History of the Discovery of the Planet Neptune. 197 
plored by geometers searching for the source of the disturbances 
of Uranus; and its discovery by Galle must be regarded as a 
happy accident. 
Some who are very zealous for the honor of astronomy, have 
been unwilling to admit that accident had any thing to do with 
the discovery of this planet. Such persons will probably admit 
that accident had some concern with the time when this problem 
began seriously to occupy the attention of astronomers. In the 
fore part of the year 1845, the true orbit and that of Le Verrier 
agreed in assigning to the planet eractly the same longitude ; 
but such a coincidence had not occurred for more than six hun- 
dred years before, and will not occur again in another six hun- 
dred years. If Le Verrier had obtained precisely the same ele- 
ments for the disturbing planet half a century earlier or later, and 
astronomers had searched for it, they would not have found it. 
‘The computed orbit would have served only to mislead—it would 
have diverted attention to the wrong part of the heavens,—for 
the planet would have been nearly thirty degrees distant from the 
assigned by the elements of Le Verrier. It was certainly a 
very singular, and a very “happy accident,” that an erroneous 
orbit which assigned to the planet its true direction in the - 
ens only once ina thousand years, should have been published to 
the world almost at the very instant of the coincidence. It is as 
if one should expect to find the place of Uranus by consulting 
the tables of Saturn. In the year 1852, Uranus may be found by 
king near the place assigned for Saturn in the Nautical Alma- 
nac, the two planets being then in conjunction ; but the like will 
not happen again for more than forty years. Would it not then 
be called an accident if the tables of Saturn should inform the 
observer exactly where to look for Uranus? 
To some it has appeared a matter of surprise, that the new 
planet was not sooner discovered. Le Verrier’s second memoir, 
which assigned the probable place of the disturbing body, was 
presented 
d to the Academy on the Ist of June; and his third me- 
