256 NATIONAL ACADEMY OF SCIENCES 
COMMITTEE ON THE TRANSIT OF VENUS. 1871 anv 1881 
Two transits of Venus across the sun’s disc have occurred 
since the foundation of the Academy fifty years ago. ‘These 
took place in 1874 and in 1882. No more will occur until the 
year 2002. As early as 1870, or even before that date, plans 
began to be formulated for observing these rare celestial phe- 
nomena. At the session of the Academy held in Washington 
in April, 1870, Simon Newcomb read a paper, “ On the coming 
transits of Venus and the mode of observing them,” in which he 
said: 
“ce 
.... Although the next transit does not occur for four years, the pre- 
liminary arrangements for its observation are already being made by the govern- 
ments and scientific organizations of Europe. It is not likely that our govern- 
ment will be backward in furnishing the means to enable its astronomers to take 
part in this work. The principal dangers are, I apprehend, those of setting out 
with insufficient preparation, with unmatured plans of observation, and without a 
good system of codperation among the several parties. For this reason I beg leave 
to call the attention of the Academy to a discussion of the measures by which we 
may hope for an accurate result.” 
After explaining the methods which it was necessary to 
employ, he remarked: 
ace 
. . . . | have endeavored to show that no valuable result is to be expected 
from hastily-organized and hurriedly-equipped expeditions; that every step in 
planning the observations requires careful consideration, and that in all the pre- 
paratory arrangements we should make haste very slowly. I make this presenta- 
tion with the hope that the Academy will take such action on the matter as may 
seem proper and desirable.” 7° 
At the same session a committee was appointed by the Presi- 
dent of the Academy to secure the successful observation of the 
transit. It consisted of Benjamin Peirce, Superintendent of the 
Coast Survey, Rear-Admiral Charles H. Davis, at that time in 
charge of the Naval Station at Norfolk, and Commodore B. F. 
Sands, Superintendent of the Naval Observatory. 
In his report for the year 1870, the Secretary of the Navy, 
George M. Robeson, remarked: 
Amer. Journ, Sci., ser. 2, vol. 50, 1870, pp. 74-83. On the mode of observing the coming 
Transits of Venus. By Simon Newcomb. Read before the National Academy of Sciences, 
April 13, 1870. 
