The Solomon Islands and Their Natives

by H. B. Guppy

Comparing the rainfall of the Solomon Islands with some results obtained in other parts of the Pacific, I would draw attention to the small rainfall of Port Moresby on the south-east coast of New Guinea, where 34·44 inches were registered at the Mission Station in 1875.[497] In Fiji the rainfall appears to vary between 60 and 250 inches per annum, according to the degree of elevation above the sea, and to the position of the station on the lee or weather sides of the islands, the greatest annual falls occurring in the interior of the large islands.[498] In Oahu, one of the Sandwich Islands, during 1873, the rainfall at the coast was 37·85 inches; whilst at a distance of 2³⁄₄ miles in the interior, it was 134·06 inches, the elevation being only 550 feet above the sea.[499]

[497] Stone’s “A Few Months in New Guinea,” p. 143.

[498] Rain-gaugers have been numerous in this colony, and their list would extend beyond the limits of a foot-note. (Vide Home’s “Year in Fiji,” &c., &c.)

[499] Mosely’s “Naturalist on the ‘Challenger,’” p. 497.

I will now make a few remarks on the barometric pressure, temperature, and other features of the meteorology of this group. They are based on the results of the observations made by Lieutenant Leeper on board the ship, and by Mr. F. Howard at Ugi. (Tables appended.)

As is usual in these regions of the Pacific, the fluctuation of the barometer, whether daily, yearly, or monthly, is very small. Thus, the range during the 22 months we passed in the group, was from 29·83 to 30·18 inches, or about a third of an inch; whilst the average monthly range was rather under a quarter of an inch, and the usual diurnal variation about ·04 of an inch.

Whilst endeavouring to compare the temperatures of the different seasons, I have mainly used the Ugi register, since it gives a continuous record for more than a year. At Ugi in 1883, the portion of the year from June to September inclusive was slightly the coolest, but the difference in the means was not 2°; and, in truth, taking all the thermometric observations into consideration, the seasons are scarcely distinguished by their temperatures. As Lieutenant Leeper[500] remarks in his report, the temperature varies but little all the year round, the monthly mean varying between 80° and 85°. The annual mean temperature may be placed at 82° to 83°, and the range from 75° to 95°. The daily variation is considerably affected by the exposed or protected position of any locality at the coast. Judging, however, from the data at my disposal, it is usually less than 10°, e.g., 79° at night, and 88° at mid-day.

[500] Vide Quart. Journ. Roy. Met. Soc. vol. XI., p. 309. The instruments used on board were previously verified at Kew. From want of leisure, Lieut. Leeper was unable to do much more than tabulate his observations. I have therefore extracted from them such general facts and inferences as they sustain.

From the hygrometrical observations, it may be inferred that the climate of these islands is generally very moist. The relative humidity, taking 100 as saturation, ranged at Ugi in 1883 from 54 to 100; but the monthly range was usually from 72 to 95, the mean for the year being 83.[501] This mean degree of relative humidity is much greater than that of Levuka in Fiji which would seem to average about 70;[502] but in truth there is little necessity for me to remark further on this well-known feature of the climate of these islands. Yet, I should add that this proportion of aqueous vapour would not necessarily be oppressive in a temperate latitude. In a tropical climate, however, any influence that retards the evaporation from the skin of the normally excessive perspiration, is a cause of personal discomfort, such as would not be experienced in a drier locality lying in the same latitude. The effects of this combination of heat and moisture are to be seen in the rankness of the vegetation, and in the rapid rusting of steel. Although the foregoing remarks may be taken as generally applicable to the group, it should be stated that on the lee side of a mountainous island, such as the western end of Guadalcanar, there is a comparatively dry atmosphere, and the difference is also shown in the character of the vegetation.