Peter Barlow to Faraday   4 February 1822

Royl Mily Acady | Feby 4th 1822

Dear Sir

I have been attempting to repeat your experiments, in which I should have succeeded perfectly well if my battery would but maintain its first power long enough, but for some reason which I cannot discover all its energy is gone in a few minutes. I have determined therefore to convert the plates of it into a Calorimoter. I have 20 pairs - 10 inches square and I only want to know how they are fixed in the frame. The description which I find in Brewsters Journal is not sufficiently explicit¹. I understand the arrangement, to be as follows - first, 10 zinc plates are soldered to one strip of tin and the other 10 zinc to another strip and the same with the copper, and that they are inserted into each other as in the figure[.]

Permit me to ask you

1st Whether that arrangement be correct?

2d Whether there is a bottom to your frame to rest the plates on? It appears to me that they would not be sufficiently strong without some such support[.]

3 Which are the poles of the machine? viz the parts from which the connecting wires proceed[.]

4thly Will you give me any other little hints which you think is requisite to suit a novice in the Galvanic art?

I hope you may be able to answer me these questions in a few words as I am well convinced that your time is too much occupied to trifle it away in such a manner. Unfortunately I have only the saturday now that I can come to town or I would have called on you and learned all the above particulars from inspection and Saturday I remember you said was a day on which you were more particularly engaged than any others.

I remain Dear Sir Yours very truly | Peter Barlow

Are the two series of copper plates and the two of zinc connected with each other - or entirely detached as in the figur<<e.>>

Address: Faraday Esq | Royal Institution | Albemarle Street