THE MOON'S PHASES, &C.

The times of New Moon, First Quarter, Full Moon, and last Quarter, are given in the Calendar to the nearest local civil day. Thus if New Moon occur on any day between midnight and 5 hr. 7 min. a.m. Greenwich time, the New Moon is referred to the previous day in the above Calendar.

EQUATION OF TIME.

The equation of time is a correction which must be applied to apparent time or time obtained from observation of the Sun, in order to obtain mean time, or the time shown by a properly regulated clock.

The last column in each month of the Calendar above gives this correction for every day in the year. Care must be taken to add or to subtract the correction according to the precepts.

For instance on Jan. 4th we must add 5 min. to the time shown by a good Sundial in order to obtain the clock time; but on Oct. 4th we must subtract 11 min. and so on.

SUNRISE AND SUNSET.

The mean times of sunrise and sunset for every day in the year, given in the Calendar above, have been computed for the latitude of Kingston and include the effect of refraction.

TIDES ON THE COASTS OF JAMAICA.

As the rise and fall of the Tides round Jamaica do not exceed 10 or 11 inches, we clearly do not require the times of High and Low water for nautical purposes, and an extension of the Calendar in the Handbook so as to include the daily tides throughout the year, would prove to be labour lost.

But sometimes we want to know, however roughly, whether it is High or Low water; for instance the sea often rises or falls so much above or below its usual level as to attract the general attention of those who live near the shore, and then the question of tide arises; for if the unusual rise or fall be at times of Low or High water, of course the disturbance noted is all the greater.

Such disturbances are produced by strong prevailing winds at a distance, by hurricanes, and by earthquakes.

But putting these exceptional circumstances aside, the tide has a curious effect upon the daily weather which may be thus briefly expressed :-a rising tide increases the local action of the weather. And this effect, though confined to the coasts, has been found to exist all over the world.

Hence the following approximate and general table has been drawn up for Jamaica; it is based upon an Establishment of 11 hrs. O min. at Port Royal given by Captain Green, U.S.N. (Navigation of the Caribbean Sea and Gulf of Mexico, vol. I, p. 244); and the day of New or Full Moon from which the following days are to be reckoned should be expressed in civil local time, as given in the Calendar above.

In each semi-lunation there is always one day on which there is but one tide. It will be noticed that for Jamaica this day occurs two days after New or Full Moon. The table is probably quite correct for the first five or six days and for the last two days; but for the remaining days "the age of the tide" may cause an error not exceeding 15 min.

ECLIPSES, 1893.

I. A total Eclipse of the Sun, April 16, invisible in Jamaica.

II. An annular Eclipse of the Sun, October 9, visible in Jamaica as a partial Eclipse. The following times of contact and of greatest Eclipse have been computed for Kingston:

First contact
Greatest Eclipse

Last contact

hr. min.

3 43 p.m., Kingston Mean time.

4 32

5 21 66

66

The first contact will occur at a point a little to the left of the lowest point of the Sun's limb. The last contact will occur near the extreme left of the Sun's limb. At the time of greatest Eclipse the dark disc of the Moon will have advanced on the disc of the Sun somewhat less than one-fourth of the diameter of the Sun. The Sun will set at 5 hr. 41 min pm.

LATITUDE AND LONGITUDE OF KINGSTON.

DURING the years 1875 and 1876 the latitude and longitude of Kingston were determined by Captain F. M. Green, U.S.N., with great accuracy.

The station at Kingston was 12 feet west of the centre of the pedestal on which the statue of Lord Rodney was mounted, at the lower end of King Street, near the marketplace, and overlooking the harbour.

The latitude of this station was obtained from 43 observations of pairs of stars, by means of an instrument suited for the purpose. It was a combination of a transitinstrument and a zenith-sector. The latitude thus found was 17° 57' 41.0 N.

The longitude of this station was determined by telegraphic signals between Greenwich and Washington, Washington and Key West, and so on to Havana, Santiago de Cuba and Kingston; the three latter sections forming part of the work conducted by Captain Green. The longitude thus found was 5hr. 7m. 10.65 sec. west of Greenwich, or in arc 76° 47'39.8 W.; that is to say, when it is mean noon at Kingston it is 5hr. 7m. 10.65 sec. p.m. at Greenwich.

LATITUDE AND LONGITUDE OF THE KEMPSHOT OBSERVATORY

(NEAR MONTEGO BAY).

THE transit-instrument is adapted for the approximate determination of zenithdistances, and by means of 50 observations of the stars during the years 1875, 1876 and 1877; the latitude of the pedestal of the transit-instrument was found to be 18° 24/50/8 N.

By means of telegraphic signals the longitude of the Observatory was accurately determined in 1882. On the night of the 28th Nov. 225 signals were exchanged between Kingston and Montego Bay, which placed the Observatory 4 m. 18.865 sec. west of Lord Rodney's statue; on the following night 116 signals were exchanged, which placed the Observatory 4 m. 18.875 sec. west of the statue: and by adopting 4 m. 18.87 sec. as the true difference of longitude, it follows that the transit-instrument of the Kempshot Observatory is 5 hrs. 11 min. 29.52 sec. west of Greenwich, or in arc 77° 52′ 22.8.

The top of the pedestal of the transit-instrument is 1773 feet above the mean sea-level.