Kant's preoccupation with architectonics is a characteristic and noteworthy aspect of his thought. Various features of Kant's argumentation and philosophical system are founded on the precise definitions of the various subdomains of human knowledge and the derivative borders among them. One science conspicuously absent from Kant's routine discussions of the organization of knowledge is chemistry. Whereas sciences such as physics, psychology, and anthropology are all explicitly located in the architectonic, chemistry finds no such place. In this paper, I examine neglected passages from Kant's corpus as well as texts regarding chemistry that Kant himself read in order to unveil his views on the definition of chemistry and its relations with the other sciences. These considerations reveal chemistry to be the science that studies the changes of matter into new kinds. Yet Kant idiosyncratically believes that such a change requires an infinite division of matter, effected by chemical forces. Although this understanding of chemical change dovetails with Kant's dynamical, continualist theory of matter, it implies that chemistry cannot be reduced to physics. Thus, although chemistry stands alongside empirical physics as an applied natural science in Kant's architectonic, it remains a distinct, independent science.