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"The moderator lamp, invented by M. Franchot about 1836, from the simplicity and efficiency of its arrangements rapidly superseded about all other forms of mechanical lamps. The two essential features of the moderator lamp are (1) the strong spiral spring which, acting on a piston within the cylindrical reservoir of the lamp, serves to propel the oil to the burner, and (2) the ascending tube C through which the oil passes upwards to the burner. The latter consist of two sections, the lower fixed to and passing through the piston A into the oil reservoir, and the upper attached to the burner. The lower or piston section moves within the upper, which forms a sheath enclosing nearly its whole length when the spring is fully wound up." —The Encyclopedia Britannica, 1910

Moderator Lamp

"The moderator lamp, invented by M. Franchot about 1836, from the simplicity and efficiency of its arrangements…