In wooden box, some parts missing. With inscription: Dicas patentee. John Dicas was an instrument maker in Liverpool who, in 1780, received British patent #1,259 for “constructing hydrometers with sliding-rules to ascertain spirit strength.” The new form was soon well known in the United States. To pay off the Revolutionary War debt and fund the new American government, the U.S. Congress established a tariff in 1790. The new law described six classes of spirits, ranging from 10% under proof to more than 40% above proof, where proof was understood to mean equal parts alcohol and water. Determination was to be made with a Dicas hydrometer.