John Frederick William Herschel to Faraday   27 August 1827

Slough Aug 27. 1827

My dear Sir

I shall be in town I expect in the course of the next week and as you mention the probability of your remaining there with only occasional short absences I will take care and find an opportunity of meeting. It would be desirable if possible to get the building done before the Society meets and both myself and Dollond will unhesitatingly defer to your judgement as to the plan & construction of it so that no delay need take place on our account in proceeding to work.

I shall of course give to the subject as much attention as possible, my resignation of the Secretaryship in no [MS torn] way interfering with my duties as one of the Committee. Residing as I shall now chiefly do however at a distance from Town it will not be in my power to give so much of my personal attendance to the experiments as under other circumstances I might. But to the utmost extent of my abilities I am only desirous to make myself useful.

I have just got some new prisms from Utzschnieder’s¹ manufactory among which is a large one of flint glass of the utmost perfection being like a piece of solidified water without a trace of a vein or imperfection of any kind. This shews that their glass may be depended on & that the problem is capable of being resolved.

One of my notions which it will be well to put to the test was to form glass of Lithage and Silex alone, in such proportions to very nearly to saturate the former. In this state I conceive that the action of the crucibles would be effectively prevented, provided the right proportions were exactly hit. About 3 atoms of Silex to one of lead is I believe as much as the lead will take up to retain its fusibility. When fully saturated it produces a frothy fritting mass - not glass.

Yours truly | J.F.W. Herschel

P.S. The following rather neat process for <<separat>>ing uranium from iron fell in my way in the analysis of some [word illegible] & perhaps may be interesting to you. Dissolve the Prussiates in Carbonate of Potash, which takes them up readily[.] Pour in Caustic Potash. The Uranium precipitates in a yellow Hydrate. The whole of the Iron is retained. It cannot be used for quantitative analysis as a little uranium also is retained in solution, but what falls seems to be of perfect purity².