Baden Powell
John Frederick William Herschel
John Frederick William Herschel invents the actinometer to measure the heating power of the Sun’s rays
1825

Autograph letter signed by sender. Missed John Frederick William Herschel at the Royal Society [of London] meeting. Has some experiments on which he seeks John Frederick William Herschel's opinion regarding presentation at the Society. Enclosing report.
18 November 1825 Sender: Baden Powell Reference number: HS/14/47John Frederick William Herschel publishes in the Philosophical Transactions
1826:
John Frederick William Herschel publishes “On the parallax of the fixed stars”.
Joseph 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
Sir 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”
Sir Robert Peel becomes Prime Minister
1841
Birth of Amelia Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1841
Birth 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
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.
The 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
Sir John Herschel is appointed Master of the Mint
1850
Sir John Herschel serves as juror of the Great Exhibition
1851
Birth of Constance Anne Herschel, daughter of John Frederick William Herschel and Margaret Brodie Stewart
1855
Sir John Herschel is elected Foreign Associate of the Institut de France
1855
Sir John Herschel resigns from his position as Master of the Mint
1855

Autograph letter signed by sender. Regrets letter read the night before at the Royal Astronomical Society of John Frederick William Herschel's wish to resign and hopes John Frederick William Herschel's health allows him to come occasionally and be a nominal member. Discusses Piazzi Smyth's preparations for voyage to Teneriffe.
14 June 1856 Sender: Baden Powell Reference number: HS/14/48
Autograph letter signed by sender. Regarding John Frederick William Herschel's question about formulae for intensities of reflected light, BP encloses a paper concerning G. G. Stokes's conclusions about the direction of the plane of vibrations.
16 November 1859 Sender: Baden Powell Reference number: HS/14/49Sir John Herschel publishes in the Proceedings of the Royal Society
1860: Sir John Herschel publishes some “Remarks on colour-blindness" extracted from a referee report on Pole’s paper on the same subject.
