George Gabriel Stokes to Faraday   14 February 1853

Pembroke College, Cambridge | Feb 14th 1853

My dear Sir,

You will receive I hope some time tomorrow a tin case containing some diagrams. I enclose you the key. Will you have the goodness to order them to be laid flat? I do not think that I shall use more than the 4 outside ones; I merely send the rest for fear I should wish for them and regret having left them behind. They are what I used at Belfast¹, and they have got a good deal dirtied and rubbed. Will you have the goodness to look at the four outside ones, to see if you think they are decent to produce before a London audience? If not, perhaps there would be time to have them copied or retouched.

I intend to go to the Royal Institution on Thursday evening². I should be glad to have some oxygen ready, as I wish to try some more experiments with the sulphur light. I think it would be possible, and interesting, to show the audience some chemical reactions observed by means of the effects produced by the media on the invisible rays. For this purpose I should wish to have a little of a solution of quinine, (not a quinine salt) in alcohol.

I have found an easy way of purifying the horse-chestnut solution. I mean to bring some of the purified solution with me, but in case of any accident please tell Anderson to make a decoction of a good part or the whole of the bark which is left, to the fluid decanted or filtered, to add a little carbonate of ammonia, and then leave it in a shallow open vessel, so as to be exposed to the air. It requires a day or two’s exposure. It will be time enough when I come to go on with the process.

I should be very sorry that you should forego any engagement on my account. Anderson can attend me. Indeed you have always got one engagement, namely to go on with your most important investigations.

I should like a little hydrogen as well as oxygen, to try the effect of the lime light once more with absorbing media.

I am dear Sir | Yours very truly | G.G. Stokes