oil-tester

from The Century Dictionary.

• noun A machine for testing the lubricating properties of oils.
• noun A process or an apparatus for ascertaining the temperature at which the vapors from mineral oils will take fire.
• noun It consists of a copper vessel, A, serving as a water-bath in which a second copper vessel, B, containing about 10 ounces of the oil, is placed. The water is heated at the rate of 20° F. per minute by a small alcohol or oil flame, C. The temperature of the oil is noted by the aid of a thermometer supported by a glass plate which covers the oil except at one point where an opening is left for the insertion of a small flame such as a lighted broom-splint or match-stick would give. When the oil has reached 85° F., testing is begun by applying a flame at the opening. When a flash of blue flame is seen over the surface of the oil, the reading of the thermometer is taken. Generally a flash-test of 100° F. is required by law.