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When you stand at ground zero, let your mind
travel back in time to the mid-eighteenth century. You are in the
back yard garden of one of the houses on Strand Street. Quite near
to where you are will be a man working at his telescope in the
garden of number 3 Strand Street. It was at this house that the
Abbé Nicolas-Louis de La Caille (often Lacaille) lived and set up
his observatory. He only stayed in Cape Town for two years, from
1751 and 1753.
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The Abbé Nicolas-Louis de La Caille (1713-1762)
Old houses on Strand Street between today’s Aderly St. and
St. Georges Mall, La Caille lived and worked in the house on the
right.
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In this short time, he achieved a monumental
amount of scientific work. He was dispatched to Cape Town by the
French Academy of Sciences to undertake a catalogue of southern
stars, determine the longitude of the Cape, and to measure an arc
of the meridian in the southern hemisphere to better determine the
shape of the earth. He set up a small observatory in the garden of
his residence using a very modest 28 inch telescope with a half
inch aperture. In his short two years at the cape he charted the
positions of almost 10,000 stars, all graded by brightness. He
added and named 14 new constellations. He decided to avoid the
mythical, and name them after scientific and artistic instruments
(such as the telescope, the microscope and Euclid’s Square)
and also he named one after Table Mountain (Mons Mensa). He
identified 42 new nebulae and fixed the longitude of his
observatory using Jupiter’s moons. His measurements of the
Moon and Mars resulted in the most acurate estimated distances for
the Sun and the Moon at the time.
He also undertook extensive field work to
measure a southern arc of the meridian. From his measurements, he
concluded that the southern half of the world was a different shape
than the northern half. He was quite wrong about this, but later
scientists learned a great deal from exactly why he was wrong.
Shortly after completing his arc measurements, La Caille returned
to France. Although he died at the young age of 48, his
contributions to science are among the most valuable made during
the whole of the eighteenth century.
In 1903, to commemorate his achievements, the
South African Philosophical Society (now the Royal Society of South
Africa) designed and erected a plaque to be placed at 3 Strand
Street. There the plaque stayed until the building was demolished
for the Old Mutual Centre in 1973. Four years later the plaque was
displayed inside the center, until a redesign had the plaque moved
outside to the corner of St. George’s Mall and Waterkant St.
Unfortunately, sometime in early March 2010 the plaque was stolen,
presumably for scrap. A smaller plaque, commemorating the moving of
the original in 1977 was also stolen some time after that. You can
see the scars of these two plaques on the building in front of the
cache location. The South African Astronomical Observatory is
making efforts at producing a resin replica to replace these
missing plaques.
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This site has been placed on the tentative
listing of world heritage sites as part of a group of sites
relevant to astronomical heritage at the Cape, and specifically the
recording of the Arc of the Meridian in the southern
hemisphere.
Sources and Further Readings:
Anon. 2009. The Cape Arc of Meridian. UNESCO Tentative
World Heritage Site List Ref.: 5461 (link)
Anon. 2010. Disappearance of Lacille Plaque. Monthly Notes of
the Astronomical Society of Southern Africa, 69:45-46.
(link)
Feast, M. W. 1979. The Abbe de la Caille. Monthly Notes of
the Astronomical Society of Southern Africa, 37:12-14.
(link)
Moore, P. & Collins, P. 1977. The Astronomy of Southern
Africa Robert Hale & Co. London. (link).
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The Memorial Plaque, designed by Sir H. Baker, erected in 1903, now
missing. |