350 
ANNALS NEW YORK ACADEMY OF SCIENCES 
the drudgery of numerical calculations, but, in some cases, of devising 
methods. To aid matters, he founded a collection called The Astronomical 
Papers of the American Ephemeris to contain all the memoirs the carrying 
out the scheme should give occasion to. A large proportion of these memoirs 
is the work of Professor Newcomb. So numerous are they that we must be 
content with noticing only the more striking and important ones. 
The transits of Mercury from 1677 to 1881 were discussed, with the 
principal result of corroborating Leverrier’s assertion of 40" in the secular 
motion of the perijelion unaccounted for. 
In the years 1880-1882, Professor Newcomb made a determination of the 
velocity of light by the Foucault method. The construction of the instru¬ 
ment and the mode of handling it enabled a very large angle of deviation to 
be obtained; and thus an extraordinary degree of precision in the result 
was hoped for. Although this hope was not completely fulfilled, neverthe¬ 
less the concluded value is far in advance of all previous determinations. 
Shortly after, Professor Newcomb exhaustively treated the transits of 
Venus in 1761 and 1769 with the object of obtaining the constant of mutation 
from materia] afforded by observations with the transit circles of Greenwich 
and Washington. 
Professor Newcomb deemed that improvements could be made in the 
mode of deriving the periodic expressions needed in the subject of planetary 
perturbations. His method of treatment is elaborated in a memoir in the 
American Journal of Mathematics, Vol. Ill, and, at greater length, in a 
second memoir in the Astronomical Papers, Vol. Ill; and, finally, applica¬ 
tion is made to the four interior planets in a third memoir contained in the 
latter volume. For certain long-period inequalities in these planets it was 
found convenient to employ expressions involving time-arguments; this led 
to the composition of two memoirs in Vol. V, of the same collection. 
The secular variations of the elements of these planets are derived and 
the mass of Jupiter determined from observations of Polvrhymnia in the two 
following memoirs of the same volume. 
Professor Asaph Hall having found that there was a rather rapid retro¬ 
grade motion of the line of apsides of Hyperion, Professor Newcomb ex¬ 
plained this from the point of view of the variation of elements. By an 
inadvertency at the very end of his memoir he failed to obtain a correct 
value for the mass of Titan, the disturbing body. 
The completion of these preliminary investigations enabled Professor 
Newcomb to proceed at once to the composition of a memoir of the elements 
of the four inner planets and the fundamental constants of astronomy, which 
appeared as a supplement to the American Ephemeris for 1897. This 
memoir contains the data on which are founded the tables of these planets, 
