This vintage industrial thermometer was manufactured by the renowned scientific instrument maker G.H. Zeal of London, England. Specifically designed for confectionery and sugar boiling, it features specialized stage markings (such as caramel, crack, hard ball, soft ball, and water boil) to assist confectioners in precise temperature monitoring. Housed in a heavy brass frame with an integrated hanging ring, it exemplifies durable mid-20th-century British scientific craftsmanship. Shows authentic vintage age and industrial wear with expected surface patination, tarnish, and minor spots of discoloration to the brass housing. The glass tube and white-backed scale remain intact and clear, with legible markings throughout. Dimensions: 33cm (L)