 Spinoza in fact agrees with Boyle that the scholastic view is bankrupt, but he rejects Boyle's claim that the separation of the nitre into two parts is actually a decomposition of a distinctive substance into two others; rather, he claims that the experiment is consistent with the Cartesian view, itself based on reason, that differentiations among extended substance are always owing to different quantities of motion and rest. He claimed that the ”fixed nitre“ (potash) was actually an impurity mixed into the original sample, and that the spirit of nitre was simply the volatile state of the pure, crystallized nitre portion of the original mix. Thus the different chemical properties of spirit of nitre and the original sample owe not to a difference of substantial structure—the basic shape of the particles of each is the same—but to a difference in their motion. In support of this reading and against Boyle's interpretation, Spinoza claimed that, if Boyle were actually to show what he claimed, ”further experiment seems to be required to show that Spirit of Nitre is not really Nitre, and cannot be reduced to solid state or crystallized without the help of salt of lye“ (Letters, p. 71). Spinoza then went on at some length to show how, in the absence of such a demonstration, it is easy enough to explain the results of Boyle's experiments along Cartesian lines. He further explains several experiments he himself performed which he takes to support the Cartesian interpretation, claiming that he ”might have added further experiments which would perhaps make the matter quite clear“ (Letters, p. 76).