Faraday to Mary Somerville   12 October 1835

Royal Institution | 12 Oct 1835

Dear Mrs. Somerville

I have been making some experiments with the papers but do not succeed in obtaining so good & regular a result as I wished & believed I might obtain¹[.]

In the first place the precipitates made upon the paper are not so sensible or regular as that first found & washed & applied in the normal way the excess of the muriate or nitrate used & the resulting salt formed interfering with action of light by retarding more or less the change and that in an irregular manner[.] Chloride produced on the paper is therefore nothing like so regular in its change as chloride previously precipitated & well washed[.]

In the next place I do not find that I can lay a more regular coat of the substance on the method I mentioned than by using the moist precipitated chloride & a camel hair pencil[.]

I suspect your chloride is a good deal discovered[.] I will therefore precipitate & wash some and send it to you in the moist state[.] Allow me to suggest that when you refer to and apply it to paper for your experiments you do so in a dark place or by candle light only & then you may keep it for a long time in good condition[.]

I send also Biots report for your inspection²[.]

Every Your faithful Servant | M. Faraday

Mrs. Somerville