hydroscope การใช้

• A hydroscope is an optical device used for making observations deep under water.
• Hypatia is given credit for inventing the hydrometer ( or hydroscope ) sometime in the late 4th century or early 5th century.
• Despite common belief Hypatia did not invent the hydroscope, although others believe that Hypatia did help other inventors to build the instrument.
• 4'In 402, Hypatia receives a letter from the ailing Synesius giving a brief description of what he calls a hydroscope.