FIG. 96.—Furnace for hardening broaches.
FIG. 97.—Forging and welding furnace.
FIG. 98.—Semi-muffle furnace.
FIG. 99.—Muffle furnace.
Furnaces of these types of oil-burning furnaces are shown in Figs. 97, 98, and 99; these being made by the Gilbert & Barker Manufacturing Company. The first has an air curtain formed by jets from the large pipe just below the opening, to protect the operator from heat.
