Ramsden's balance, late 18th century.
© Science Museum / Science & Society Picture Library
Jese Ramsden (1735-1800) was an English instrument maker, who improved optical and survey instruments. During the 18th century, work commisioned by the British Government and the Royal Society required accurate measurement of the specific gravity of water-alcohol mixtures, in order to levy taxes in a scientific manner. Hence, Ramsden was given the task of developing a balance with a high level of sensitivity and accuracy, although each measurement took a very great time to take.