurement sa = opae of pment was goon Pat a 
: athe? s charged by a bat- 
phur and aie | then as im insulators, stearine, 
‘glass ee pa percha, The theoretic siiechenlente of Helmholtz 
