Barometer, supplied by J.J. Hicks

Jean Nicolas Fortin (1750-1831) devised the barometer which became standard for scientific purposes during the 19th century, and became known as the 'Fortin barometer'. In about 1800, he made the instrument more accurate by arranging a glass wall in the reservoir through which could be seen the mercury level and an ivory pointer. The tip of this was exactly the zero point of the inch (or millimetre) scale seen on the register plates at the top of the instrument, and the level could be compensated for temperature. It was also easy to transport.

This is a Fortin barometer in black-painted cast iron, with glass-walled cistern and brass fittings. By using a vernier, readings on the scale can be taken to fractions of an inch or millimetre, with great accuracy. This instrument is marked with the supplier's name, J.J. Hicks of London.

This design of barometer proved successful throughout the 19th century. The glass barometer tube, containing boiled mercury (so no air was trapped in it), was enclosed and protected by a brass tube, the upper part having two long openings on opposite sides to allow readings to be made. The glass-walled cistern reservoir had a leather bag underneath, which could be adjusted by the screw at the base.

Record details

To search on related items, click any linked text below.