hitherto employed is such that I can only state what has been done
by mentioning each planet in detail.

For Mercury, new tables were constructed by Professor Winlock,
from formulae published by Le Verrier in 1846. These tables have,
however, been deviating from the true motion of the planet, owing
to the motion of the perihelion of Mercury, subsequently
discovered by Le Verrier himself. They are now much less accurate
than the newer tables published by Le Verrier ten years later.

Of Venus new tables were constructed by Mr. Hill in 1872. They are
more accurate than any others, being founded on later data than
those of Le Verrier, and are therefore satisfactory so far as
accuracy of prediction is concerned.

The place of Mars, Jupiter, and Saturn are still computed from the
old tables, with certain necessary corrections to make them better
represent observations.

The places of Uranus and Neptune are derived from new tables which
will probably be sufficiently accurate for some time to come.

For the moon, Pierce's tables have been employed up to the year
1882 inclusive. Commencing with the ephemeris for the year 1883,
Hansen's tables are introduced with corrections to the mean
longitude founded on two centuries of observation.

With so great a lack of uniformity, and in the absence of any
existing tables which have any other element of unity than that of
being the work of the same authors, it is extremely desirable that