TALBOT4349

S^t Leonards College
S^t Andrews
Oct^r 27^th 1841

Dear Sir,

I write you thus quickly in reply to yours from Tunbridge Wells ¹ to say that Mr Davidson ² makes the most beautiful Portrait Cameras of which we have two here in constant operation. He has supplied all the Reflecting Cameras for the Polytechnic Institution in Regent Street, ³ & he would feel greatly honoured by making one for you. He is an admirable person of real knowledge, and charges less than half of London artists. I think a Portrait Camera about 12 or 13 inches long with two excellent achromatic lenses w^d cost £5 or £6, but this is more a conjecture than a certainty.

I think I must have expressed myself ill in what I said about your new fringes. I of course never thought of telling you that they were the colours of thin plates; – (tho’ by the way they might have been of a diff^t class like those which I have discussed in the Edin. Trans. ⁴ produced by reflection from an achromatic object Glass) but I stated that they were those of thin plates for the purpose of directing you to Sir Isaac Newtons explanation of the very same phenomenon seen under very diff^t circumstances. I did not say or hint that Newton or body [sic] else ever described your Exp^t; but Newton has certainly and clearly explained what you justly consider to be so remarkable, the production of black and white fringes. I am entirely satisfied with Newton’s explanation, but I believe the Undulationists ⁵ will not be able to give any other than that of translating Newton into their own language.

I shall immediately look for the remarkable Red line in Nitrate of Potash &c; but you have not mentioned how the combination is effected in order to produce it.

By the Prism alone without my lens or Telescope I have discovered new lines in the Spectrum, ⁶ of course not by projection as in your Exp^t.

This I think is the headquarters (always excepting Lacock Abbey) of the Talbotype. ⁷ Our Chemical Prof^{r’s 8} Assistant is now at work & successful, so that without counting myself you have three ardent disciples. M^r Furlong, ⁹ the gentleman I allude [to] executed an admirable portrait of a Relation in Ireland which I have seen.

By the way I observe in your Specification that you use ⅓ of acetic acid all your other acc^ts say ¹/₆.

M^r Furlong, like D^r Adamson ¹⁰ has failed in fixing the Positive Talbotype. ¹¹ He does not succeed by washing after the Gallo-nitrate.

I have made some progress in the R.S. affair ¹² I am given to understand that if I will add my observations on atmospheric Polarisation my Paper will be printed. I of course will not add a word. In a few days I will send you the means of Judging in the matter.

I am Dear Sir Ever Most Truly y^rs
D Brewster

H.F. Talbot Esq^r