44 Queen Ann St <1>
Feb. 27th
Dear Sir
Will you allow me to communicate to M. Biot, <2> who will of course mention it to the Académie des Sciences, your two beautiful methods of fixing or washing out, by the hyposulphite & the ferrocyanate? <3>
With respect to the former, I should also wish to add a reference to the work in which you first described the hyposulphuric acid, <4> which I do not exactly know where to find–
Believe me Yours most truly
H. F. Talbot
Sir J. Herschel Bart
Slough
Notes:
1. 44 Queen Ann Street: London home of the Mundy family and a frequent base for WHFT.
2. Jean-Baptiste Biot (1774–1862), French scientist, communicated this to the Academie de Sciences at the meeting of 4 March 1839. Printed in Comptes Rendus hebdomadaires des séances de l’ de l’Académie des Sciences, v. 8 no. 9, pp. 341–342. See Doc. No: 03827.
3. True cyanates do not feature in photographic chemistry, being uncommon and rather unstable. In this case, references to ‘cyanates’ or ‘ferrocyanates’ should be read as meaning ‘cyanides’ or ‘ferrocyanides’. Thiocyanates, also earlier called sulphocyanides, did have some photographic uses.
4. John Frederick William Herschel, ‘On the Hyposulphurous Acid and Its Compounds’, Edinburgh Philosophical Journal, v. 1, 1819, pp.8–19 and pp. 396–400.