Faraday to Samuel March Phillipps   19 July 1838

R Institution | 19 July 1838

Sir

I am in town for a day only but hasten to answer your letter¹. I feel much diffidence in forming an opinion respecting the effect of the Air of the Metro‑polis on the Cartoons without previous consultation with those who have been conversant with such action but to avoid delay will state at present that I should not anticipate any harm from the chemical action of the air either upon the colours or upon the vehicle or medium by which they are attached or upon the canvass & paper on which they are applied[.]

But there is another effect of the London atmosphere brought to my mind by Mr Phillips of the Royal Academy from which I should fear much harm I mean the dirtying effect. The ceilings & walls of a London room sufficiently show to what extent dirt in the form of dust may penetrate surfaces & textures like those of the distemper painted Cartoons. In oil paintings the dust if it adheres is stopped upon the surface & the substances applied for its removal need not pass through the varnish; so that the colours them‑selves are not necessarily at any time either injured by or in contact with the dirtying or the cleansing medium. But in such paintings as the Cartoons the dust has access to the very colours & body of the picture & then cannot be dislodged without causing the destruc‑tion, or something very like it, of the whole[.]

As I see no effectual way of preventing the access of dirt to the pictures I fear that the evil thus arising may in the Metropolis be very considerable and produce an effect in the lapse of 30, 40, or 50, years which could never be remedied[.]

I have the honor to be | Sir | Your Obedient Humble Servant | M. Faraday

John [sic] Phillip[p]s Esq | &c &c &c | Whitehall