The Earthquakes in Greece

THE severe earthquake felt in Greece on April 27 at 9.20 p.m. was observed in Birmingham by the aid of a delicate bifilar pendulum, with which observations are now being made on behalf of the Earth Tremor Committee of the British Association. This instrument, designed by Mr. Horace Darwin, and made by the Cambridge Scientific Instrument Company, is described in the Report of the Committee presented at the Nottingham meeting last year.1 I may merely mention here that a tilt of the ground in an east-west direction is magnified about 3000 times by the rotation of a mirror about a vertical axis; and that the image of a fine wire in front of a movable gas-jet, after reflection by the mirror, is observed in a fixed telescope in the passage outside the cellar in which the pendulum is erected.