F 14-
capacity, constructed by Mr. Jeffries, were brought into use in connection with the Wireless Receiving Apparatus.
IX.—MISCELLANEOUS.
Earthquakes.—During the year 1918 several earthquake shocks were felt in Hongkong, the most severe occurring on February 13 as follows:——
A series of shocks commenced at 14h. 7m. on February 13, and continued at intervals until 16h. 50m. on the 14th. The first shock was the most severe and would be classed as No. 6 in the Rossi-Forel scale of 1 to 10 (Fairly strong shock, sleepers awakened; persons sufficiently startled to leave their houses, clocks stopped, oscillation of chandeliers). It commenced with a very feeble vibration at 14h. 7m. and increased until 14h. 9m. when the shaking of buildings was alarming. It died away at 14h. 12m. This was apparently the most severe earthquake ever felt in Hongkong.
At the Observatory, Kowloon, two clocks with seconds pendulums swinging in the meridian stopped; the Brock mean time clock at 14h. 9m. 9s., and the Dent Sidereal clock, at 14h. 9m. 38s. The Dent mean time clock whose pendulum swings in an E-W direction was not perceptibly affected. The barograph clock, which also swings in an E-W direction stopped at 14h. 10m.; the barograph trace was not perceptibly affected however. In the upstairs rooms several cracks appeared in the walls, glasses were overturned and the support of a cabinet shelf was shaken down. A seconds pendulum clock, swinging in an E-W direction was not stopped, but its rate, which had been practically zero for about 10 days, was affected to an extraordinary degree. By 17h. the clock had gained 2 minutes, and by 21h. it had gained 5 minutes. Its arc of vibration was reduced considerably. No explanation of these derangements was found.
One striking effect on the stopped clocks was the rapidity with which the pendulums came to rest. The bobs weigh about 15 pounds, and if allowed to swing freely will remain in motion for 2 hours or more; whereas they both came to rest a few minutes after the first vibrations were felt.
A small, short pendulum mantel clock at the Club House, Fanling, swinging in a N-S direction, stopped at 14h. 9m., while the seconds pendulum clock, which faces a little to the west of north was not perceptibly affected.
A seconds pendulum clock swinging in a NW-SE direction in Messrs. Falconer and Co.'s shop, Hongkong, stopped at 14h. 10m. but a similar clock, about 2 yards distant, swinging in a NE-SW direction was not perceptibly affected.
Of the two pendulum clocks used by the Telephone Company for driving their Standard Time Clocks, only one was stopped (14h. 9m.). They both face west. Several of the Asiatic Petroleum Company's pendulum clocks stopped, but none of those which were facing north.