1854.] OF THE ROYAL, INSTITUTION. 349 
gether offer a beautiful case of the identity of static and dynamic 
electricity. The whole power of a considerable battery may in this 
way be worked off in separate portions, and measured out in units 
of static force, and yet be employed afterwards for any or every 
purpose of voltaic electricity. 
I now proceed to further consequences of associated static and 
dynamic effects. Wires covered with gutta percha, and then in- 
closed in tubes of lead or of iron, or buried in the earth, or sunk 
in the sea, exhibit the same phenomena as those described; the 
like static inductive action being in all these cases permitted by the 
conditions. Such subterraneous wires exist between London and 
Manchester, and when they are all connected together so as to 
make one series, offer above 1500 miles; which, as the duplications 
return to London, can be observed by one experimenter at intervals 
of about 400 miles, by the introduction of galvanometers at these 
returns. This wire, or the half, or fourth of it, presented all the 
phenomena already described ; the only difference was, that as the 
insulation was not so perfect, the charged condition fell more 
rapidly. Consider 750 miles of the wire in one length, a galvano- 
meter a being at the beginning of the wire, a second galvanometer 0 
in the middle, and a third c at the end:—these three galvanometers 
being in the room with the experimenter, and the third c perfectly 
connected with the earth. On bringing the pole of the battery 
into contact with the wire through the galvanometer a, that in- 
strument was instantly affected; after a sensible time 6 was affected, 
and after a still longer time c: when the whole 1500 miles were 
included, it required two seconds for the electric stream to reach 
the last instrument. Again ;—all the instruments being deflected, 
(of course not equally because of the electric leakage along the 
line,) if the battery were cut off at a, that instrument instantly fell 
to zero; but 6 did not fall until a little while after; and c only after 
a still longer interval; —a current flowing on to the end of the 
wire whilst there was none flowing in at the beginning. Again; 
by a short touch of the battery pole against a, it could be deflected 
and could fall back into its neutral condition, before the electric 
power had reached 6; which in its turn would be for an instant 
affected, and then left neutral before the power had reached c; a 
wave of force having been sent into the wire which gradually 
travelled along it, and made itself evident at successive intervals of 
time, in different parts of the wire. It was even possible, by ad- 
justed touches of the battery, to have two simultaneous waves in 
the wire, following each other, so that at the same moment that 
ce was affected by the first wave, a or b was affected by the second ; 
and there is no doubt that by the multiplication of instruments 
and close attention, four or five waves might be obtained at once. 
If after making and breaking battery contact at a, a be immediately 
connected with the earth, then additional interesting effects occur. 
Part of the electricity which is in the wire will return, and passing 
