H.—34,

APIA OBSERVATORY, SAMOA. Acting-Director : H. B. Sapsford. The usual programme of work in geophysical subjects was continued during the year 1938-39 at the Apia Observatory. The principal subjects of study were terrestrial magnetism, seismology, meteorology and atmospheric electricity. Terrestrial Magnetism. Absolute observations of horizontal intensity, declination, and the angle of dip were made, using magnetometer No. 9 C.I.W. (on loan through the courtesy of the Carnegie Institution of Washington) and the Schulze earth inductor No. 2. The variations in horizontal intensity, declination, and "vertical intensity were recorded continuously by photographic registration. The instruments used in this connection were Eschenhagen variometers for declination and horizontal intensity and a Godhavn balance for vertical intensity. Seismology. The Wiechert horizontal seismograph (mass 1,000 kilograms) and the Wiechert vertical seismograph (mass 80 kilograms) gave satisfactory service during the year. Nearly all the major earthquakes which were reported from other stations were recorded at Apia. In particular, good traces were obtained of the shock near Alaska (10th November, 1938) and of those in Chile (25th January, 1939) and the Solomon Islands (30th January, 1939). The instruments are not designed to record strong local shocks, and when these occur the pens are usually thrown off. A local shock-recorder would be very useful for the study of near earthquakes in this region. Meteorology. Surface observations of the meteorological elements were made three times a day, and frequent measurements of the upper winds were taken by means of pilot balloons. Regular daily pilot balloon ascents were commenced in July, 1938. Two synoptic charts of the weather in the South West Pacific Region were plotted every day, and collective broadcasts of weather reports were issued. During the hurricane season local reports were posted in Apia, and the Observatory frequently supplied forecasts and information, at all hours of the day and night, to various people. Several of the resolutions whuch were passed at the Meteorological Conference in Wellington in 1937 have been put into effect.

Meteorological Summary, Apia, 1938.

123

Month. Pressure. Temperature. Rainfall. Sunshine. Wind. {V ct.IIl.J In. °P. In. Per Cent. Hours. Miles per Hour January .. I 29-737 80-2 20-64 79 210-7 5-7 February .. 29-760 79-3 13-35 80 142-0 5-3 March .. .. 29-815 79-2 10-80 76 185-9 6-0 April .. .. 29-819 79-1 6-57 80 202-5* 4-1 May .. .. 29-836 78-5 8-79 79 210-5 6-4 June .. .. 29-872 79-0 3-73 79 236-3 7-0 July .. .. 29-890 79-8 5-86 76 290-8 9-7 August.. .. 29-891 78-7 5-26 79 254-7 9-8 September .. 29-896 79-0 2-13 72 297-6 8-3 October .. 29-899 79-0 8-04 73 288-8 6-4 November .. 29-765 77-9 33-35 84 99-4 5-9 December .. 29-791 79-6 20-94 80 237-5 7-9 Total .. .. .. 136-46 .. 2,656-7 Mean .. 29-831 79-1 .. 78 .. 6-9 * One day missing.