Dip Circle, Number 226

Written for Brought to Light by: Robert Bartnik. Research Group: Robert Bartnik, Phoebe Ross, Daniel Sivan.

Dip circle 226 in wooden box with two pairs of dip needles and two bar magnets. Believed to have come from the former Adelaide Observatory. Maker: Cambridge Scientific Instrument Co. Ltd, England.

This dip circle, also known as a dip needle, was likely bought for the University of Adelaide by Nobel Prize winning scientist William Henry Bragg. It was manufactured by the Cambridge Scientific Instrument Company under the leadership of Charles Darwin's son, Horace Darwin. Dip circles like these were unique precision instruments used to study magnetism. Specifically, they measured the 'dip' angle between the horizon and the Earth's magnetic field. An earlier version of this dip circle was used by British explorer James Clark Ross, famous for locating the North Magnetic Pole in 1831.

Various types of dip circles have been developed and used since the 16th century however the University of Adelaide's Historical Collections Scientific Apparatus Catalogue from 1986 dates this item as being manufactured between 1900-1919. This coincides with the end of the first World War, which saw an era of technological advancements which resulted in the Dip Circle becoming obsolete.

Metal.