"The Abbe de la Caille," as he was later to become,
laid the foundations of Southern Hemisphere astronomy. He was the predecessor
of all the later pioneers such as Maclear,
It has sometimes been suggested that La Caille's achievements were largely
vitiated by the lack of adequate instrumentation for his basic work, but
a scientist of the stature of Sir Thomas Maclear did not think so and
neither did Sir John Herschel, whose survey of the southern sky
is now generally held by astronomers to have been the true starting-point
of modern scientific work in this field. Had La Caille been able
to use modern-type instruments as well, his work would have advanced
our knowledge of southern-hemisphere astronomy by almost a hundred
years. As it was, he showed later generations how to set about an intensive
observing programme and his diligence in pursuing it, has become
legendary. It is not from pure sentiment that a piece of charcoal from
one of his signal fires is preserved at the Cape Observatory to
this day. With several excellent works on mathematics and astronomy
to his credit, La Caille was singled out. It was because of his proven
competence and wide knowledge that when he later made an error in one
of his major geodetic measurements (Arc
of the Meridian),
men of the calibre of Maclear and Herschel went to enormous lengths
to discover how the calculations of such an expert could possibly
have gone wrong. Establish the cause of La Caille's mistake, they reasoned
and an important scientific principle could be unearthed. They were right.
[Copied Moore, pp. 29 - 31.]
Sir George Everest, Surveyor General of India (after whom
the highest mountain in the world was named and who had many experiences
with the effect of mountains on surveys), came to South Africa and
inspected La Caille's work. He realised the mistake that La Caille
made, but it was left to Maclear to prove it. [Amod, p. 3]
Lacaille received formal classical education & the religious
title of Abbe was conferred upon him when he completed his studies. He
did not pursue a career in religion.
Jacques Cassini of University of Bologna's Observatory employed
Lacaille to survey the French coast from Nantes to Bayonne. He did
an impressive job!
In 1739 Jacques Cassini employed Lacaille to re-measure the
French arc of Meridian. (This was important to determine the size &
shape of the earth). He did an impressive job.
The excellent work that that he did on the survey of the coastline
& arc of meridian got Lacaille admitted to the French Academy
of Sciences. He was appointed the chair of Mathematics at Mazarin College
(now Institute of France). Here a small observatory was established
The French Academy of Science decided to send an expedition to the
Southern Hemisphere. Lacaille was chosen in 1750.
Duties at Cape Town:
Measured the Earth-Mars distance: and Lacaille arrived at value
equal to 131 500 000 km (81 710 310 mile). [Koorts; MNASSA, April 2004,
-Measure an arc of Meridian to prove the earth's shape is
oblate (flattened at the Poles)
-To establish exact longitude at the Cape
-Provide a reliable catalogue of the Southern stars to aid
-Magnetic variation studies
-Measure distances to moon & closer planets.
Lacaille arrived at Cape Town on the 19th of April 1751 [Forbes]
Lacaille's achievements while in Cape Town:
Chartered positions of almost 10 000 stars (9 766),
grading them according to brightness. (Stoy, p.412.)
Catalogue of Nebulae. In 1755 he dispatched to French Army
a catalogue of 42 nebulaes.
Daily record of weather & tides.
Regular magnetic observations.
Fixed longitude of Cape by using observations of the satellites
Measured height of Table Mountain. (Stoy, p.414.)
He drew up a number of constellations & named them.
Some of the constellations are still in use today. Titles are in
a shortened form. "
Instead of the classical nomenclature of mythology, he used scientific
instruments as the inspiration for his new titles.
Thus we have:
-Apparatus Sculptoris (the Sculptor's Tools)
-Fornax Chemica (the Chemical Furnace)
-Horologium (the Clock)
-Reticulus Rhomboidalis (the Rhomboidal Net)
-Caela Sculptoris (the Sculptor's Chisel)
-Equuleus Pictoris (the Painter's Easel)
-Pyxis Nautica (the Mariner's Compass)
-Antlia Pneumatica (the Air-Pump)
-Octans (the Octant)
-Circinus (the Compasses)
-Norma, alias Quadrans Euclidus' (Euclid's Square)
-Telescopium (the Telescope)
-Microscopium (the Microscope)
-Mons Mensae (Table Mountain)" [Copied from Moore, p. .37.]
Measured the Arc
at Cape Town. He did painstakingly exact work and the results proved the
earth to be pear shaped, i.e. round at the top and bulge out in the bottom
* (The arc of Meridian is important to determine the size &
shape of the earth. Scientists knew from measurements & Newton's
theory of gravity that the earth is round and a bit flattened at
the Poles). It took a scientist of equal repute i.e. Herschell & Maclear
to discover the mistake Lacaille made. [The story concerning the
Arc of Meridian is to be found under the section Projects ]
"A subsequent check also showed that the tape he had used, was in
error by nearly 10 cm." [Copied from Smits]
After Cape Town:
Lacaille left the Cape on 8th of March 1753 for Mauritius
& later returned to France where he went back to the Mazarin College.
Lacaille deduced a number of important results from his trip
to the Southern Hemisphere. His contributions to science were against
the most valuable of 18th Century.
Religious title Abbe conferred onto Lacaille.
Measured coastline of France.
1739: Measured Arc of Meridian in France.
Lecturer in Mathematics at Mazarin College in France
1751: Sent to Cape Town to measure the Arc of the Meridian
in the Southern Hemisphere.
1753 (08 March): He left Cape Town for Mauritius
Lecturer at Mazarin College.
Born 1713 in Rumingy, Ardennes, not far from the Cathedral City of
Died 1762 (Age 48)
Address: Erected an observatory in the courtyard of the
residence of Jan Laurens Bestbier, 7 Strand Street, Cape Town.
Several other prominent visitors also stayed here.
Photo of House [Moore p. 35, p. 40; Smits]
Plaque: Designed by Sir Herbert Baker. Located in Cape Town Station?
Tape for measurement (Whereabouts?)
"A subsequent check also showed that the tape he had used, was in
error by nearly 10 cm." [Copied from Smits
Piece of coal from a fire made by Lacaille kept at the Cape Observatory
[Warner – Astronomers, p.50.]
Painting of Abbe De La Caille. (South African Library) [Moore p. 28.]
Two sketches by C. Piazzi Smyth of La Caille's northern point. (South
African Library) [Moore pp. 60 - 61.]
A, et.al., A History of Geodetic Surveying in South Africa - Part
1, The Cape Odyssey, Historical Media cc, Cape Town, Aug./Sept. 2002
- Vol. 2 Issue 7, pp. 1 - 9.
S., Some Scientific Matters in Early Writings on the Cape, A History
of Scientific Endeavour in South Africa, Royal Society of South Africa,
- Glass, I.S.: “Nicolas-Louis de la Caille, Astronomer and Geodesist”, Oxford University Press, 2012. ISBN 978-0-19-966840-3
W.: The 1882 transit of Venus: The British expeditions to South Africa;
MNASSA April 2004, Vol. 63 nos. 3 & 4, pp. 34 - 57.
P. & Collins, P., Astronomy in Southern Africa, pp.28 - 43.
P. A Brief History of Astronomy in Southern Africa. (Unpublished).
- Stoy, R.H. Astronomy in South Africa, pp.409 - 426.
B., Astronomers at the Royal Observatory Cape of Good Hope.
De La Caille:
Notebook: University of Witwatersrand have a notebook.
Astronomae Fundamenta (Africana Museum)
Journal Historique: 1763 (SA Library)
Coelum australe stelliferum (Paris, 1763).
Book based on his work published by British Astronomers after his death:
A catalogue of 9766 stars in the Southern Hemisphere: from the observations
of the Abbe de la Caille: 1847.
THE LIBRARY, UNIVERSITY OF WITWATERSRAND, JOHANNESBURG [JHA
-Lacaille's working notebook 1746-54 (Ref. A892) contains observations
made at the Cape from 1751 April 19 to 1753 March 8. Also observations
made elsewhere and a list of expenses in connection with his observatory
at St Martin (Paris) in 1748. The results of his Cape observations
were published in Coelum australe stelliferum (Paris, 1763).
SOUTH AFRICAN PUBLIC LIBRARY, CAPE TOWN [JHA8, p. 220.]
-Lacaille: Letter 1754 August 20 to M. de la Condamine, reporting
on his astronomical observations at the Cape (see Quarterly bulletin of
the South African Library, vii (1952), 3-7).
-Lacaille: Historical journal of the voyage made to the Cape of
Good Hope (1750-53): typescript translation by Mrs E. Melck. Accompanied
by Notes and reflections upon Kolbe's work, by Lacaille.
SOUTH AFRICAN ARCHIVES, ROELAND STREET, CAPE TOWN [JHA8, p. 220.]
This is the principal depository for all the early Government records
and thus contains official correspondence concerning the visits of Kolbe
SOUTH AFRICAN ARCHIVES, ROELAND STREET, CAPE TOWN [JHA8, pp. 220 - 221.]
Maclear - Mann Papers (Accession No. 515): This extensive accumulation
of manuscripts and correspondence are contained in 139 files. They
derive from presentations made by members of the Maclear family and from
donations from the Trigonometric Survey and from the Royal Observatory,
Cape. Although mostly concerning Sir Thomas Maclear and William Mann,
a considerable amount of material relate to Sir John Herschel and to the
early history of the Cape Observatory. Excluding miscellaneous files
of accounts, testimonials, newspaper cuttings, etc., the most significant
Files 129 Fallows's observing books 1822-23. Copies of observations
1823- 24, 1828, 1829-31.