big science and the transits of venus 141
serve the transit from Cape Town. Mason and Dixon were not the only
ones affected by the war. French observer Le Gentil arrived at Pondi-
cherry after months of arduous voyage only to discover that the city had
been occupied by the British. Unable to anchor, his ship had to sail back to
the Indian Ocean, forcing the Frenchman to observe the transit on board
an ocean-bound vessel without the necessary conditions for any scientific
measurements.^14
France and Britain were not the only sponsors of transit expeditions. Nu-
merous intracontinental expeditions participated in the 1761 effort. The
Swedish Academy of Science and the Danish Crown were major sources
for expedition funding.^15 Russia organized two expeditions in addition to
the Franco- Russian Siberia effort mentioned above. France sponsored the
largest number of observers (thirty- one), followed by the Swedes (twenty-
one) and Britain (nineteen). On the whole, at least 120 observers from
eight countries spread over sixty- two stations took part in the 1761 effort
(Woolf 1959 , 141 – 43 ).
The Transit of 1769
The disappointing results of the 1761 observations generated a sense of
urgency in the years leading to the 1769 transit — another missed oppor-
tunity would mean over a century of delay in measuring the astronomical
unit. Members of the British Royal Society called for early preparations
for the upcoming transit: “It behooves us... to profit as much as possible
by the favorable situation of Venus in 1769 , when we may be assured that
several Powers of Europe will again contend which of them shall be most
instrumental in contributing to the solution of this grand problem” (Carter
1995 , 249 ). Although the war had ended in 1763 , international competition
was still an important motivating force.
The Royal Society, not wishing to repeat the hasty preparations of
1761 , started to plan its expeditions in 1766. The main lesson of the 1761
experience was the need to add additional southern stations. While the
relative proximity of the northern polar regions made northern obser-
vations relatively cheap and trouble free, sending an expedition to the
scarcely explored South Sea was a formidable challenge (Woolley 1969 ).
In order to fund its ambitious plans, the Royal Society again appealed for
governmental support. An official memorandum sent to King George III
echoes the same arguments that successfully secured funding for the 1761
expeditions.
