Faraday to Jacob Herbert¹   24 February 1853

Royal Institution | 24 February 1853

Dear Sir

On Tuesday last² an examination was made at the Trinity House into the relative merits of the French lens, belonging to the frame in the experimental room, and a corresponding lens recently manufactured by the Messrs Chance of Birmingham; which for the purpose of comparison was attached to the same frame. According to my judgment the forms, and adjustment of the different portions of glass of Mr Chance’s lens are as perfect as in the French lens, and the light from the lamp therefore as well and properly dispersed on the distant screen. The colour of all parts of Mr Chances lens appeared to me by artificial light the same and very good; and equal to the great central part of the French lens. The upper and lower ribs of the French lens were slightly green, and therefore slightly inferior in that respect. On the whole I consider the lenses as being very equal in power and quality³.

I am | My dear Sir | Your very faithful Servant | M. Faraday

Jacob Herbert Esqr | &c &c &c