increased, since he almost exclusively observes according to
sidereal time, so that often a computation must be made in
order to ascertain whether the observations were made before
or after the midnight or moment of change of date. However,
this difficulty can be overcome by habit, and I believe that
scarcely any doubt will occur as soon as a uniformnity of
expression has established itself through the astronomical
world. As regards the ephemerides, we already employ, in
fact, the beginning of the date at midnight, since the
places of planets and comets, are generally computed for 12
o'clock midnight of Berlin or Greenwich or other places.
But these are points that have themselves long since been
discussed.

I scarcely need to say anything further. I would not
hesitate for a moment to give the preference to making the
change of date take place at midnight, according to civil
reckoning, in order to establish a uniformity with the
customs of civil life.

It, perhaps, may be important to remark that we could not
introduce this change immediately, since the ephemerides are
already computed and published for three or four years in
advance. It would, therefore, be well to fix the epoch of
change of normal dates to some distant time, such as 1890.

I remain, very respectfully yours,

W. VALENTINER.

I may also mention that the practice that prevails among astronomers
at the present time of reckoning the day from noon is by no means
without exceptions. There are very important astronomical tables which
reckon the day from midnight; for instance, in Delambre's Tables of
the Sun; in Burg's, Burckhardt's and Damoiseau's Tables of the Moon;
in Bouvard's Tables of Jupiter, Saturn, and Uranus, and in Damoiseau's
Tables of Jupiter's Satellites, mean midnight is employed as the epoch
of the tables. I may also mention that Laplace, in his Mecanique
Celeste, adopts the mean midnight of Paris as the origin from which
his day is reckoned. Hence there are great authorities, even among
astronomers, in favor of commencing the day at midnight.

General STRACHEY, Delegate of Great Britain. Sir, I observe that a
very eminent American authority is present in this room, I mean
Professor Hilgard. As he was invited to attend the meeting of this
Conference, I suggest that the views of the Conf