Portable barometer of the type invented by Jean-André de Luc. The instrument is enclosed in a wooden box with opening front. The two arms of the barometric tube are connected by a metal container fitted with a tap. In transport, the mercury was moved into the longer arm of the barometric tube. The barometric scales are printed on paper and divided into Paris inches. The instrument is fitted with a plumb bob to check its vertical position and a mercury thermometer with Fahrenheit and Réaumur thermometric scales.