Longitude at Sea for the perfecting the Art of Navigation."

About the middle of the last century the lunar tables were so far
improved that Dr. Maskelyne considered them available for
attaining this long-wished-for object. The method which I think
was then, for the first time, proposed was the now familiar one of
lunar distances. Several trials of the method were made by
accomplished gentlemen who considered that nothing was wanting to
make it practical at sea but a Nautical Ephemeris. The tables of
the moon, necessary for the purpose, were prepared by Tobias
Mayer, of Gottingen, and the regular annual issue of the work was
commenced in 1766, as already stated. Of the reward which had been
offered, three thousand pounds were paid to the widow of Mayer,
and three thousand pounds to the celebrated mathematician Euler
for having invented the methods used by Mayer in the construction
of his tables. The issue of the Nautical Ephemeris was intrusted
to Dr. Maskelyne. Like other publications of this sort this
ephemeris has gradually increased in volume. During the first
sixty or seventy years the data were extremely meagre, including
only such as were considered necessary for the determination of
positions.

In 1830 the subject of improving the Nautical Almanac was referred
by the Lord Commissioners of the Admiralty to a committee of the
Astronomical Society of London. A subcommittee, including eleven
of the most distinguished astronomers and one scientific
navigator, made an, exhaustive report, recommending a radical
rearrangement and improvement of the work. The recommendations of
this committee were first carried into effect in the Nautical
Almanac for the year 1834. The arrangement of the Navigator's