- F 17
Certain of the observations indicate that the correction is smaller at low than at high wet bulb temperatures, but this also requires further investigation.
It would appear that the first step towards the improvement of hygrometric methods is to derive corrections similar to the above for various types of screens, for use where aspirated thermometers are not available, and to construct new hygrometric tables based upon the best observations with rotating thermometers and some approved hygrometer. The question of units should also be considered.
Commencement of the Astronomical Day.-The following is my reply to a letter addressed to "The Observatory" by the Astronomer Royal and the Savilian Professor of Astronomy at Oxford, asking for expressions of opinion on the subject of a proposed alteration in the commencement of the Astronomical Day :-
Sir,
The Astronomer Royal,
Royal Observatory, England.
With reference to your letter of 1917, July 19, to the Editors of "The Observatory" on the subject of the commencement of the Astronomical Day, I should like to suggest that opportunity be taken of the proposed reform to adopt Universal Time; using the present 180th meridian as the new zero.
The meridian of Greenwich cuts the busiest trade route of the world twice; namely, in the English Channel and the Mediterranean Sea, and also cuts the Cape route, so would be an unsatisfactory zero from the sailor's point of view, whereas the present 180th meridian cuts but a few trade routes and is already used as the meridian at which the date is altered. Incidentally, the commencement of the day by the new Universal Time would correspond to the commencement of the present Astronomical Day.
There may be objections to the scheme, but I think they can hardly outweigh the advantages to be gained by abolishing Local Time, which was a necessity to the ancients but which appears to have no raison d'être in the 20th Century. The introduction of zone time was a half measure, pandering to the peculiar though apparently universal idea that the day's routine must be carried out at approximately the same clock time all over the world.
On the introduction of Universal Time each state, or even town, could arrange to regulate its routine by the most suitable hours of Absolute Time. As regards Daylight Saving, places in low latitudes would make the middle of the Working Day coincide with the meridian passage of the mean sun, and in high latitudes would alter office hours etc., according to season, in the same way as the present lighting up times are altered.
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