CR 
( 224 ) ea 
experimental condenser, ¢ that of the experimental condenser with 
vacuum as a medium, Then we have as above in equation (3) 
do  ®+e 
fien 
or 
d 
Ey By OS hy ein Pee 
When the experimental condenser is now filled with a dielectric 
fluid its capacity will be altered to c’ and a considerable movement 
of the glass plate will certainly be required to compensate it. 
If we call the capacity of the condenser in this third position ag, 
then we have in analogy with the foregoing 
d 
ig = Bp ol Ba Set 
Y 
The differences «)— 7); %)— 7g can be immediately read off. In 
the same way we may express the difference c' — c as a measurable 
quantity from (4) and (5). From this we can determine the value 
of d'/e if we know the value of ce, which can be obtained by mea- 
surements in which the value of 7 is purposely varied. But we find 
that the differences of the readings occurring in the observations are 
so small that the value of c cannot be determined to a greater 
accuracy than 10 °/, and is hence useless. A determination of 
the value of z,d/y is required, and this can be made once for all 
by cutting off the lead close to the condenser and fixing it in almost 
exactly the same position as before by means of wax, but insulated 
from the condenser. One can now convince oneself that the error 
produced in fixing the wire does not reach 0.2 mm., by loosening 
and refixing it, moreover the error occurs equally in the numerator 
and denominator of the expression for the dielectric-coefficient. In 
the same way the capacity of the wire can be determined, by pro- 
ceeding with the lead in exactly the same way as with the whole 
condenser, and thus arriving at the equation 
en Terr lend ond ue eN 
ds 
and henee 
' 
tp mick IO 
HEE 
