question,
therefore, which we have now to decide is, when shall this day of the
initial meridian be considered to commence? And the proper answer to
be given to this question does not appear to me in any degree
doubtful.

In modern times it is the universal practice to reckon dates by _days_
and not by _nights_. The word "day" is used in two different
significations, being sometimes applied to the period of daylight and
sometimes to the period of 24 hours, including both day and night; but
in whichever of these senses the word _day_ is employed, the term
mid-day has one and the same signification, viz., the instant of noon
or of the sun's passage over the meridian. In the present case, where
we are concerned with mean time, mid-day means the instant of mean
noon, or of the passage of the mean sun over the meridian.

Accordingly, the civil day, by which all the ordinary affairs of life
are regulated, begins and ends at midnight, and has its middle or
mid-day at noon.

It appears, then, most natural that the universal day should follow
this example, and should begin and end at the instant of mean midnight
on the initial meridian, and should have its middle at the instant of
mean noon on the same meridian.

I fail, therefore, to see the force of the reasons which induced the
Conference at Rome to recommend that the universal day should commence
at _noon_ on the initial meridian.

The only ground for making this recommendation is that astronomers,
instead of adopting the use of the civil day, like the rest of the
world, are accustomed to employ a so-called astronomical day, which
begins at noon. The advantage thus gained is that they avoid the
necessity of changing the date in the course of the night, which is
the time of their greatest activity; but this advantage is surely very
small when compared with the inconvenience of having two conflicting
methods of reckoning dates, and of being obliged to specify, in giving
any date, which mode of reckoning is adopted. If this diversity is to
disappear, it is plain that it is the astronomers who will have to
yield. They are few in number compared with the rest of the world.
They are intelligent, and could make the required change without any
difficulty, and with very slight or no inconvenience.

The requisite changes in the astronomical and nautical ephemerides
would be easily made. As these ephemerides are published several years
in advance, there would be plenty of time