651
Algiers, of San Fernando, Tacubaya, of Santiago, of
Plata, Rio de Janeiro, of the Cape, of Sydney and fi -
nally Melbourne. With these three congresses, several
provisions were adopted. They agreed on certain points
among which were the dimensions of the objectives,
focal distances, sizes of the plates, the maximum size
of stars to be recorded, the reproduction of stereotypes
intended to fi ght against the accidental damage, their
conservation, as well as the measuring apparatus allow-
ing the examination a posteriori.
Despite everything, these provisions and the schedule
of conditions of the recommendations discussed was
interminable, obliging the majority of the observatories
to defer the project. The exorbitant cost of the opera-
tion also slowed down the enthusiasm of some of them.
On the eve before of the First World War, only the ob-
servatories of Paris, Toulouse, and Algiers had partly
completed work. At the same time, other astronomical
fi elds of research appeared, relegating the sky chart to
the secondary row of concern. Three quarters of a cen-
tury after its launching, at the General meeting of the
International Astronomical Union held in Brighton in
1970, the project of photographic chart of the sky was
defi nitively abandoned. In spite of this failure, never
had the affi rmation of an offi cial and systematic use of
photography been so strong.
The reputation of the Henry brothers, which is not due
to any spectacular discovery as it is to scientifi c logic,
fi nds legitimacy in the decisive part that they played in
the establishment of this photographic chart of the Sky
and more largely in the history of French astronomical
photography.
On July 25, 1903, Prosper, younger of the two brothers,
died in a climbing accident that occurred in the climbing
station of Pralognan in Savoie. Two years later, January 4,
1905, Paul died in Montrouge on the outskirts of Paris.
Denis Canguilhem
Further Reading
Weimer, Théo, Brève Histoire de la carte du ciel en France, Paris:
Observatoire de Paris, 1987.
Dictionary of Scientifi c Biography, vol. 6, New York: Charles
Scribner’s & Sons, 1981.
Bajac, Quentin et al., Dans le Champ des Etoiles. Les Photog-
raphes et le Ciel 1850-2000, Paris: Musée d’Orsay, 2000
(exhibition catalogue).
Vaucouleurs, Gérard de, La Photographie Astronomique, Paris:
Albin Michel, 1958.
Mouchez, E., La photographie astronomique à l’observatoire de
Paris, Paris: Gauthier-Villars, 1897.
HENSCHEL, ALBERT (1827–1882)
German-born, Brazilian photographer
Albert (Alberto) Henschel was born in Germany on
June 13, 1827, to Helene Henschel and Moritz Hen-
schel, a successful engraver based in Berlin. By the
time Albert arrived in Recife, Pernambuco, Brazil, in
1866 together with business partner Karl Heinrich Gut-
zlaff, he was an experienced photographer. Henschel
later opened studios in Bahia, Rio and São Paulo. Wil-
helm (Guilherme) Gaensly worked as his assistant at
the “Photographia Allemã” studio in Salvador, Bahia.
In the early 1870s, Henschel formed a partnership with
fellow German Francisco Benque and on December
7, 1874, Henschel & Benque became Photographers
to the Imperial House in Rio. Henschel is best known
for his cartes-de visite and landscapes taken in Rio
de Janeiro Province. Noted for their respectful por-
trayals of their subjects, his portraits of African and
Creole slaves and freedpersons belonged to a series of
about 40 taken in Recife, Salvador and Rio. Henschel
participated in several Brazilian exhibitions and won
a medal of merit at the Vienna Universal Exhibition
of 1873. He died in Rio on June 30, 1882. His works
are housed at the Leibniz-Institut Für Länderkunde,
Leipzig (Germany) and the Emanoel Araújo Collec-
tion, the Moreira Salles Institute and the Joaquim
Nabuco Foundation (Brazil).
Sabrina GledhillHENTSCHEL, CARL (1864–1930)
English photographer
Carl Hentschel founded his fi rm of photo-engravers,
designers, electrotypers and stereotypers in 1887 and
there were premises in London, Manchester and Liver-
pool. The fi rm advertised that it was the largest fi rm of
photo-engravers in the world.
Hentschel was born in Lodz, in Poland on 27th
March, 1864 and emigrated to England with his parents
at the age of fi ve. He served his apprenticeship with his
father and initially worked using the ‘photo-on-wood’
process.
Hentschel’s reputation lies in his invention of the fi rst
photomechanical process block to bring about a revolu-
tion in half-tone newspaper illustration. However, Hent-
schel was also involved in book illustration such as the
photomechanical reproduction of Aubrey Beardsley’s
compositions for Oscar Wilde’s Salome (1894) and those
he created of photo-micrographs for Lennox Browne’s
Diphtheria and its associates published in 1895.
Carl Hentschel Colortype Company formed in 1899
and exploited a three-colour printing process based on
colour-separation onto monochromatic plates. Beatrix
Potter’s fi rst book, Peter Rabbit, published in 1902, was,
at the author’s suggestion, printed using this process.
Hentschel was closely linked to the London theatrical
world and was founder of the O.P. Club. The character