201. _Berlin Mean Time._--In the _Nautical Almanac_ the day is supposed
to commence at noon according to the custom of English astronomers.
Foreigners, however, ordinarily commence the astronomical day at
midnight, at least those of France, Germany, Italy, and Spain do. But
can you or any of your correspondents tell me whether it is from the
midnight succeeding, or the midnight preceding our noon of the same
number? For instance, taking the longitude of Berlin to be 0h 53m 35s .5
East, would the present moment, which is September 17, 3h 40m 30s
Greenwich mean time, if expressed in Berlin mean time, be September 17,
16h 34m 5s .5, or would it be September 16, 16h 34m 5s .5? (I have
reckoned to days by ordinals, as, 1st, 2nd, 3rd, &c., without a 0-day,
which, however, the foreigners generally use, employing a cardinal
number, the hours minutes, and seconds being considered as a fraction to
be added.) I ask this question because so many things now are announced
in Berlin mean time.