136 Professors Ayrton and Perry on the Measurement 
platinum wires were each 1^ centim. above the lower ends of 
the glass tubes ; and the lower ends of the glass tubes were 
1 centim. below the surface of the water. The two platinum 
plates and one of the platinum wires were kept immovable, 
while the other platinum wire was moved along the trough. 
February 21, 1878. 
Distance 
between pla- 
Time after 
Galvanome- 
Electrometer- 
Temperature 
putting on 
ter-deflection. 
deflection. 
of water. 
tinum wires. 
battery. 
centim. 
m s 
rso 
1 
669 
53 
"] 
aJ 60 
A ]40 
1 30 
662 
40 
L 13° C. 
1 50 
658 
27 
[20 
2 15 
654 
15 
J 
(80 
1 
667 
52 
1 
1- 13° C. 
-o 60 
B 40 
1 25 
663 
39 
1 45 
657 
27 
[20 
2 10 
653 
15 
February 22, 1878. 
rso 
1 
680 
30 
I 
n l60 
C l40 
1 35 
2 10 
675 
672 
37 
26 
I 13° C. 
[20 
2 30 
670 
15 
J 
f80 
1 
685 
49 
] 
D 60 
■"l 40 
1 20 
680 
37 
[ 13° C. 
1 50 
677 
24 
[20 
2 10 
674 
12 
) 
rso 
1 
697 
48 
] 
17 60 
E l40 
1 20 
692 
36 
[ 13° C. 
1 50 
688 
24 
[20 
2 20 
685 
13 
) 
rso 
v 60 
F 40 
[20 
1 
699 
50 
] 
1 35 
1 50 
694 
690 
37 
25 
[ 13° C. 
2 15 
687 
13 
J 
180 
1 
over 717 
51 
] 
G 60 
^140 
30 
2 
" 
38 
25 
I 13° C. 
[20 
2 20 
» 
15 
J 
The object, of course, of taking the galvanometer-readings 
was to ensure that no material change was taking place in the 
current through the weakening of the battery or otherwise 
while the experiment was being made. 
The experiments E and F appear most satisfactory of this 
set ; and from these it seems that the resistance of the upper 
layer of water-column is nearly proportional to the distance 
between the platinum wires, except for the nearest distance, 
