The hydrometer was probably used for home brewing or by someone at work. A hydrometer was used for measuring specific gravity (how heavy a liquid is compared to water) in alcoholic drinks and other liquids. Nowadays hydrometers are made out of glass but then, in the 19th century, they were made out of brass. It would tell the brewer about the alcoholic strength. This old object tells us about technology in the 19th century in Buckhurst Hill. Buckhurst Hill was famous for the beer industry in England. The Lee Navigation would transport coal to fire the kilns of the maltings in Hertford and Ware which produced the malt for the beer. In nearby Romford there is a big chimney that says 'The Brewery' which used to be used in an actual brewery.