Page:Lavoisier-ElementsOfChemistry.pdf/143

 place, by the plan which I have laid down, of proceeding only from facts already ascertained, to such as are unknown, and of drawing my examples only from circumstances already explained. In the mean time, however, the three examples above cited may suffice for giving a clear and accurate conception of the manner in which acids are formed. By these it may be clearly seen, that oxygen is an element common to them all, which constitutes their activity; and that they differ from each other, according to the nature of the oxygenated or acidified substance. We must therefore, in every acid, carefully distinguish between the acidifiable, base,acidifiable base, [sic] which Mr. de Morveau calls the radical, and the acidifiing principle or oxygen.