In 1593, Galileo Galilei took time off from astronomy and promulgating heresy to invent a thermoscope for measuring heat. In 1833, Carl Friedrich Gauss invented a device to measure the strength of a magnetic field, and in 1908 Hans Geiger made a detector for ionising radiation. At this very moment astronomers are detecting planets around distant stars by measuring how much their orbits wibble, and the clever people at CERN are smashing particles together in the hope that Doctor Who will turn up and tell them to stop.
