Hydrometer
From the collection of National Museum of American History. Free to download, adapt and use — no permission needed.
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 <i>Journal of Natural Philosophy, Chemistry and the Arts</i>—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.
National Museum of American History’s own description
