Good Measure

A falling apple was all Sir Isaac Newton needed to ascertain the law of gravity. Most scientific facts, however, do not drop out of the sky but have to be teased from nature and measured with precision instruments. In the 19th century a full "cabinet of physics? became a scientific—and pedagogical-necessity. 'Any physical principle could be demonstrated at a moments notice," says David Pantalony, visiting curator of some 4,000 scientific instruments used in Dartmouth classes during the course of more than two centuries. "Our collection shows what the daily practice of science actually looked like," he says. Emeritus physics professor Allen King added slide rules, lasers and other 20th-century tools "no one else thought of keeping," says Pantalony. The collection, housed in Wilder Hall, includes the instruments pictured here: a) octant circa 1790, used in navigation; b) 1870s-era. "electrical egg" discharge tube for demonstrating the flow of electricity; c)'1871 polarimeter for showing the wave properties of light; d) "Fox dip circle," circa 1848, for measuring the angle of the earths magnetic field; e) 1853 achromatic prism for optical demonstrations; f) binocular petrographic microscope, circa 1880, for geological research; and g) 1870 mirror galvanometer for measuring electric current. Dartmouth will showcase the collection of apparatus when it hosts an international conference on university science collections next year.