in natural history, a fluid mineral body, of a thin consistence, bright and pellucid, of a strong smell, very readily inflammable, and, when pure, burning away without leaving any residuum.

The naphtha is found in considerable quantities floating on the water of certain springs, principally breaking out at the sides of hills in Persia, Tartary, and some parts of the empire of China; where, if a lighted candle be held near the surface, it takes fire and overspreads the surface of the water for a great extent with a strong white flame, and emits a very disagreeable smell. The genuine naphtha is very rare in Europe; it is not known to be anywhere naturally produced here, and what we see of it is generally sophisticated. Distilled by the retort, it yields an oil somewhat thinner than it was originally, and of a weaker smell. The substance remaining at the bottom of the retort, has much the resemblance of amber; and Dr Hill thinks it highly probable, that the origin of all the amber is from the same sort of principle; nay, he tells us that he has succeeded so far in an attempt to make amber by this fluid and an acid drawn from the crude pyrites, that he has produced a friable, somewhat pellucid matter, having all the properties of amber except the hardness and cleanness, and yielding a true fat and oil of amber on distillation. The medicinal virtues of the naphtha are the same with that of the common petroleum, but in a lower degree. It is used externally on many occasions in Persia; and is taken inwardly, a few drops for a dose, in colics. The principal use of it, however, is for burning in lamps; and for this it is extremely well adapted.