Advertisement for Sikes's Hydrometer, 19th century.
© Science Museum / Science & Society Picture Library
Advertisement for Sikes's Hydrometer, manufactured by Joshua Long, consisting of an image of the hydrometer with accompanying text. Hydrometers are used to measure the relative density of a liquid and are particularly used for establishing the alcoholic content of liquids. A hydrometer will float higher in a heavy liquid, such as one that has a high quantity of sugar. A les heavy liquid, where the sugar has been turned into alcohol, will make the hydrometer float lower. Sikes's Hydrometer is covered with a body of fine gold to help prevent corrosion. Long also boasts that Sikes's Hydrometer is small enough to fit into a waistcoat pocket. Hydrometers are still used in wine making today.