TALBOT3838

Q. Ann S^{t 1}
March 15. 1839

Dear Sir

I was sorry not to have heard your paper which I understand was read to the R.S. last night.² – Would you like to send some specimens of your engravings to Baron Humboldt ³ & the Berlin philosophers; – I received a letter from him today & am going to answer it by Tuesday’s post. ⁴ As you told me that you had not quite succeeded in fixing with common salt I enclose a fragment done in that way; and 2 others (yellow) done with iodine. I have found the Bromide of silver very sensitive, & intend saying something respecting it in a paper to the R.S. next week. ⁵ I enclose a scrap, exhibiting 4 different states of the Bromide of which one is nearly invisible (exactly as with the Chloride & iodide) Consequently a stronger solution of Bromide Potash will fix a drawing made with Bromide Silver.⁶ At least I presume that this consequence may legitimately be inferred.

I send a few specimens of this sensitive paper. ⁷ If they have lost their virtue, another wash of nitrate of silver will probably restore it.

Yours most truly
H.F. Talbot