[the letter is in the NMM and its envelope in the BL]
Dear Sir,
Many thanks for your Letters and their details <1> which I have made the best use of I can.
I have said nothing in relation to Arago’s remark in the Comptes Rendus, <2> as the discussion of the subject cd do no good. I have considered it unquestionable & unquestioned that you are the sole Author of the Calotype as Daguerre <3> is of the Daguerreotype.
I have been lately making experiments on the transference of Images from Calotypes on to Glass. I have taken beautiful impressions on Glass. When from a Positive the Reflected Picture produced by breathing is positive and the neg transmitted one negative. My theory of this class of phenomena, and I would almost venture to say of those discovered by Moser <4> is that vapour from the Picture is taken into the Pores of the Glass or Metallic surface. In my results I am confident of this fact; I have this moment been trying by the friction of Shamois leather to efface the Picture from the Glass; but it persists, and rubbing will reverse it by rubbing into the pores other matter, or dissolving the absorbed vapour. This fully explains the celebrated Cameo Expt of Moser, the white part having absorbed a difft quantity of oil from the black part.
I am Dear Sir Ever most truly yrs
D Brewster
St Leonards College
St Andrews
Novr 18th 1842
[envelope:]
Henry Fox Talbot Esqr
39 Sackville Street
London
Laycock Abbey
Chippenham
Wilts
Notes:
1. See Doc. No: 04638.
2. Dominique François Jean Arago, ‘Fixation des images de la chambre obscure’, Comptes Rendus hebdomadaires des séances de l’ de l’Académie des Sciences, v. 8 no.6, 11 February 1839, pp. 207–208. Arago, without seeing WHFT's results, concluded that he was mistaken in declaring priority for the invention of photogenic drawing, and that WHFT's work was merely an imitation of that of Daguerre and Joseph Nicéphore Niépce. This ill-informed declaration would have been painful for Brewster, for Arago and WHFT were both long-standing close friends.
3. Louis Jacques Mandé Daguerre (1787–1851), French artist, showman & inventor.
4. See Doc. No: 04541. Ludwig Ferdinand Moser (1805–1880), ‘Ueber den Process des Sehens und die Wirkung des Lichts auf alle Körper’, Annalen der Physik und Chemie, v. 56 no.6, 1842, pp. 177–234.