NOVEMBER 12, 1897. ] 
In 1849 the American Nautical Almanac 
office was established by a Congressional 
appropriation. The title of this publication 
is somewhat misleading in suggesting a 
simple enlargement of the family almanac 
which the sailor is to hang up in his cabin 
for daily use. The fact is that what started 
more than a century ago as a nautical al- 
manac has since grown into an _ astro- 
nomical ephemeris for the publication of 
everything pertaining to times, seasons, 
eclipses and the motions of the heavenly 
bodies. It is the.work in which astro- 
nomical observations made in all the great 
observatories of the world are ultimately 
utilized for scientific and public purposes. 
Each of the leading nations of western 
Europe issues such a publication. When 
the preparation and publication of the 
American Ephemeris was decided upon the 
office was first established in Cambridge, 
the seat of Harvard University, because 
there could most readily be secured the tech- 
nical knowledge of mathematics and theo- 
retical astronomy necessary for the work. 
A field of activity was thus opened, of 
which a number of able young men who 
have since earned distinction in various 
walks of life availed themselves. The head 
of the office, Commander Davis, adopted a 
policy well fitted to promote their develop- 
ment. He translated the classic work of 
Gauss, Theovia Motus Corporum Cclestiwm, 
and made the office a sort of informal 
school, not, indeed, of the modern type, but 
rather more like the classic grove of Hellas, 
where philosophers conducted their discus- 
sions and profited by mutual attrition. 
When, aftera few years of experience, meth- 
ods were well established and a routine 
adopted, the office was removed to Wash- 
ington, where it has since remained. The 
work of preparing the ephemeris has, with 
experience, been reduced to a matter of 
routine which may be continued indefi- 
nitely with occasional changes in methods 
SCIENCE. 
717 
and data and improvements to meet the 
increasing wants of investigators. 
The mere preparation of the ephemeris 
includes but a small part of the work of 
mathematical calculation and investigation 
required in astronomy. One of the great 
wants of the science to-day is the re-reduc- 
tion of the observations made during the 
first half of the present century, and even 
during the last half of the preceding one. 
The labor which could profitably be de- 
voted to this work would be more than 
that required in any one astronomical ob- 
servatory. Itis unfortunate for this work 
that a great building is not required for its 
prosecution, because its needfulness is thus 
very generally overlooked by that portion 
of the public interested in the progress of 
science. An- organization especially de- 
voted to it is one of the scientific needs of 
our time. 
In such an epoch-making age as the pres- 
ent it is dangerous to cite any one step as 
making a new epoch. Yet it may be that 
when the historian of the future reviews the 
science of our day he will find the most re- 
markable feature of the astronomy of the 
last twenty years of our century to be the 
discovery that this steadfast earth of which 
the poets have told us is not after all quite 
steadfast ; that the north and south poles 
move about a very little, describing curves 
so complicated that they have not yet been 
fully marked out. The periodic variations 
of latitude thus brought about were first 
suspected about 1880, and announced with 
some modest assurance by Kistner, of Ber- 
lin, a few years later. The progress of as- 
tronomical opinion from incredulity to con- 
fidence, was extremely slow until, about 
1890, Chandler, of the United States, by an 
exhaustive discussion of innumerable re- 
sults of observations, showed that the lati- 
tude of every point on the earth was sub- 
ject to a double oscillation, one having the 
period of a year, the other of 427 days 
