31 Sackville S^t<1>

Dear Sir

I have been experimenting today with M^r Pearsall^<3> after one or two little detonations of our oxygen, which we corrected by using alcohol mixed with water, we obtained a combustion apparently without light. But on removing the lamp into a dark room, we proved the existence of an internal flame, pointing <illegible deletion> downward and touching the surface of the alcohol. Why this flame does not ignite the cotton wire, I cannot tell. You had better therefore return the paper I sent you, & I will send something else instead of it, for the Journal of the R. Inst^n<4>

I observed today the rather a curious phenomenon which enables one to distinguish at once the Ammoniuret of Copper, from the Ammonio Nitrate of Nickel, both of which you have in the Laboratory. Both are blue by daylight & almost of the same tint, but look at a red hot coal thro the Nickel & you will see it Red, but thro’ the Copper and you will see it blue.^<5>

Yours truly

H. F. Talbot

1. 31 Sackville Street, London residence of the Feildings, often used as a London base by WHFT.

2. ‘March 1832’ added in Faraday’s hand.

3. Thomas J. Pearsall (1805–1883), Laboratory Assistant in the Royal Institution from 1827–1832.

4. Royal Institution, London.

5. See WHFT’s ms notebook I, entry for 29 March 1832, f.96.