Faraday to John Hennell¹   2 June 1843

Royal Institution | 2 June 1843

Dear Sir

The water you describe must I conclude be very hard principally from Carbonate of lime. I do not remember what [name illegible] Patent filter is but filtration if quick might do but little separating only a little of the lime & if slow would probably soon block up the filter i.e in a few months or a twelvemonth. Boiling you say produces a dark scum[.] I should have expected rather a fine white or brownish. Boiling ought to make it softer and filtering after boiling ought to make it good.

With my best remembrances to Mrs. Hennell²

I am | My dear Sir | Your Obedient Servant | M. Faraday

John Hennell Esq | &c &c &c

I have no other address on your letter than Coventry. I hope that will lead to no mistake.