the rational, but not self-evident results of geometry and arithmetic. He was impatient of the subtleties of astronomical calculations; they only attempted to satisfy problems about the motion of bodies in the sky, and told us nothing of physical fact; they gave us, as Prometheus gave to Jove, the outside skin of the offering, which was stuffed inside with straw and rubbish. He entirely failed to see that before dealing with physical astronomy, it must be dealt with mathematically. "It is well to remark," as Mr. Ellis says, "that none of Newton's astronomical discoveries could have been made if astronomers had not continued to render themselves liable to Bacon's censure." Bacon little thought that in navigation the compass itself would become a subordinate instrument compared with the helps given by mathematical astronomy. In this, and in other ways, Bacon rose above his time in his conceptions of what _might be_, but not of what _was_; the list is a long one, as given by Mr. Spedding (iii. 511), of the instances which show that he was ill-informed about the advances of knowledge in his own time. And his mind was often not clear when he came to deal with complex phenomena. Thus, though he constructed a table of specific gravities--"the only collection," says Mr. Ellis, "of quantitative experiments that we find in his works," and "wonderfully accurate considering the manner in which they were obtained;" yet he failed to understand the real nature of the famous experiment of Archimedes. And so with the larger features of his teaching it is impossible not to feel how imperfectly he had emancipated himself from the power of words and of common prepossessions; how for one reason or another he had failed to call himself to account in the terms he employed, and the assumptions on which he argued. The caution does not seem to have occurred to him that the statement of a fact may, in nine cases out of ten, involve a theory. His whole doctrine of "Forms" and "Simple natures," which is so prominent in his method of investigation, is an example of loose and slovenly use of unexamined and untested ideas. He allowed himself to think that it would be possible to arrive at an alphabet of nature, which, once attained, would suffice to spell out and constitute all its infinite combinations. He accepted, without thinking it worth a doubt, the doctrine of appetites and passions and inclinations and dislikes and horrors in inorganic nature. His whole physiology of life and death depends on a doctrine of animal spirits, of which he traces the operations and qualities as if they were as certain as the nerves or the blood, and of which he gives this account--"that in every tangible body there is a spirit covered and enveloped in the grosser body;" "not a virtue, not an energy, not an actuality, nor any such idle matter, but a body thin and invisible, and yet having place and dimension, and real." ... "a middle nature between