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William Nicholson (1753-1815) was a science enthusiast in London who, in 1790, mentioned his attempt “to adapt the hydrometer to the general purpose of finding the specific gravity, both of solids and of fluids,” and published a picture of this instrument. In 1797, in the second issue of the first volume of the Journal of Natural Philosophy, Chemistry and the Arts—a publication that Nicholson established and edited—there was an article by the French chemist, Guyton de Morveau, describing a hydrometer that Nicholson had designed several years earlier. In time, Nicholson’s instrument would be termed a gravimeter, a portable balance, or a hydrostatic balance. The U.S. Military Academy acquired this example ca. 1835-1844. The maker is unknown.
Ref: William Nicholson, An Introduction to Natural Philosophy (London, 1790), vol. 2, pp. 13-16, and fig. 123.
Citizen Guyton, “Description of a Gravimeter, or Instrument for measuring the Specific Gravity of Solids and Fluids,” Journal of Natural Philosophy, Chemistry and the Arts 1 (June 1797): 110-119, and plate 6.
Currently not on view
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hydrometer: 9 in x 2 3/4 in; 22.86 cm x 6.985 cm
overall: 3 1/2 in x 3 3/4 in x 9 3/4 in; 8.89 cm x 9.525 cm x 24.765 cm
overall in box: 3 5/8 in x 9 7/8 in x 3 13/16 in; 9.2075 cm x 25.0825 cm x 9.68375 cm
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National Museum of American History
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This gravimeter is identical to one in a private collection which in the case bears the retailer’s label for Richard & George Knight, Foster Lane, London. The writer suspects that this and the Smithsonian instrument were made by the renowned hydrometer maker R B Bate whose workshop was near Foster Lane. A similar instrument, signed by Bate, is in the collection of the History of Science Museum at Oxford (UK), inventory number 43394. It is illustrated in "R B Bate of the Poultry 1782-1847" by Anita McConnell.

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