Description of "an instrument cheifely to demonstrate thatt one man going E:ward till hee com round aboute the world shall loose a whole day and a nightt of 24 houres, and contrarywise another thatt traveils W:ward shall gett as much to a third man thatt keepes one station, soe that when they come together they shall have 3 severall daies all uppon one day, to be experimented best under the Eaquinoctial", Date not recorded at time of cataloguing