f light and darkness.

The one alteration will be in the notation of the hours, so as to
secure uniformity in every longitude. It is to be expected that this
change will at first create some bewilderment, and that it will be
somewhat difficult to be understood by the masses. The causes for such
a change to many will appear insufficient or fanciful. In a few years,
however, this feeling must pass away, and the advantages to be gained
will become so manifest that I do not doubt so desirable a reform will
eventually commend itself to general favor, and be adopted in all the
affairs of life.

Be that as it may, it seems to me highly important that a
comprehensive time system should be initiated to facilitate scientific
observations, and definitely to establish chronological dates; that it
should be designed for general use in connection with railways and
telegraphs, and for such other purposes for which it may be found
convenient.

The Cosmic day set forth in the recommendations would be the date for
the world recognizable by all nations. It would theoretically and
practically be the mean of all local days, and the common standard to
which all local reckoning would be referable.

With regard to the reckoning of longitude, I submit that longitude and
time are so intimately related that they may be expressed by a common
notation. Longitude is simply the angle formed by two planes passing
through the earth's axis, while time is the period occupied by the
earth in rotating through that angle. If we adopt the system of
measuring time by the revolution of the earth from a recognized zero,
one of these planes--that through the zero--may be considered fixed;
the other--that through the meridian of the place--being movable, the
longitudinal angle is variable. Obviously the variable angle ought to
be measured from the fixed plane as zero, and as the motion of the
earth by which the equivalent time of the angle is measured is
continuous, the longitude ought to be reckoned continuously in one
direction. The direction is determined by the notation of the hour
meridians, viz., from east to west.

If longitude be so reckoned and denoted by the terms used in the
notation of cosmic time, the time of day everywhere throughout the
globe would invariably denote the precise longitude of the place
directly under the mean sun. Conversely, at the epoch of mean solar
passage at any place, the longitude being known, cosmic time would be
one a