326 Davis’s Report on the Nautical Almanac. 
to say, the National Observatory took the lead, having oceasion to 
construct certain star-tables for the reduction of its own observa- 
tions. ‘I'he preparation of tables of reductions of the fixed stars 
to supply the place of the standard tables of Bessel, the date of 
which has expired, is in progress, and has received great facilities 
from the previous labors of the observatory. The new constants, 
above mentioned, will be introduced into the formula for the re- 
duction of the fixed stars. 
graphical execution are kept in view. A work comprising such 
a multiplicity of details may admit of many similar amendments. 
0 the above it should be added, that an entirely new reduc- 
tion has been made of the early Greenwich observations of Mars 
by Bradley, Bliss and Maskelyne, preparatory to a new theory 
and to new tables of this planet. This has conducted to a valu- 
able discovery in stellar astronomy noticed by Humboldt in the 
third volume of his Cosmos, and to the detection of some errors 
of former astronomers. 
A new method, with new tables, of clearing lunar distances 
will be given in the first number of the almanac, in which im- 
provements are presented leading to the correction of errors of 
ten, fifteen, or twenty minutes in the longitude, common to the 
methods at present in use; which errors may, in rare cases, 
amount to a whole degree. 
ere are two other signal advantages to be derived from the 
publication of the Nautical Almanac, the mention of which 
should not be omitted; they concern the navigator, surveyor, aS 
tronomer, and geographer. 
One of these is a more complete, full, and accurate table of 
latitudes and longitudes, particularly of American latitudes and 
longitudes, than is now anywhere to be found. ‘The multip 
leterminations of geographical positions form a part of the du- 
ties of the hydrographical office of the topographical bureau, a 
of the coast survey of the United States. They are publishe 
from time to time in the reports of these offices to Congress; an¢ 
there they remain for future reference, but necssarily combined 
with so much other matter that, even if they were always acces- 
sible, they would not be convenient for practical use. It b 
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