Lampas, or Descriptions of Mechanical Improvements of Lamps and Waterpoises

...being very skillfully original: "Artificially" and mechanically performed, the receptacle CC will be raised by the same degrees by which the oil is consumed at E, and its upper surface original: "Superficies" shall always remain in the same horizontal line MM. The geometrical and mechanical reason for this is so very plain that I hope I shall not need to spend any more time in its explanation, other than to say that by means of the Archimedean spiral-fusee original: "Spiral-Fusey"; a conical or spiral pulley used to regulate the force of a weight as it moves, the force original: "Power" of the weight I upon the pulley G decreases in the same proportion as the weight of the oil in the receptacle CC is diminished by its consumption.

The seventh way, then, is by a cylindrical or prism-shaped plug fitted into a matching cylindrical or prism-shaped receptacle. As it is let down into the receptacle by a counterweight original: "Counterpoise" hung upon a spiral fusee, the oil is raised in that receptacle so as to always stand brim-full, or at the same horizontal height, until the entire supply of oil is consumed.

The design of this method will be very easily understood by anyone who shall examine the illustration original: "Delineation" in the eighth figure and study it by this following description.

Let AA in the eighth figure, then, represent a cylindrical or prism-shaped receptacle, standing fixed upon a table or pedestal. From the side of this vessel issues a hollow arm or branch, BB, bearing the socket for the wick, C, where the flame, D, is maintained. Into the cavity of this receptacle is fitted a cylindrical or prism-shaped plug, EE, large enough to fill the entire capacity of the vessel, and yet not so tight that it cannot freely slip up and down the cavity of the receptacle without sinking. Let this plug be made considerably heavier than the oil in the receptacle; that is, let the counterweight L, hanging upon the little wheel M, just balance its weight original: "reduce its gravity" to be equal to that of the oil. Then, let the point I, where the perpendicular line touches the spiral, be so far removed from the center of the wheel H that the counterweight...