destructive of power and of the plant itself in starting and stopping,
would be saved, and that perfect immunity from products of combustion
would be insured The experience at Lichterfelde, at Paris, and another
electric line of 765 yards in length, and 2 ft. 2 in. gauge, worked
in connection with the Zaukerode Colliery since October, 1882, were
extremely favorable to this mode of propulsion. The lecturer however
did not advocate its prospective application in competition with the
locomotive engine for main lines of railway. For tramways within
populous districts, the insulated conductor involved a serious
difficulty. It would be more advantageous under these circumstances to
resort to secondary batteries, forming a store of electrical energy
carried under the seats of the car itself, and working a dynamo machine
connected with the moving wheels by means of belts and chains.

The secondary battery was the only available means of propelling vessels
by electrical power, and considering that these batteries might be made
to serve the purpose of keel ballast, their weight, which was still
considerable, would not be objectionable. The secondary battery was not
an entirely new conception. The hydrogen gas battery suggested by Sir
Wm. Grove in 1841, and which was shown in operation, realized in the
most perfect manner the conception of storage, only that the power
obtained from it was exceedingly slight. The lecturer, in working upon
Sir Wm. Grove's conception, had twenty-five years ago constructed
a battery of considerable power in substituting porous carbon for
platinum, impregnating the same with a precipitate of lead peroxidized
by a charging current. At that time little practical importance attached
however to the object, and even when Plante, in 1860, produced his
secondary battery, composed of lead plates peroxidized by a charging
current, little more than scientific curiosity was excited. It was
only since the dynamo machine had become an accomplished fact that