Lampas, or Descriptions of Mechanical Improvements of Lamps and Waterpoises

[The vapors] burn, but are as it were charred original: "charkd" by the extreme heat of the conical surface original: "Conical Superficies" of the flame. They are protected from burning at the bottom by the constant flow of new oil from the vessel underneath; and the middle parts are protected from burning or shining because the air cannot reach them before it is saturated at the conical surface i i i by the dissolution of the oil vapors original: "steams" it meets there.

However, the upper parts of the wick do burn and shine if they are high enough to reach into the narrower part of the cone of flame where the air can reach them before it is saturated. If any part of the wick falls into this conical and shining surface of the flame, it both shines and is consumed, undergoing the same dissolution into the air as the oil vapors. Furthermore, if any part of this wick is outside this conical surface at i i i, it is immediately consumed and reduced to ashes; as is clearly visible through many experiments made in different ways.

This clearly explains why knots and tophi original: "Tophus’s"; in this context, the author refers to the hard, crusty carbon deposits that form on a wick. seem to grow on the wick of the lamp like mushrooms on a rotten tree. As soon as they are moved out of the middle and "dead" part of the flame, they are immediately consumed by and dissolved into the air, shining like a coal of fire—which is exactly what they are.

From this, we can give a clear reason why, upon placing any cool surface very low into the flame of a lamp, a large quantity of soot immediately condenses upon it. Specifically, the middle parts of the cone of flame consist of nothing but a vast number of rising oily vapors. These are not ignited or consumed by the air until they can be acted upon by free and unsaturated air. Now, if the air is blocked so that it cannot reach them, and the vapors are cooled by the plate's coldness so that the air is unable to prey upon or dissolve them for lack of sufficient preparatory heat, they must remain in the form of burnt oil or lampblack.

I have been somewhat the longer and more particular in...