Description

Mercury-in-glass tar thermometer calibrated from 60 to 200 degrees in a cylindrical casing with flaw holes at the lower end. The glass tube is broken below the index plate. Ring handle at top.

Used for measuring the temperature of tar during the laying process.

A.H. Baird in 1891-92 advertised themselves as a maker of “Apparatus to Special Designs in wood or metal” and gave their address as Science Materials Depot, 15 Lothian Street, Edinburgh (http://www.edinphoto.org.uk/pd/pd_baird_1891.htm.).