140 
UPDEGRAFF. 
foremost astronomer of the 19th century. In the most pro- 
gressive age in the history of the world, he occupies a place 
corresponding to that of the greatest astronomers from 
Hipparchus to Gauss, and appreciation of his work will in- 
crease with the passage of time. His constructive genius 
siezed upon every instrumentality for accomplishing results. 
That our country should produce such a man so early in its 
history is just cause for national self congratulation, and 
none the less that this distinction is justly appreciated and 
freely accorded us by the world. 
A word should be said about Professor Newcomb’s work on 
the motion of the moon, which he began when a young man, 
and continued at intervals throughout his whole life. It is 
well known that the lunar theory is the most difficult subject 
in the whole range of celestial mechanics. Professor New- 
comb’s work in this direction was largely of an empirical 
character. In 1861 he published a paper on the differences 
between the observed and predicted places of the moon, and 
early in the seventies he visited Europe for the purpose of 
securing and making use of old observations of occupations 
of stars for the purpose of extending backward our knowledge 
of the moon’s motion. As a result of this work, Professor 
Newcomb was able to obtain corrections to the moon’s longi- 
tude which have been used for many vears to increase the 
accuracy of the predicted places. Though further research 
was necessary, pressure of other work made it impossible for 
this task to be completed in the Nautical Almanac Office 
prior to Professor Newcomb’s retirement for age in 1897. 
Several years later he was able to take it up again under the 
auspices of the Carnegie Institution, and about a year ago 
arrangements were made to have the work finished in coopera- 
tion with the Nautical Almanac Office, and for printing the 
results as one of the Astronomical Papers of the American 
Ephemeris. , . * 
This work was nearly completed when, last May, Professor 
Newcomb learned that he had only a few weeks to live. Then 
in his enfeebled condition, and when suffering great pain, he 
applied himself to the task of directing the finishing touches; 
