 Other items on his list were remnants of the Aristotelian system which have no place at all in the modern system. For example, fire remained on his list, although in the somewhat altered form of caloric. Air is analyzed into several components: the respirable part called oxygen and the remainder called azote or nitrogen. Four types of earth found a place on his list: lime, magnesia, barytes, and argill. The composition of these earths are “totally unknown, and, until by new discoveries their constituent elements are ascertained, we are certainly authorized to consider them as simple bodies” (1789, p. 157), although Lavoisier goes on to speculate that “all the substances we call earths may be only metallic oxyds” (1789, p. 159).