Earthquakes and Permanent Magnets

Abstract

IN a notice by Dr. A. B. Meyer in No. 116, vol. v. of NATURE, respecting earthquakes in the Island of Celebes, he states that the often-repeated story of the keepers of permanent magnets detaching themselves, and falling at the moment of an earthquake shock, was never verified in his experience. If I remember rightly, this peculiar action was first mentioned by a Frenchman living on the west coast of South America, and much doubted by many at the time. It is not likely that there is any difference between the effect of an American and an Asiatic earthquake on the magnet, if any such exists; but I must state, in corroboration of Dr. Meyer's note, that I have had a permanent magnet and keeper suspended in my study for many years, expressly for the purpose of testing this matter, and on no occasion of an earthquake has the keeper fallen from the magnet, not even in the terrific earthquake of 1863, which was so destructive to the city of Manila and the neighbouring provinces.