SCIENTIFIC SUMMARY. 
281 
the apparatus under command that one of the four batteries was detached 
from the rest, and carried to another place to supply the force required for 
an electric cautery. A single battery, when recharged, was left alone for 
ten days, and then it yielded to Sir William Thomson 200,000 foot pounds, 
so that the original estimate of a million foot pounds for the whole box was 
probably somewhat under the mark. Further investigations are required in 
order to discover what are the limits, if any, of the power to preserve elec- 
tric energy unwasted ; but sufficient is known to show that it can be pre- 
served long enough for many important practical applications. That which 
Sir William Thomson regards as likely to be the first, at least in point of 
time, is the use of Faure’s batteries in private houses, as reservoirs of elec- 
tricity for domestic purposes, such as lighting, heating, working of sewing 
machines, so that no interruption of action would be produced by a tempo- 
rary interruption of the electric supply given by any main engine from which 
it was derived. 
1 Sir William Thomson reminds us that the storage of force to be after- 
wards put to practical uses is a very old contrivance, of which we may see an 
illustration in the winding of a watch ; and also the storage of electricity 
has long been familiar to men of science as a theoretical possibility. There 
is often a long step, however, from theoretical possibility to practical achieve- 
ment ; and what we are now called upon to notice is no longer that such a 
storage may perhaps be accomplished at some future time, but that it has 
actually been accomplished upon what may almost be called a working 
scale. Many philosophers are of opinion that electricity, at no distant date, 
will entirely supersede fires for cooking and heating, steam as a motor, and 
gas and oil as illuminants ; but hitherto it has been felt as a great difficulty, 
economical rather than scientific, that the agents proposed to be superseded 
were themselves actually employed to produce the electricity. It has been 
asserted, moreover, that the sectional area of the metallic conductors required 
to deliver electricity in quantities suited to the requirements of town com- 
munities would have to be enormously large, and in a corresponding degree 
costly ; and that difficulties with regard to insulation would be of constant 
occurrence. But electricity is to be obtained from the atmosphere by simple 
mechanical means wherever any kind of motive power is available ; and, if 
it can be stored in portable batteries and carried about for use, there seems 
to be no reason Avhy it should not be obtained in very cheap ways, as by 
wind or water mills, by mechanical contrivances for utilizing the ebb and 
flow of the tides, or by other applications of the power which nature 
everywhere offers for the use of man, and which is so frequently suffered 
to run waste.’ 
1 Sir, — The marvellous “ box of electricity ” described in a letter to you, 
which was published in the Times of May 16, has been subjected to a variety 
of trials and measurements in my laboratory for now three weeks, and I 
think it may interest your readers to learn that the results show your correspon- 
dent to have been by no means too enthusiastic as to its great practical value. 
I am continuing my experiments to learn the behaviour of the Faure battery 
in varied circumstances, and to do what I can towards finding the best way 
of arranging it for the different kinds of service to which it is to be applied. 
