Correspondence map
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John Frederick William Herschel
William Henry Fox Talbot
Death of Sir William Herschel FRS
25 August 1822

Copy of a letter. John Frederick William Herschel gave passport to commander or steward with instructions to use it to retrieve mail forwarded to John Frederick William Herschel in Calais. Lack of response concerns John Frederick William Herschel. Please procure mail and send it with John Frederick William Herschel's passport to 9 Downing St. Reward.
4? September 1822 Sender: John Frederick William Herschel Reference number: HS/19/34John Frederick William Herschel receives the Bakerian Medal of the Royal Society.
1823:
John Frederick William Herschel gives the Bakerian lecture “On certain Motions produced in Fluid Conductors when transmitting the Electric Current”.
John Frederick William Herschel moves to 56 Devonshire St., Portland Place, London
1824
John Frederick William Herschel serves as Secretary of the Royal Society
30 November 1824
John Frederick William Herschel invents the actinometer to measure the heating power of the Sun’s rays
1825
John Frederick William Herschel publishes in the Philosophical Transactions
1826:
John Frederick William Herschel publishes “On the parallax of the fixed stars”.

Autograph letter signed by sender, incomplete. Asks John Frederick William Herschel about Dr. Balfour's account in Asiatic Researches about lunar effects on humans in India.
4 January 1826 Sender: William Henry Fox Talbot Reference number: HS/17/257
Autograph letter signed by sender. Comments on use of muriate of lime on plants. Also on existence of unexplained bands on film and on presence of red light beyond normal spectrum with light originating from certain sources.
12 January 1826 Sender: William Henry Fox Talbot Reference number: HS/17/258
Autograph letter signed by sender. Comments on Josef Fraunhofer's work on double stars, on quality and color of light from different sources, refraction of different kinds of light, and solution of a problem in conic sections. Is going to Geneva and Modena soon.
27 February 1826 Sender: William Henry Fox Talbot Reference number: HS/17/259
Autograph letter signed by sender. Describes observations made as he travelled and people visited on journey from London to Ancona.
24 March 1826 Sender: William Henry Fox Talbot Reference number: HS/17/260
Autograph letter signed by sender. Talks about Josef Fraunhofer's failing health and his making of flint glass.
1826-7 Sender: William Henry Fox Talbot Reference number: HS/17/261
Autograph letter signed by sender. Is sending on two items directed to John Frederick William Herschel through William Henry Fox Talbot.
24 August 1826 Sender: William Henry Fox Talbot Reference number: HS/17/262
Autograph letter signed by sender. Questions and comments regarding improvements in microscopy.
28 January 1826? Sender: William Henry Fox Talbot Reference number: HS/17/323
Autograph letter signed by sender. Comments on several experiments with spectra passing through glass films.
1826-1 Sender: William Henry Fox Talbot Reference number: HS/17/324Joseph Nicéphore Niépce presents his photographs in England for the first time
1827

Autograph letter signed by sender. Describes prismatic spectrum of flame of cyanogen and offers to repeat experiment with Michael Faraday for John Frederick William Herschel's benefit.
22 May 1827 Sender: William Henry Fox Talbot Reference number: HS/17/263
Autograph letter signed by sender. Asks John Frederick William Herschel to clarify what goods are his from a joint order with William Henry Fox Talbot from a German optical firm.
3 July 1827 Sender: William Henry Fox Talbot Reference number: HS/17/264
Autograph letter signed by sender. Queries and comments about telescopes and microscopes; some thoughts about a diffraction grating.
18 July 1827 Sender: William Henry Fox Talbot Reference number: HS/17/265
Autograph letter signed by sender. Renders an accounting of expenses for optical goods received from Germany.
8 August 1827 Sender: William Henry Fox Talbot Reference number: HS/17/266
Autograph letter signed by sender. Writes in favour of a London University professorship for Thomas Key. Refers to some optical experiments of Michael Faraday, and extends solution of conic section problem first raised in William Henry Fox Talbot's letter of 1826-2-27.
29 October 1827 Sender: William Henry Fox Talbot Reference number: HS/17/267John Frederick William Herschel and Margaret Brodie Stewart are married in London
3 March 1829
John Frederick William Herschel is elected Foreign correspondent of the Académie des sciences
1830
Birth of Caroline Emilia Mary Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
31 March 1830
John Frederick William Herschel is nominated for the presidency of the Royal Society, loses by 8 votes to the Duke of Sussex
30 November 1830

Contemporary copy in sender's hand, signed by sender. Signing certificates for election to fellowship in the Royal Society [of London] at this time [John Frederick William Herschel having been nominated for President] would be very awkward for John Frederick William Herschel, so he will not sign for William Henry Fox Talbot.
28 December 1830 Sender: John Frederick William Herschel Reference number: HS/25/1/15Mary Somerville publishes Mechanism of the Heavens
1831
Sir John Herschel is created Knight of the Royal Hanoverian Guelphic Order
1831
Sir John Herschel publishes Preliminary Discourse on the Study of Natural Philosophy as part of Dionysius Lardner’s Cabinet Cyclopaedia.
1831
Birth of Isabella Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
5 June 1831
Sir John Herschel receives the Royal Medal from the Royal Society
1833:
The Medal is awarded "For his paper on nebulae and clusters of stars, published in the Philosophical Transactions for 1833."
Sir John Herschel publishes A treatise on astronomy as part of Dionysius Lardner’s Cabinet Cyclopaedia.
1833
Birth of William James Herschel, son of John Frederick William Herschel and Margaret Brodie Stewart
1833
Sir John Herschel departs for South Africa with his wife and their three children
13 November 1833

Autograph letter signed by sender. Asks about rumor regarding John Frederick William Herschel going to Cape. Describes some electrical experiments William Henry Fox Talbot saw at Royal Institution and refers to some William Henry Fox Talbot carried out years earlier.
4 March 1833 Sender: William Henry Fox Talbot Reference number: HS/17/268
Autograph letter signed by sender. Asks for seeds and roots of native plants of the Cape. Refers to John Frederick William Herschel's writings on beating of the heart and comments on some optical experiments of Charles Wheatstone and David Brewster.
9 March 1833 Sender: William Henry Fox Talbot Reference number: HS/17/269
Autograph letter signed by sender. Comments on John Frederick William Herschel's paper on potash in Annales de chimie. Has observed reaction products in microscope. Concerned over delay in publication by David Brewster of his experimental results in optics and light, especially as William Henry Fox Talbot not convinced of legitimacy of rumored results.
27 March 1833 Sender: William Henry Fox Talbot Reference number: HS/17/270
Autograph letter signed by sender. Has performed some Newton's rings interference experiments. Asks whether such experiments have already been communicated to the Royal Society [of London]
28 May 1833 Sender: William Henry Fox Talbot Reference number: HS/17/271
Autograph letter signed by sender. Trying to understand David Brewster's results on absorption of light in gaseous state, and the dark lines in solar spectrum, the cause of which he misunderstands.
31 May 1833 Sender: William Henry Fox Talbot Reference number: HS/17/272Birth of Margaret Louisa Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1834
Sir John Herschel serves as President of the Literary and Philosophical Society of the Cape of Good Hope
1835
Halley’s comet becomes visible
28 November 1835
Birth of Alexander Stewart Herschel, son of John Frederick William Herschel and Margaret Brodie Stewart
5 February 1836
Victoria becomes Queen of the United Kingdom
20 June 1837
Birth of John Herschel, son of John Frederick William Herschel and Margaret Brodie Stewart
29 October 1837

Autograph letter signed by sender. About plant seeds sent by John Frederick William Herschel from the Cape, William Henry Fox Talbot having sent him some Mexican seeds in return. Halley's Comet only clearly seen on two nights.
27 August 1837 Sender: William Henry Fox Talbot Reference number: HS/17/273Sir John Herschel returns from South Africa
1838: A banquet in presence of Queen Victoria is given to celebrate his return to Britain and made a Baronet.

Autograph letter signed by sender. Writing to welcome John Frederick William Herschel home from the Cape.
23 May 1838 Sender: William Henry Fox Talbot Reference number: HS/17/274
Autograph letter signed by sender. About Cape bulbs and seeds, the new travel by railway from Slough to London, and concern about interest in animal magnetism.
11 June 1838 Sender: William Henry Fox Talbot Reference number: HS/17/275
Autograph letter signed by sender. Thanks for more Cape bulbs.
8 July 1838 Sender: William Henry Fox Talbot Reference number: HS/17/276Sir John Herschel serves his first term as President of the Royal Astronomical Society
1839: to 1841
Birth of Maria Sophia Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1839
William Henry Fox Talbot presents his paper-based photographic process at the Royal Society
1839

Autograph letter signed by sender. Will give a paper on fixing the image formed by the camera obscura to Royal Society [of London] and wants to review it with John Frederick William Herschel first.
25 January 1839 Sender: William Henry Fox Talbot Reference number: HS/17/277
Autograph letter signed by sender. John Frederick William Herschel is indisposed, so William Henry Fox Talbot will come to Slough to review paper [see William Henry Fox Talbot's 1839-1-25]. Asks John Frederick William Herschel about appropriate curve on lenses for camera obscura for 2-foot focus.
28 January 1839 Sender: William Henry Fox Talbot Reference number: HS/17/278
Autograph letter signed by sender. Has received urgent request from Athenaeum to allow them to publish paper on 'Photogenic Drawing' before it is read to Royal Society [of London] in light of announcement of the 'Parisian invention.'
29 January 1839 Sender: William Henry Fox Talbot Reference number: HS/17/279
Draft in John Herschel's hand. Much altered compared to letter sent. [Responding to William Henry Fox Talbot's 1839-1-29], urges William Henry Fox Talbot to find some way of giving at least slightly different papers to R.S.L. and Athenaeum. Comments on process of fixing image, referring to a trial of his own.
30 January 1839 Sender: John Frederick William Herschel Reference number: HS/17/279a
Autograph letter signed by sender. More about paper being published in both the Philosophical Transactions of the Royal Society and Athenaeum.
2 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/280
Autograph letter signed by sender. Questions John Frederick William Herschel's intent to display 'photogenic drawings' to Royal Society [of London]
8 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/281
Draft letter 'much altered' . Considerable comment on procedure for submitting paper to Royal Society [of London] Urges William Henry Fox Talbot to mention John Frederick William Herschel's method of washing with hyposulfite. Comments on some photographic experiments of William Henry Fox Talbot.
9 February 1839 Sender: John Frederick William Herschel Reference number: HS/17/281a
Autograph letter signed by sender. Wants to withhold description of 'developing' process until it is perfected to obviate others using it. Also refers to second process to make 'positive' and 'negative.'
11 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/282
Autograph letter signed by sender. Some comments on John Frederick William Herschel's light and photography experiments, especially effects of different kinds of glass and fixing with ferrocyanate.
14 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/283
Autograph letter signed by sender. Describes mediocre results obtained using ferrocyanate of potash for fixing image. Mentions some other methods, including his favorite, common salt. Asks John Frederick William Herschel to keep these secret.
19 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/284
Autograph letter signed by sender. Finally had success washing with ferrocyanate. Wants to present note of 'his' processes to Royal Society [of London] and so to the world.
20 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/285
Autograph letter signed by sender. Wishes to communicate to J. B. Biot, and so to Academie des sciences, John Frederick William Herschel's two 'beautiful' fixing methods, by hyposulfite and ferrocyanate.
27 February 1839 Sender: William Henry Fox Talbot Reference number: HS/17/286
Autograph letter signed by sender. Enlarges upon his method of using salt as photographic fixer; then asks John Frederick William Herschel to explain the chemistry thereof. Has tried Louis Daguerre's fixing process without success.
1 March 1839 Sender: William Henry Fox Talbot Reference number: HS/17/287
Autograph letter signed by sender. Further chemicals used for fixing, including bromide potash.
15 March 1839 Sender: William Henry Fox Talbot Reference number: HS/17/288
Autograph letter signed by sender. Comments on Louis Daguerre's use of muriatic ether, and encloses a photograph of hand writing.
21 March 1839 Sender: William Henry Fox Talbot Reference number: HS/17/289
Autograph letter signed by sender. Comments on a number of chemicals used in photography, as well as referring to John Frederick William Herschel's process of making 'enlargements.'
28 March 1839 Sender: William Henry Fox Talbot Reference number: HS/17/290
Autograph letter signed by sender. Consists mostly of a transcription of two short notes from J. B. Biot to John Frederick William Herschel by way of William Henry Fox Talbot.
29 March 1839 Sender: William Henry Fox Talbot Reference number: HS/17/291
Autograph letter signed by sender. Sends a sample picture fixed by use of iodine [potash].
10 April 1839 Sender: William Henry Fox Talbot Reference number: HS/17/292
Autograph letter signed by sender. More photography comments. Problems with use of hyposulfite fixer. Superiority of English over Daguerreotype in being able to make copies.
27 April 1839 Sender: William Henry Fox Talbot Reference number: HS/17/293
Draft in John Herschel's hand. John Frederick William Herschel reports his discovery of a highly sensitive paper. Tint continues to deepen with time, as bromine does not. Not prepared to reveal process at present. Is off to Paris.
27 April 1839 Sender: John Frederick William Herschel Reference number: HS/17/293a
Autograph letter signed by sender. Sends John Frederick William Herschel a positive copy and a transparency. Remarks on John Frederick William Herschel's use of muriate of lead and asks John Frederick William Herschel to explain chemistry of it.
2 July 1839 Sender: William Henry Fox Talbot Reference number: HS/17/294
Autograph letter signed by sender. Confused by an 'unfixed' photo from John Frederick William Herschel in which the image shows different effects from different colors of the spectrum. Also other comments on photography.
19 July 1839 Sender: William Henry Fox Talbot Reference number: HS/17/295
Autograph letter signed by sender. Sends some samples of photography made with a solar microscope, and comments briefly on the Daguerreotype.
8 September 1839 Sender: William Henry Fox Talbot Reference number: HS/17/296
Autograph letter signed by sender. Advises John Frederick William Herschel not to publish any new processes in photography as there are patent problems. Comments on the Daguerreotype, and on the difficulty of preserving images in some circumstances.
12 September 1839 Sender: William Henry Fox Talbot Reference number: HS/17/297
Autograph letter signed by sender. Transmits a message from J. B. Biot, comments on the Daguerreotype, although William Henry Fox Talbot has not tried it.
15 November 1839 Sender: William Henry Fox Talbot Reference number: HS/17/298
Autograph letter signed by sender. Comments on many different processes in photography. Still has not tried the Daguerreotype, although William Henry Fox Talbot has had the equipment for a considerable time.
7 December 1839 Sender: William Henry Fox Talbot Reference number: HS/17/299
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. [Responding to William Henry Fox Talbot's 1839-1-29], urges William Henry Fox Talbot to find some way of giving at least slightly different papers to R.S.L. and Athenaeum. Comments on process of fixing image, referring to a trial of his own.
30 January 1839 Sender: John Frederick William Herschel Reference number: HS/22/1
Copy of draft letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Considerable comment on procedure for submitting paper to Royal Society [of London] Urges William Henry Fox Talbot to mention John Frederick William Herschel's method of washing with hyposulfite. Comments on some photographic experiments of William Henry Fox Talbot.
9 February 1839 Sender: John Frederick William Herschel Reference number: HS/22/2
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Comments on several approaches to fixing images on paper, especially using pure water as a fixing agent. Has developed a new sensitive paper but is keeping it secret until perfected. Is leaving for Continent on 1 May.
22 April 1839 Sender: John Frederick William Herschel Reference number: HS/22/11
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. John Frederick William Herschel reports his discovery of a highly sensitive paper. Tint continues to deepen with time, as bromine does not. Not prepared to reveal process at present. Is off to Paris.
27 April 1839 Sender: John Frederick William Herschel Reference number: HS/22/12
Copy letter in John Herschel's hand. John Frederick William Herschel will as William Henry Fox Talbot requests stop mentioning John Frederick William Herschel's hyposulfite fixing process and await publication of William Henry Fox Talbot's process. Reports in detail on some of John Frederick William Herschel's experiments relating to photography and to spectrum analysis. [In a P.S. dated 1839-2-13,] John Frederick William Herschel states: 'I have discovered your secret of fixing [or its] equivalent.'
12 February 1839 Sender: John Frederick William Herschel Reference number: HS/25/5/12
Copy letter in John Herschel's hand. Admires L. J. M. Daguerre's process, but hopes to see paper become dominant medium for photographs. Describes new paper John Frederick William Herschel developed. [Letter continues 6 July.] Experiment with fixed lines in chemical spectra; shows sensitivity of ultraviolet light.
24 June 1839 Sender: John Frederick William Herschel Reference number: HS/25/5/13
Copy letter in John Herschel's hand. Recounts experiments with chemicals, spectra, and photographic paper.
7 July 1839 Sender: John Frederick William Herschel Reference number: HS/25/5/14Sir John Herschel publishes in the Philosophical Transactions
1840: Sir John Herschel publishes “On the chemical action of the rays of the solar spectrum on preparations of silver and other substances, both metallic and non-metallic; and on some photographic processes”

Autograph letter signed by sender. Concerned about the Daguerreotype patent in England, and questions at some length a paper on the origin of freemasonry.
28 February 1840 Sender: William Henry Fox Talbot Reference number: HS/17/300
Autograph letter signed by sender. Waxes lyrical about nature, and comments on a new 'positive' paper John Frederick William Herschel has sent. Refers to John Frederick William Herschel's move to Hawkhurst.
30 April 1840 Sender: William Henry Fox Talbot Reference number: HS/17/301
Autograph letter signed by sender. Sends a few photographs and says he has read John Frederick William Herschel's recent memoir. Will comment later.
15 June 1840 Sender: William Henry Fox Talbot Reference number: HS/17/302
Draft in John Herschel's hand. Sends William Henry Fox Talbot a copy of the solar spectrum in which each color is represented clearly in a 'positive' picture. John Frederick William Herschel sees this as giving hope for color photography.
30 August 1840 Sender: John Frederick William Herschel Reference number: HS/17/302a
Autograph letter signed by sender. Concerned with developing photography for tourist use. Doubts that colors of the spectrum can be readily displayed on photographic paper. The'chemistry' of photography is not understood.
1 September 1840 Sender: William Henry Fox Talbot Reference number: HS/17/303
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Sends William Henry Fox Talbot a copy of the solar spectrum in which each color is represented clearly in a 'positive' picture. John Frederick William Herschel sees this as giving hope for color photography.
30 August 1840 Sender: John Frederick William Herschel Reference number: HS/22/67
Contemporary copy in sender's hand, signed by sender. Tells William Henry Fox Talbot about John Frederick William Herschel developing the thermographic paper which is susceptible to 'calorific' and 'chemical' rays of light.
3 March 1840 Sender: John Frederick William Herschel Reference number: HS/25/6/2Sir Robert Peel becomes Prime Minister
1841
Birth of Amelia Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1841

Autograph letter signed by sender. Announces his invention of the 'calotype', and his application for a patent. Questions John Frederick William Herschel on his address to the Royal Astronomical Society, objecting to idea that universe is infinite.
17 March 1841 Sender: William Henry Fox Talbot Reference number: HS/17/304
Copy letter in John Herschel's hand. Congratulates William Henry Fox Talbot on the calotype invention and the patent. Responds at some length to William Henry Fox Talbot's concerns about the infinity of the universe. In postscript, provides a 4-page dialogue on the subject.
22 March 1841 Sender: John Frederick William Herschel Reference number: HS/17/304a
Autograph letter signed by sender. Preparing his calotype paper for publication. Looking for a summer house, somewhere interesting to photograph.
18 March 1841 Sender: William Henry Fox Talbot Reference number: HS/17/305
Copy letter in John Herschel's hand. A further two dialogues elaborating on John Frederick William Herschel's earlier arguments [see John Frederick William Herschel's 1841-3-18] on the infinity/finitude of the universe.
25 March 1841 Sender: John Frederick William Herschel Reference number: HS/17/305a
Autograph letter signed by sender. Reports receipt of a communication, which argues that all elements are merely isomers of one substance. Expresses support for such a view.
6 April 1841 Sender: William Henry Fox Talbot Reference number: HS/17/306
Copy of letter in John Herschel's hand, with corrections and additions, stained across all pages. Doubts that isomerism of all elements can be verified experimentally, but notes a number of groups with similar atomic weights that might well fit. Further on vegetable colors in photography. Refers to enclosure of a further dialogue on infinity.
6 April 1841 Sender: John Frederick William Herschel Reference number: HS/17/306a
Autograph letter signed by sender. Some details of improvements in the calotype method.
19 May 1841 Sender: William Henry Fox Talbot Reference number: HS/17/307
Autograph letter signed by sender. Sends John Frederick William Herschel sample of chemicals and paper to make calotype himself.
12 June 1841 Sender: William Henry Fox Talbot Reference number: HS/17/308
Autograph letter signed by sender. Has read William Henry Fox Talbot's paper before the Royal Society [of London] and now complains they will not print it in the Philosophical Transactions of the Royal Society as they understand it has appeared elsewhere.
1 July 1841 Sender: William Henry Fox Talbot Reference number: HS/17/309
Draft in John Herschel's hand. Explains the operation of the Council of the R.S.L. and hopes that William Henry Fox Talbot will treat their unintended slight as a 'gaucherie'.
5 July 1841 Sender: John Frederick William Herschel Reference number: HS/17/309a
Autograph letter signed by sender. Reports on paper by Samuel Brown to the Royal Society of Edinburgh on the conversion of carbon to silicon, and other transmutations. Reports on discovery of new element, ozone, and complains further about Royal Society [of London] Council.
25 July 1841 Sender: William Henry Fox Talbot Reference number: HS/17/310
Draft letter. Expresses reservations about Samuel Brown's work. Apologizes for delay in trying calotype; has done only some vegetable substance trials.
1841-7-25 or later Sender: John Frederick William Herschel Reference number: HS/17/310a
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Congratulates William Henry Fox Talbot on the calotype invention and the patent. Responds at some length to William Henry Fox Talbot's concerns about the infinity of the universe. In postscript, provides a 4-page dialogue on the subject.
22 March 1841 Sender: John Frederick William Herschel Reference number: HS/22/81
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. A further two dialogues elaborating on John Frederick William Herschel's earlier arguments [see John Frederick William Herschel's 1841-3-18] on the infinity/finitude of the universe.
25 March 1841 Sender: John Frederick William Herschel Reference number: HS/22/82
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Doubts that isomerism of all elements can be verified experimentally, but notes a number of groups with similar atomic weights that might well fit. Further on vegetable colors in photography. Refers to enclosure of a further dialogue on infinity.
6 April 1841 Sender: John Frederick William Herschel Reference number: HS/22/83
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Explains the operation of the Council of the R.S.L. and hopes that William Henry Fox Talbot will treat their unintended slight as a 'gaucherie'.
5 July 1841 Sender: John Frederick William Herschel Reference number: HS/22/91
Copy of draft letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Expresses reservations about Samuel Brown's work. Apologizes for delay in trying calotype; has done only some vegetable substance trials.
1841-7-25 or later Sender: John Frederick William Herschel Reference number: HS/22/92Birth of Julia Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1842
Sir John Herschel publishes in the Philosophical Transactions
1842: Sir John Herschel publishes “On the action of the rays of the solar spectrum on vegetable colours, and on some new photographic processes”

Autograph letter signed by sender. Sends John Frederick William Herschel samples of his calotypes. Off to Germany on a photographic expedition.
18 April 1842 Sender: William Henry Fox Talbot Reference number: HS/17/311
Autograph letter signed by sender. Carl Steinheil has proposed making telescope mirrors by plating silver on glass. Is writing to John Frederick William Herschel to tell him that somewhat earlier he had included this process in one of his patents.
2 June 1842 Sender: William Henry Fox Talbot Reference number: HS/17/312
Autograph letter signed by sender. John Frederick William Herschel's account of a comet reminds William Henry Fox Talbot of a strange sighting many years ago. Comments further on improvements in photography, both those made and those needed.
22 March 1843 Sender: William Henry Fox Talbot Reference number: HS/17/313
Autograph letter signed by sender. Describes observing of comet that evening.
24 March 1843 Sender: William Henry Fox Talbot Reference number: HS/17/314
Autograph letter signed by sender. Suggests 'amphitype' as name for John Frederick William Herschel's process whereby same picture can go from negative to positive. Further comments on comet sighting, and on some improvements to Daguerreotype.
29 March 1843 Sender: William Henry Fox Talbot Reference number: HS/17/315
Autograph letter signed by sender. Comments on John Frederick William Herschel's positive calotype. Suggests comet may be return of (J.-D.) Cassini's comet of 1668. Gives theorem for finding parabolic orbit of comet if two observations are made in the ecliptic.
5 April 1843 Sender: William Henry Fox Talbot Reference number: HS/17/316
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Comments on confusion between observing comet and zodiacal light. Extensive comments on various materials used in a photographic process where negatives change to positives over long time.
25 March 1843 Sender: John Frederick William Herschel Reference number: HS/22/149
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Zodiacal light is a real phenomenon. Further comments on negative to positive process. Questions whether William Henry Fox Talbot can define one cometary orbit with two observations.
31 March 1843 Sender: John Frederick William Herschel Reference number: HS/22/151Birth of Matilda Rose Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1844

Autograph letter signed by sender. Some comments and questions on mathematics.
8 September 1844 Sender: William Henry Fox Talbot Reference number: HS/17/317
Autograph letter signed by sender. Comments and questions about a 'cone of the second order' in mathematics.
16 September 1844 Sender: William Henry Fox Talbot Reference number: HS/17/318Sir John Herschel serves as President of the British Association
1845
Birth of Francisca Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1846
Sir John Herschel serves his second term as Foreign Secretary of the Royal Astronomical Society
1846: To 1847
Sir John Herschel serves his second term as President of the Royal Astronomical Society
1847: Until 1849
Sir John Herschel receives the Copley Medal
1847: Sir John Herschel receives the Copley Medal of the Royal Society "For his work entitled Results of Astronomical Observations made during the years 1834, 1835, 1836, 1837 and 1838, at the Cape of Good Hope; being a completion of a telescopic survey of the whole surface of the visible heavens, commenced in 1825"
Sir John Herschel publishes a paper
1847: Sir John Herschel publishes Results of astronomical observations made during the years 1834, 5, 6, 7, 8, at the Cape of Good Hope; being a completion of a telescopic survey of the whole surface of the visible heavens, commenced in 1825.

Autograph letter signed by sender. Comments on astronomical symbols, and position of camera when photographing buildings.
26 October 1847 Sender: William Henry Fox Talbot Reference number: HS/17/319The Pre-Raphaelite Brotherhood is formed, by John Everett Millais, Dante Gabriel Rosetti and others
1848
Napoleon III is elected first President of France
20 December 1848

Autograph letter signed by sender. Has performed experiments measuring the deviation of spectra through an obliquely placed diffraction grating. Believes they strongly support the wave theory of light.
4 February 1848 Sender: William Henry Fox Talbot Reference number: HS/17/320
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Refers William Henry Fox Talbot to reference work to check William Henry Fox Talbot's experiments [see William Henry Fox Talbot's 1848-2-4]. John Frederick William Herschel says he will perform no more experiments in physical optics.
29 February 1848 Sender: John Frederick William Herschel Reference number: HS/23/14Sir John Herschel publishes Outlines of Astronomy.
1849
Sir John Herschel is appointed Master of the Mint
1850
Sir John Herschel serves as juror of the Great Exhibition
1851

Autograph letter signed by sender. Refers to process which produces pictures that are negative or positive depending upon the light. Hopes to use it to photograph lunar landscape. Wants to call it 'amphitype' if John Frederick William Herschel agrees.
1851-5-6 or earlier Sender: William Henry Fox Talbot Reference number: HS/17/321
Autograph letter signed by sender. Describes observing solar eclipse at Marienburg in eastern Prussia. Gives advice about whom to see for photography training [see 1851-7-27].
26 August 1851 Sender: William Henry Fox Talbot Reference number: HS/17/322
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Agrees to William Henry Fox Talbot's use of name 'amphitype' [see William Henry Fox Talbot's 1851-5-6 or earlier].
6 May 1851 Sender: John Frederick William Herschel Reference number: HS/23/103
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Wants recommendation from William Henry Fox Talbot for teacher of the 'art of Talbotyping.'
27 July 1851 Sender: John Frederick William Herschel Reference number: HS/23/106
Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Thanks for examples of William Henry Fox Talbot's photographic engraving; sends a photo in return.
14 May 1853 Sender: John Frederick William Herschel Reference number: HS/23/132
Autograph letter signed by sender. Willingly gives John Frederick William Herschel permission to engrave a portrait photograph taken with William Henry Fox Talbot's process. William Henry Fox Talbot asks John Frederick William Herschel if he would be willing to testify on William Henry Fox Talbot's behalf if necessary, relating to infringement of patent rights. William Henry Fox Talbot announces that John Hind has discovered another asteroid [Euterpe].
13 November 1853 Sender: William Henry Fox Talbot Reference number: HS/26/48
Autograph letter signed by sender. Asks John Frederick William Herschel to sign an affidavit that William Henry Fox Talbot is the inventor of the calotype or talbotype as some are trying to break William Henry Fox Talbot's patent hold.
15 May 1854 Sender: William Henry Fox Talbot Reference number: HS/26/49
Autograph letter signed by sender. Sends John Frederick William Herschel a copy of the affidavit [see William Henry Fox Talbot's 1854-5-15] and asks for John Frederick William Herschel's emendations, if any, and his signature. Sends John Frederick William Herschel a photograph engraved on steel.
18 May 1854 Sender: William Henry Fox Talbot Reference number: HS/26/50
Autograph letter signed by sender. Comments on the affidavit supplied by William Henry Fox Talbot; will sign most of it but objects to one section.
19 May 1854 Sender: John Frederick William Herschel Reference number: HS/26/51
Autograph letter signed by sender. Explains the way an affidavit works in the Court of Chancery. Because John Frederick William Herschel feels uncomfortable about certain aspects of the affidavit, William Henry Fox Talbot will not trouble him about it again.
20 May 1854 Sender: William Henry Fox Talbot Reference number: HS/26/52
Autograph letter signed by sender. Clarifies John Frederick William Herschel's position, by saying that he clearly supports William Henry Fox Talbot as the inventor of the calotype or talbotype, but has reservations about the collodion process.
21 May 1854 Sender: John Frederick William Herschel Reference number: HS/26/53
Autograph letter signed by sender. William Henry Fox Talbot's opponents have named John Frederick William Herschel in one of their affidavits against William Henry Fox Talbot. William Henry Fox Talbot is therefore asking John Frederick William Herschel to respond to what is stated in that affidavit.
23 May 1854 Sender: William Henry Fox Talbot Reference number: HS/26/54