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 occurs 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 hr. 0 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, 1895.

I. A total Eclipse of the Moon, March 10th, visible in Jamaica.

Kingston mean time.

II. A partial Eclipse of the Sun, March 25th, invisible in Jamaica.
III. A partial Eclipse of the Sun, August 20th, invisible in Jamaica.
IV. A total Eclipse of the Moon, September 3rd, visible in Jamaica.

V. A partial Eclipse of the Sun, September 18th, invisible in Jamaica.

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 market-place, 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."8W.; 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,

METEOROLOGY.

Totals

...

The table above contains the results of the observations made at Kingston, Jamaica, between June, 1880, and May, 1890, inclusive. Between June, 1880, and December, 1886, the readings were taken at intervals of eight hours, namely, at 7 a.m., 3 p.m., and 11 p.m., local mean time; the daily means of pressure, temperature, dewpoint, humidity, &c., were assumed to be the means of the three eight-hourly readings, but since January, 1887, the readings have been taken at 7 a.m. and 3 p.m. only; and the daily means were deduced by applying to the 7 a.m. and 3 p.m. readings their proper reductions; and from the daily means the monthly means given in the table have finally been deduced.

The readings were taken with great care and regularity, and they were all corrected for instrumental errors.*

In the second column the Barometric Pressure is of course referred to the sealevel.

In the seventh column the wind is stated to be S.E., and this is in consequence of the regularity of the daily sea-breeze, which is almost invariably S.E. at Kingston. In the eighth column the Dew point has been found from the Dry and Wet-bulb thermometers by means of Glaisher's factors; of course Wet-bulb and Tension-ofVapour columns could have been added, but it seemed useless to fill up the table with columns easily deducible the one from the other.

In the tenth column the amount of cloud is given as a percentage of the whole sky. In the eleventh and twelfth columns are given for the period in question the average monthly Rainfall at the Public Works Office, Kingston, and for the whole Island, the latter being deduced from about 150 stations.

The remaining columns give for each month the average number of deaths in Kingston from a few groups of diseases, and the average totals; they have been taken from the returns published monthly by Mr. S. P. Smeeton, the Registrar-General. The following are some of the relations existing among the different columns.

(i.) PRESSURE and Rainfall.

If the Barometric Pressure be compared, -not with the Kingston Rainfall on account of its highly local character, but with the general Island Rainfall it will be seen that a certain relation exists :

Rainfall 50 (30.100-pressure) or in words, if the pressure during any month be subtracted from 30.100, and if the difference be multiplied by 50, the product will not be far from the Rainfall in inches.

This remarkable relation requires much further consideration, for which we have at present neither space nor time.

(ii.) TEMPERATURES,

The mean temperature does not greatly differ from half the sum of the maximum and minimum temperatures. In order to make the agreement closer we must take into account the Range, or difference between the maximum and minimum, the humidity, and the amount of cloud which covers the sky.

The maxima and minima given in the table were deduced from daily readings, and their differences give the daily range; but by picking out of the original record or register the highest and lowest temperatures for each month we get the absolute max. aud min. To prevent confusions the absolute max. and min. were not inserted in the table; their averages are, however, 4° above and below the max. and min. deduced from daily readings.

Again since June, 1880, the highest temperature was 96.7° recorded on the 20th August, 1891, and the lowest temperature was 56.7° recorded on the 4th December, 1887.

And lastly the Mean Daily Temperature is here given for each complete year :

The Thermometers were exposed in the Stevenson screens over a grass lawn four or five feet above the ground.

(iii.) VAPOUR..

The humidity of the air is the ratio of the amount of vapour present to the amount necessary for saturation,-saturation being taken at 100; so that humidity indirectly measures the drying power of the air.*

By comparing the Dew-point with the Minimum Temperature we see that there is an almost constant difference of about half a degree. The nights in Kingston therefore cool down until the temperature of the air four or five feet above the ground is a little above the Dew-point; but on the ground the temperature is below the Dew point, dew is precipitated, latent heat given out, and the further fall of temperature arrested.

We must now consider the connection between these Meteorological results and. the number of deaths in Kingston.

(iv.) INFANTILE DISEASES.

Under this heading is given the number of deaths in Kingston each month of the year from infantile diseases not otherwise specified in the books of the Registrar General.

By comparing the numbers in this column with the total monthly numbers in the last column, it will be seen that the former are fairly proportioned to the latter, although, indeed, their variation from their mean or average is larger.

Consequently whatever cause systematically affects the total monthly numbers, the same cause affects young children rather than adults.

(v.) TOTAL MONTHLY NUMBERS.

The total number of deaths vary on the average with considerable regularity from month to month; the maximum, 139. occurs in March; the minimum, 79, occurs in September.

This variation is intimately connected with the temperature; and remembering that there must always be a considerable interval of time between such a cause and such an effect, it appears that the maximum occurs after the lower temperatures and that the minimum occurs after the higher temperatures; or in other words, the death-rate greatly increases after our cool season and greatly diminishes after our

warm season.

(vi.) FEVER.

There are but few deaths from this cause, and they are distributed throughout the year with considerable uniformity. One maximum occurs in July after the May rains, and another occurs in November, December and January after the October rains. These maxima are due to inalaria set free by the drying-up of the ground after heavy rains.

In many countries in the tropical parts of the earth it is dangerous to disturb the soil,-as for instance in the Gold Coast Colony in Africa, because the soil teams with malaria; and so it must have been in the earlier days of Jamaica when the land was first cleared of forests and when the soil was first turned up for the cultivation of the sugar-cane: but now we, for the most part, only feel the effects of water returning upwards from considerable depths below the surface of the ground; for with the water ascend those specific disease-germs which produce malarial fever when they can secure a footing in the blood and develop specific organism.

"The germs of these organisms float about in the air from place to place and gain positions enabling them to enter the blood of some animal organism, say man, where they can grow and flourish, provided they are able to successfully encounter their mortal foes, the white corpuscles of the blood. If these white corpuscles are strong and vigorous, they will overpower the foreign growth and kill it. If on the other hand they are weak and feeble, and the germs very numerous, the foreign growth may get a secure footing and spread luxuriantly changing the character of the fluids of the body, coagulating, it may be, the albumen, and otherwise setting up the unnatural display of functions which we call disease."t

*If the drying power of the air were measured from 0 to 100, Humidity plus drying power, would always be 100% † Nature, Vol. 31, p. 267,