A Magnetic Detecter

A clever eontrivance has been invented for thfr detection of sm;ül pieces of magnetizable metal, sncü as needles, tacks, steel and iron chips, etc., thatmay have eBtered the human bqdy nnawares and bidden theinselves in ,the skin or deeper tissues. The instrument was devised by Dr. J. B. Williams and consists essentialiy oí a partially astatic coinbination ot small magnetic needles suspended with.in a glass ttibe, the tube being covered with tinfoil to minimize electric action, except for a small space through which the needie can be observed. It 13 claimed that the instrument is snfficiently delicate to detect the presence of one-eighth of an inch of steel or iron wire at a distance of six inches f rom itself. -