azote, combing with a part of the hydrogen, forms ammoniac, or volatile alkali.
Animal substances, being composed nearly of the same elements with cruciferous plants, give the same products in distillation, with this difference, that, as they contain a greater quaintity of hydrogen and azote, they produce more oil and more ammoniac. I shall only produce one fact as a proof of the exactness with which this theory explains all the phenomena which occur during the distillation of animal substances, which is the rectification and total decomposition of volatile animal oil, commonly known by the name Dippel's oil. When these oils are produced by a first distillation in a naked fire they are brown, from containing a little charcoal almost in a free state; but they become quite colorless by rectification. Even in this state the charcoal in the composition has so slight a connection with the other elements as to separate by mere exposure to the air. If we put a quantity of this animal oil, we rectified, and consequently clear, limpid, and transparent, into a bell-glass filled with oxygen gas over mercury, in a short time the gas is much diminished, being absorbed by the oil, the oxygen combining with the hydrogen of the oil forms water, which sinks to the bottom, at the same time the charcoal which was combined with the hydrogen being set free, manifests itself by
