Faraday to George Biddell Airy   3 November 1829

Royal Institution | Nov. 3. 1829

My dear Sir

I should have been very happy to have met your wishes as to the glass either by sending you a piece directly or applying to the Committee for leave to do so but that the investigation is not as yet in such a perfect practical state as to allow it[.] Whilst every fresh experiment enables me to improve the glass either as to its composition colour hardness &c or as to the process by which it is made we do not think it perfect and I am unwilling to give any specimens of an incomplete manufacture out of my hand[.] When having obtained the best composition I am also assured by continual experience that I can make the glass I desire again & again then I shall feel proud to place specimens in the hands of Amici but at present and up to the present I have found reason to vary every experiment from the preceding one[.]

Capt Kater one of the glass committee is himself waiting for a piece of glass for experimental purposes and it is my earnest wish to supply him & Professor Amici & all others who can & will investigate the properties of the glass with specimens. But the experiments are very laborious & prolonged and were it not for the continually increasing views of success which have presented themselves I should long ere this have thrown them up altogether[.]

I am dear Sir | Very Truly Yours | M. Faraday

Professor Airy | &c &c