COMMUNICATIONS
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signal is flashed from the Observatory's signal mast and various signals are provided for time marking seismograms and other purposes.
The Observatory operates six seismometers, three of which are on loan from the Lamont Geological Observatory. A weekly report giving arrival times of significant earthquake waves is air mailed to the United States Coast and Geodetic Survey, and detailed analyses are made later and are published and sent to other scientific institutions. The results are included in the two inter- national bulletins, the International Seismological Summary and the bulletin of the International Union of Geology and Geophysics. The Observatory also participates in the Pacific Tidal Warning Service by sending telegrams to Honolulu Magnetic Observatory whenever intense earthquakes are recorded in Hong Kong. Normally one or two slight earthquake shocks are felt locally each year, and on 4th March this year many residents experienced shocks from an earthquake whose epicentre was about 80 miles north-north-east of the Colony.
Other Activities. Astronomical tables for use in the Colony are issued 'each year in the form of a booklet.
Details of research undertaken at the Observatory are given in Chapter 18.
THE YEAR'S WEATHER
The weather during 1961 was warmer and sunnier than usual. Although the rainfall during the first half of the year was less than two-thirds of the average amount, downpours associated with tropical storms in July and September compensated for this early deficiency, so that the total rainfall for the year was close to the normal value.
Gales due to tropical storms are unusual in Hong Kong before the end of June. Nevertheless, for the second consecutive year the Colony was harassed by an early typhoon. On 19th May 1961, typhoon 'Alice' became the first May storm to cause general gales over the Colony. Fortunately the winds were neither as persistent nor as strong as in typhoon 'Mary' of 9th June 1960. Four people lost their lives and twenty people were injured during the passage of 'Alice' but damage to crops, property and the fishing fleet was not great. Wind speeds during the major post-war storms and the