Correspondence map
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John Frederick William Herschel
Hans Christian Oersted
John Frederick William Herschel invents the actinometer to measure the heating power of the Sun’s rays
1825

Autograph letter signed by sender. Apologizes for the long delay in writing of John Frederick William Herschel's election into the Danish Royal Academy of Sciences. Hans Christian Oersted is carrying on experiments with chlorine gas and metals.
24 July 1825 Sender: Hans Christian Oersted Reference number: HS/13/162John Frederick William Herschel publishes in the Philosophical Transactions
1826:
John Frederick William Herschel publishes “On the parallax of the fixed stars”.

Copy of a letter. Thanks Hans Christian Oersted for John Frederick William Herschel's election to the Royal Academy of Copenhagen. Comments on some chemical and magnetical experiments.
1826 Sender: John Frederick William Herschel Reference number: HS/20/228Joseph Nicéphore Niépce presents his photographs in England for the first time
1827
John 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
Mary 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
Birth 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
Sir 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.
Sir 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. This letter will be delivered by Prof. [C. A.?] Jensen of the Royal Danish Academy of Fine Arts, a distinguished painter. Would like him to paint a portrait of John Frederick William Herschel if agreeable.
26 April 1839 Sender: Hans Christian Oersted Reference number: HS/13/163
Autograph letter signed by sender. Recommending Capt. Zahrtman of the Royal Danish Navy. Hopes to hear good news of John Frederick William Herschel.
4 June 1839 Sender: Hans Christian Oersted Reference number: HS/13/164
Copy of a letter. Apologizes for having been too busy to sit for a portrait as proposed, thanks Hans Christian Oersted for his poems, and describes John Frederick William Herschel's current experiments related to photography.
29 July 1839 Sender: John Frederick William Herschel Reference number: HS/22/21Sir 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”

Copy of a letter. Offers Hans Christian Oersted a small requiem, which John Frederick William Herschel's family sung at the beginning of the astronomical year at the memorial of the 40-foot reflector.
28 January 1840 Sender: John Frederick William Herschel Reference number: HS/22/57Sir 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. Will be receiving the official news soon that John Frederick William Herschel has been nominated Knight Commander of the Order of Dannebrogg. New magnetic observatory to replace the old one. Is grateful for John Frederick William Herschel's excellent song about the telescope.
11 June 1841 Sender: Hans Christian Oersted Reference number: HS/13/165
Autograph letter signed by sender. Explaining how John Frederick William Herschel may express his thanks at being made a Knight Commander. Hans Christian Oersted has also been made a Knight Commander. Will see that he now spells his name Ørsted.
4 July 1841 Sender: Hans Christian Oersted Reference number: HS/13/166
Autograph letter signed by sender. Glad to inform John Frederick William Herschel that there are no fees or expenses involved in being made a Knight Commander. Has had little leisure himself for scientific pursuits due to being Rector of the University.
16 November 1841 Sender: Hans Christian Oersted Reference number: HS/13/167
Copy of a letter. Expresses his great appreciation for informing John Frederick William Herschel of the honor being conferred by making John Frederick William Herschel a Knight Commander of the ancient and venerable order of Danneborg.
20 June 1841 Sender: John Frederick William Herschel Reference number: HS/22/88
Copy of a letter. Asks Hans Christian Oersted if he can discover, without mentioning John Frederick William Herschel's name, what it might cost John Frederick William Herschel to be formally enrolled in Denmark for the honor he has received [see John Frederick William Herschel's 1841-6-20].
10 October 1841 Sender: John Frederick William Herschel Reference number: HS/22/98
Copy of a letter. Thanks Hans Christian Oersted for his effort on John Frederick William Herschel's behalf [see John Frederick William Herschel's 1841-10-10], and then describes some of his photographic experiments.
4 December 1841 Sender: John Frederick William Herschel Reference number: HS/22/102Birth 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”
Birth of Matilda Rose Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1844
Sir 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

Draft Letter, signed by sender. Printed notice of thanks for memoir presented by John Frederick William Herschel.
20 March 1846 Sender: Hans Christian Oersted Reference number: HS/13/168
Autograph letter signed by sender. Sending a German translation of an unfinished work of Hans Christian Oersted. Regrets that so few people can read the Danish language. Is grateful for John Frederick William Herschel's papers.
8 April 1846 Sender: Hans Christian Oersted Reference number: HS/13/169Sir 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. Sends two of his papers. R. I. Murchison has now received the Order of Dannebrogg. If John Frederick William Herschel thinks he can utilize the order once conferred on him he should write to the King. P.S. King is now dead, but could pass the letter to the appropriate body.
20 June 1847 Sender: Hans Christian Oersted Reference number: HS/13/170The 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
Sir John Herschel publishes Outlines of Astronomy.
1849

Autograph letter signed by sender. Has not heard from him for a long time or his letter was not delivered and the unrest in Europe has not encouraged him to write letters. Sends articles, also part of a book, which he has been trying to get published by an English publisher. Would like the advice of John Frederick William Herschel on this effort.
29 August 1849 Sender: Hans Christian Oersted Reference number: HS/13/171
Autograph letter signed by sender. Thanks for promise of kind intervention on his behalf, but he believes that John Frederick William Herschel would not advise him to publish the work in England. Thinks it would be more welcome in Germany. Would like comments and corrections.
12 October 1849 Sender: Hans Christian Oersted Reference number: HS/13/172