655
cular glass negative 10 centimeters in diameter, made
by percipitating muriate of silver directly onto the glass,
and then washing it with a further wash of silver nitrate.
Herschel marvelled at the clarity and sharpness of the
image, calling the result a “glass daguerreotype.” The
image could be blackened or varnished to enable it to be
viewed as a positive, or “if the varnish be omitted there
seems to be no reason why impressions should not be
taken from it ad infi nitum.”
Although Herschel’s time was increasingly monopo-
lized by the completion of his astronomical catalogues,
he continued to follow up his photochemical experiments
for the next three years. A great part of these experiments
were made with organic compounds, usually the juice
distilled from the petals of fl owers. This particular vein
of research was motivated by his fi rm belief that the
complete spectrum, color for color, could be reproduced
photochemically. Although Herschel ultimately failed to
achieve a workable full- or even multi-colored process,
he saw that photography’s future quite clearly lay in this
direction. In the midst of these color trials, however, he
began a much more fruitful line of enquiry.
Early in 1842, the electro-chemist Alfred Smee
sent Herschel a quantity of the bright red compound
now called potassium ferricyanide. While testing the
sensitivity of this substance under the light of the spec-
trum, Herschel noted that it acted with much the same
sensitivity as guaiacum, and when thrown into water,
it became a deep prussian blue. Smee suggested two
further compounds, Ammonio Citrate and Ammonio
Tartrate of Iron, and by June of 1842, Herschel had
developed both the Chrysotype, named for its use of
gold “to bring about the dormant picture...,” and the
Cyanotype, his most practical and enduring process.
(“On the Action of the Rays of the Solar Spectrum on
Vegetable Colours, and on Some New Photographic
Processes” in Philosophical Transactions of the Royal
Society of London, vol. 132, 1842, 181–214.)
Herschel’s 16 June 1842 paper presented his experi-
ments not as independant inventions of processes, but
as a series of observations on the basic principles of
photographic chemical action. Although he describes
his many experiments, both organic and metallic, he re-
frains from naming them or presenting wholly functional
working processes. It would only be in November of
1842 that he would systematically describe the working
details of his processes. (“On Certain Improvements on
Photographic Processes Described in a Former Com-
munication, and on the Parathermic Rays of the Solar
Spectrum” in Philosophical Transactions of the Royal
Society of London, vol. 133, 1843, 1–6.)
Having contributed, thus, in tens of small ways to
the progress of photography, Herschel’s experiments on
photographic subjects came to a halt in 1843, victims
of his astronomical writing and public duties. But his
interest in photography never ceased. Anna Atkins, a
close friend of the Herschel family, immediately took
up the cyanotype in her self-publishing effort in Botony.
Julia Margaret Cameron declared that Sir John was
‘her fi rst teacher,’ and immortalized him in a series of
portraits. In 1845 Herschel published his fi nal contribu-
tion to photographic research, an observation of what
he called ‘epipolic dispersion.’ George Gabrielle Stokes
would later rename this phenomenon ‘fl ourescence,’ the
study of which led directly to radiation photography of
all types. When Sir John Herschel died in 1871, he was
mourned by a nation, who buried him near Sir Isaac
Newton in Westminster Abbey.
Kelley Wilder
Biography
John Frederick William Herschel was born 7 March
1792 at Observatory House in Slough, near London.
At the age of 24, having already been elected Member
of the Royal Society (1813), he became assistant to his
father, the astronomer Sir William Herschel, and dedi-
cated his life to fi nishing the monumental Herschel star
catalogues. Not only was he respected as an astonomer
and mathematician, he contributed papers on geology,
meterology, chemistry, botony, photography, and edu-
cational reform. He was a talented musician, linguist
and draughtsman, leaving hundreds of camera lucida
drawings. Herschel married Margaret Brodie née Stew-
art in 1828, and they had twelve children. In 1821 and
1847 he was awarded the Copley Medal of the Royal
Society (RS). Herschel was a founding member, and
served as President of the Royal Astronomical Society.
He was, from 1824–1827 Secretary of the RS, and from
1827–1829; 1838–1840; 1847–1848; 1851–1852 Vice
President of the RS. In 1831 he was knighted, and in
1838 made a baronet. He served as Master of the Mint
(1850–1855), as Sir Isaac Newton had before him.
Herschel was the fi rst to publicly utilize photography’s
potential as a scientifi c tool in the study of light, and he
invented numerous photographic processes, among them
the cyanotype and chrysotype in 1842. Herschel died on
11 May 1871 at his house Collingwood, in the village of
Hawkhurst, Kent, where he had moved in 1840.See also: Atkins, Anna; Cameron, Julia Margaret;
Daguerre, Louis-Jacques-Mandé; Hunt, Robert;
Talbot, William Henry Fox; and Cyanotype.Further Reading
Buttmann, Günther, In the Shadow of the Telescope, (Bernard
Pagel trans.), New York: Charles Scribner’s Sons, 1970.
Herschel, John Frederick William, “On the Hyposulphurous Acid
and its Compounds” in Edinburgh Philosophical Journal,
vol. 1, 1819, 8–29.
—–, “Some additional facts relating to the habitudes of the
Hyposulphurous Acid, and its union with Metallic Oxides”