Faraday to George Herbert   17 November 1856

Royal Institution | 17. November 1856

My dear Sir

In regard to the three waters Nos. 1. 2 & 3 accompanying your letter of the 12th instant¹, I may report that No.1 is a very good water, of considerable softness,- containing no lead in solution, & therefore in itself wholesome: but on examining the slight deposit in the bottle, lead was found there in small quantity. This is often the case in leaden cisterns:- care should be taken that the pumps or pipes are so arranged not to draw off the deposit in the cistern with the water[.]

No.2. is a good soft water of itself but it contains a little lead in solution. I have explained on former occasions that rain water can dissolve lead, & that whilst the lead remains dissolved the water is unwholesome:- such is the case at present with this specimen.- The little sediment which was there also contained a trace of lead.

No. 3 water is soft & good & there is no trace of lead either in the fluid or the deposit.

All these waters contained small portions of sulphates & chlorides of lime & soda: but as there was nothing objectionable in them but rather an advantage, I have not referred particularly to them[.]

The corks of all the bottles were bad - Bottle No. 3 was also dirty and contained an old wine cork - a dirty cork is competent to affect the lead in water & occasionally to remove it. So that, such a state of things should be avoided in cases where the questions to be considered are important & influential[.]

I am | My dear Sir | Very truly Yours | M. Faraday

G. Herbert Esq | &c &c &c