active 1876-1901, thermometer & hydrometer maker, Nenhaus am Rennwig, Thüringen, Germany Haak, William 1836 - 1898
active 1839-1913, optician, mathematical, barometer, thermometer, hydrometer maker, London, British J. Somalvico and Co.
active 1845-1846, optician, hydrometer, barometer and thermometer maker, London, British Ronketti, John George Harris
active 1790-1940, hydrometer & mathematical instrument maker, optician, London, England Dring and Fage
