Elegant cistern barometer mounted on a wooden base with glass windows. An ivory floating weight with reference index is inserted in the cistern; a screw underneath it adjusts the level of the mercury by acting on a leather membrane. The barometric scale, in English inches, is fitted with a vernier. There is also a mercury thermometer with a Fahrenheit scale and recording pointer, and an oat's-beard hygrometer calibrated by means of a handle. Made by Nairne & Blunt.