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POPULAR SCIENCE REVIEW. 
At the request of the Conseil d’Administration of the Societe de la Lumiere, 
I have gladly undertaken this work, because the subject is one in which I 
feel intensely interested, seeing in it a realization of the most ardently and 
unceasingly felt scientific aspiration of my life — an aspiration which I scarcely 
dared to expect or to hope to live to see realized. 
‘ The problem of converting energy into a preservable and storable form, 
and of laying it up in store conveniently for allowing it to be used at any 
time when wanted, is one of the most interesting and important in the whole 
range of science. It is solved on a small scale in winding up a watch, in 
drawing a bow, in compressing air into the receiver of an air-gun or of a 
Whitehead torpedo, in winding up the weights of a clock or other machine 
driven by weights, and in pumping up water to a height by a windmill (or 
otherwise, as in Sir William Armstrong’s hydraulic accumulator) for the 
purpose of using it afterwards to do work by a waterwheel or water pressure 
on a piston. It is solved on a large scale by the application of burning fuel to 
smelt zinc, to be afterwards used to give electric light or to drive an electro- 
magnetic engine by becoming, as it were, unsmelted in a voltaic battery. 
Ever since Joule, forty years ago, founded the thermodynamic theory of 
the voltaic battery and the electro-magnetic engine, the idea of applying the 
engine to work the battery backwards, and thus restore the chemical energy 
to the materials so that they may again act voltaically, and again and again, 
has been familiar in science. But with all ordinary forms of voltaic battery 
the realization of the idea to any purpose seemed hopelessly distant. By 
Plante’s admirable discovery of the lead and peroxide of lead voltaic battery, 
alluded to by your correspondent, an important advance towards the desired 
object was made twenty years ago; and now by M. Faure’s improvement prac- 
tical fruition is attained. 
1 The “ million of foot pounds ” kept in the box during its seventy-two 
hours’ journey from Paris to Glasgow was no exaggeration. One of the four 
cells, after being discharged, was recharged again by my own laboratory 
battery, and then left to itself absolutely undisturbed for ten days. After 
that it yielded to me 260,000 foot pounds (or a little more than a quarter of 
a million). This not only confirms M. Beynier’s measurements, on the face 
of which your correspondent’s statement was made; it seems further to show 
that the waste of the stored energy by time is not great, and that for days 
or weeks, at all events, it may not be of practical moment. This, however, 
is a question which can only be answered by careful observations and mea- 
surements carried on for a much longer time than I have hitherto had for in- 
vestigating the Faure battery. I have already ascertained enough regarding its 
qualities to make it quite certain that it solves the problem of storing electric 
energy in a manner and on a scale useful for many important practical appli- 
cations. It has already had in this country one interesting application, of 
the smallest in respect to dynamical energy used, but not of the smallest in 
respect to beneficence, of all that may be expected of it. A few days ago 
my colleague, Prof. George Buchanan, carried away from my laboratory one 
of the lead cells (weighing about 18 lbs.) in his carriage, and by it ignited 
the thick platinum wire of a galvanic ecraseur and bloodlessly removed a 
naevoid tumour from the tongue of a young boy in about a minute of time. 
The operation would have occupied over ten minutes if performed by the 
