1$54.] OF THE ROYAL INSTITUTION. 347 
Consider now an insulated battery of 360 pairs of plates (4x3 
inches) having one extremity in contact with the earth, the water wire 
with both its insulated ends in the room, and a good earth discharge 
wire ready for the requisite communications :—when the free battery 
end was placed in contact with the water wire and then removed, 
and, afterwards, a person touching the earth discharge touched also 
the wire, he received a powerful shock. The shock was rather 
that of a voltaic than of a Leyden battery: it occupied time, and 
by quick tapping touches could be divided into numerous small 
shocks: I obtained as many as 40 sensible shocks from one charge 
of the wire. If time were allowed to intervene between the charge 
and discharge of the wire, the shock was less: but it was sensible 
after 2, 3, or 4 minutes, or even a longer period. 
When, after the wire had been in contact with the battery, it was 
placed in contact with a Statham’s fuze, it ignited the fuze (or even 
6 fuzes in succession) vividly: — it could ignite the fuze 3 or 4 
seconds after separation from the battery. When, having been in 
contact with the battery, it was separated and placed in contact 
with a galvanometer, it affected the instrument very powerfully : — 
it acted on it, though less powerfully, after the lapse of 4 or 5 
minutes, and even affected it sensibly 20 or 30 minutes after it 
had been separated from the battery. When the insulated galvano- 
meter was permanently attached to the end of the water wire, and 
the battery pole was brought in contact with the free end of the 
instrument, it was most instructive to see the great rush of elec- 
tricity into the wire; yet after that was over, though the contact 
was continued, the deflection was not more than 5°, so high was the 
insulation. Then separating the battery from the galvanometer, and 
touching the latter with the earth wire, it was just as striking to 
see the electricity rush out of the wire, holding for a time the 
magnet of the instrument in the reverse direction to that due to 
the ingress or charge. 
These effects were produced equally well with either pole of the 
battery or with either end of the wire; and whether the electric 
condition was conferred and withdrawn at the same end or at the 
opposite ends of the 100 miles, made no difference in the results. 
An intensity battery was required, for reasons which will be very 
evident in the sequel. That employed was able to decompose only 
a very small quantity of water in a given time. A Grove’s 
battery of 8 or 10 pair of plates, which would have far sur- 
passed it in this respect, would have had scarcely a sensible power 
in affecting the wire. 
When the 100 miles of wire in the air were experimented with 
in like manner, not the slightest signs of any of these effects were 
produced. There is reason, from principle, to believe that an 
infinitesimal result is obtainable, but as compared to the water 
wire the action was nothing. Yet the wire was equally well and 
better insulated, and as regarded a constant current, it was an 
