Page:A Voyage of Discovery and Research in the Southern and Antarctic Regions Vol 2.djvu/99

] occur at 9 and 10  when it is greatest, and 4  and 3  when it is least; and the difference amounts to .041 inch.

The mean temperature of the surface of the sea is 56º.

In like manner for the next month, the mean temperature of the air derived from the second table, which comprises an abstract of all the observations made between the 18th September and 18th October, an interval of thirty-one days, and correspond to the 3rd October, is 57º.9,—an increase of four degrees in the mean temperature of the month as the season advances, whilst that of England increases about six degrees. The range of temperature at New Zealand is from 73º to 39º; in England, in April, it is 74º to 29º.

The mean temperature of the dew point is 53º, making the amount of dryness 4º.9; the degree of moisture has consequently varied very little, being .847, the elasticity of vapour, .444, the quantity of rain, 4.1 inches. The greatest fall of rain during the period occurred between 5 and midnight of the 17th of October, amounting to 2.84 inches, the barometer being rather below its mean height for the season, and the wind strong from the northward.

The mean height of the barometer is 30.118, and its range .738 inch. The greatest pressure occurs at 9 and 10, and the least pressure at 4  and 4 : the difference amounts to .044 inch.