326 
POPULAR SCIENCE REVIEW. 
Experiment alone can demonstrate tlie practical value of tlie 
Faure accumulator ; but Sir William Thomson thinks that it 
will not be too heavy to place on board a tram-car or an omnibus, 
in order to drive the vehicle by its charge in preference to 
horses. This would be effected by reversing the arrangement 
shown in Fig. 4, and causing the discharge of the battery, B, to 
rotate the coil, C ; the motion thus produced being, of course, 
communicated to the wheels of the carriage. In the Siemens 
electric railway in Berlin, the electricity is conveyed by a wire 
along the track from a stationary generator at one terminus of 
the line to the coil of a dynamo- electric machine attached to the 
locomotive ; but there are cases of locomotion in which this plan 
cannot be followed. Omnibuses, for instance, require to be in- 
dependent of such a wire, so do boats, balloons, and tricycles. 
The electricity required to turn the wheels of such free and 
independent vehicles must therefore be carried with them, either 
in a voltaic battery, from which it can be got at first hand, or 
in a secondary battery, giving it at second hand. But in point 
of lightness and convenience, the secondary battery is far 
superior to the other, so that we may expect it to be preferred. 
Becent experiments, by M. Trouve of Paris, have shown that 
boats, launches, and velocipedes, may be successfully driven by 
the electric current ; and the prospect is all the better now that 
M. Faure’ s secondary battery has come out. 
In surgery it has already proved its usefulness in the hands 
of Prof. George Buchanan, of Glasgow, who excised a nsevoid 
tumour from the fore-tongue of a lad, without losing a drop of 
blood, through the agency of a wire heated to redness by the 
current stored in a Faure battery, 9 inches high by 5 inches in 
diameter. It is in electric lighting, however, that the Faure, or 
at any rate some other secondary battery, will be most valuable. 
According to Sir William Thomson, a battery of seven cells, of 
the above size, is sufficient to keep four or five of the electric 
lamps of Mr. Swan glowing for at least six hours, with a total 
luminous effect of 100 candles ! It follows that with several of 
such batteries stationed in a house, and charged with electricity 
during the day by means of wires from the works where the 
current is generated, it will be possible to light np the rooms 
by night, and perform such light operations as turning a coffee- 
mill or a sewing-machine. The same battery will drive a 
sewing-machine several hours a-day for a week. In fact, it is 
not going too far to say that an electric reservoir will be as 
much a part and parcel of the home in future as a water- 
cistern or a coal-.bin is to-day. 
