THE ELECTRICAL RESISTANCE OF THIN LIQUID FILMS. 
4G7 
give the following: The symbols X and || mean that the wire bridges of the 
electrometer reversing arrangement are crossed and parallel respectively. 
September 27, 1880.—Film I., needles 2-3, resistance in boxes =508,000 ohms=R. 
Part of circuit which is connected 
with electrometer. 
X X 
Deflection. 
Time. 
Deflection. 
Time. 
Needles (no current passing) 
0 
2 right 
Mean = 
1 
h. 
m. 
s. 
h. m. 
S. 
Film. 
80 right 
12 
54 
12 
75-5 left 
12 55 
6 
Resistance. 
174 
54 
42 
166 
55 
30 
Film. 
82-5 
56 
0 
79 
57 
0 
Resistance. 
167 
56 
30 
159-5 
57 
30 
Film. 
85-5 
58 
0 
82 
59 
0 
Resistance. 
159-5 
58 
30 
151-5 
59 
30 
Needles. 
0 
2 right 
Mean - 
1 
Film. 
91-5 
1 
1 
0 
85-5 
1 2 
0 
Resistance. 
149-5 
1 
30 
140 
3 
12 
Film. 
93 
3 
42 
90 
4 
30 
Resistance. 
140 
4 
6 
133-5 
5 
0 
Film. 
96-5 
5 
30 
91-5 
6 
30 
Resistance . 
135-5 
6 
0 
127 
7 
0 
Needles . 
•5 right 
2 5 right 
Mean = 
1 
These observations were continued until l h 22 ,u , when the him burst. The numbers 
thus obtained were then plotted down on a sheet of curve paper, times being repre¬ 
sented as abscissae and deflections as ordinates. Thus, four curves were drawn, of 
which F (right) and F (left) gave the mean him curve, and R (right) and R (left) the 
mean resistance curve. The curves F (right) and F (left) were always very close 
together and sometimes coincident, but, as the zero of the electrometer was liable to 
change, the curves for both right and left deflections were always drawn and the mean 
taken. The same remarks apply to the curves of resistance-deflections. From the two 
mean curves thus obtained a third is deduced as follows : The ordinates of the curves 
are read off at points separated by intervals of four minutes, and when the proper 
corrections, described above, have been made, the hlm-dehection is divided by the 
resistance-deflection and the quotient multiplied by the resistance of the coils. A 
curve passing through the series of points so obtained enables us to determine the 
resistance of the film between the two needles at any epoch. 
mdccclxxxi. 3 p 
