Faraday to Peter Henry Berthon   6 October 1857

Royal Institution | 6 Octr. 1857.

Sir

The machine (of which a drawing & description has been sent to me¹) called “Barbarin & Sims Electro Magnetic fog bell” resolves itself into two parts one a clock working by ordinary mechanical power (apparently a spring) the other an Electro magnetic machine to lift the hammer & spring not shewn in the drawing by which the bell is to be struck at regular intervals determinable by the clock. The Voltaic battery & its associated arrangements have no other purpose than to perform mechanical work, exactly as any other power as that of a man horse or steam engine would do it. The work to be done is the lifting up of the hammer & the spring upon it:- and the machine, to be of any advantage, must either supply the requisite power more cheaply than other sources of force or it must be a source of force more convenient & available than any other which can be conveyed to a given station.

As to the expense of the force all attempts hitherto made have shown that it is greater with the Electro magnetic machine than with steam or horse or man power and I have not the slightest idea of any advantage in the respect. As to any particular convenience the machine may possess I do not find that such are mentioned in the description nor does any occur to me. The apparatus would require a peculiar kind of care and I expect could not be so safely left to itself as an ordinary machine supplied with a descending weight or any other motor. If a man be left in charge of it then I think it probable that the man power might be more cheaply & safely applied than the power of the Electro magnetic machine[.]

Nothing can be easier than to try the machine and obtain proof of its ability but certainly such trials should not be made at a station but at home. All that is necessary is so to arrange the apparatus that it shall lift a weight; to ascertain what weight it can lift in a certain number of hours, to a given height, and at what expence; & then compare these results with an ordinary apparatus & the price of man power sufficient to do the same work. Whilst this comparison is being wrought out any other supposed advantages (though I do not find that such are referred to) can be observed and considered²[.]

I am Sir | Your very faithful Obedient Servant | M. Faraday

P.H. Berthon Esqr | &c &c &c