There ure several minerals, valuable in industry because of peculiar physical properties, the supply of which has been cut off by the war. Transparent fluorite, used in lenses, was formerly all obtained from Germany, but it is reported that deposits have now been found in Illinois of sufficient size and nuality to supply our needs. Calcite of Iceland-spar quality has, however, disappeared from the market. Can not some American mineralogist discover a workable deposit? Perhaps our readers can suggest other instances.