Page:Lavoisier-ElementsOfChemistry.pdf/193

 C H A P. XI.

Observations upon Oxyds and Acids with several Bases--and upon the Composition of Animal and Vegetable Substances.

e have, in Chap. V. and VIII. examined the products resulting from the combination of the four simple combustible substances, sulphur, phosphorus, charcoal, and hydrogen: We have shown, in Chap. X that the simple combustible substances are capable of combining with each other into compound combustible substances, and have observed that oils in general, and particularly the fixed vegetable oils, belong to this class, being composed of hydrogen and charcoal. It remains, in this chapter, to treat of the oxygenation of these compound combustible substances, and the show that there exist acids and oxyds having double and triple bases. Nature furnishes us with numerous examples of this kind of combustions, by means of which, chiefly, she in enabled to produce a vast variety of compounds from a very limited number of elements, simple substances. I: