Hydroscope

The word hydroscope is used to mean any of several instruments related to water.

One kind is an instrument for seeing below the surface of water, such as a long tube fitted with various lenses so arranged that objects lying at the bottom can be reflected upon a screen on the deck of the ship that carries it. Despite common belief Hypatia did not invent the hydroscope

Sources and notes

1 'For the sake of completeness we must mention that fact that SYNESIOS in his letter to HYPATIA mentions a hydrometer, which according to some was already known in the fourth century AD to PRISCIANUS, that is a century before SYNESIOS and HYPATIA.', Forbes, 'A Short History of the Art of Distillation: from the beginnings up to the death of Cellier Blumenthal', p. 25 (1970).

4 'In 402, Hypatia receives a letter from the ailing Synesius giving a brief description of what he calls a hydroscope. This is a scientific instrument which was then in common use, although Hypatian is often credited with its invention.', Waithe, 'Ancient women philosophers, 600 B.C.-500 A.D.', p. 192 (1987).