American Barometer by James Green of Historic Interest

Labelled Jas. Green New York.Mid 19th century40in.After organizing a national Weather Service, the Smithsonian Institution commissioned James Green to make instruments suitable for distribution around the country. This portable mercury barometer, is of that sort. It has a sliding vernier operated by a head screw at the top of the tube, a Fahrenheit thermometer in the side of the tube, and a thumb screw that adjusts the volume of the cistern