of scientific truth, that he repeatedly opposes all systematization of science, and in his Natural Philosophy followed his own precepts. In the Advancement of Learning he says: “As young men, when they knit and shape perfectly do seldom grow to a further stature, so knowledge, while it is in aphorisms and observations, it is in growth; but when it is once comprehended in exact methods, it may perchance be further polished and illustrated, and accommodated for use and practice; but it increases no more in bulk and substance.” And again he remarks: “The worst and most absurd sort of triflers are those who have pent the whole art in strict methods and narrow systems, which men commonly cry up for their regularity and style.” In illustration of this we may adduce Whewell’s celebrated works, The History and Philosophy of the Inductive Sciences. Here are great learning, logical arrangement, a complete superficial comprehension of the whole subject; but life is wanting. Most of the great discoveries and inventions with which such a book would naturally deal have been made since the publication of Bacon’s Novum Organon; but more mental nutriment and inspiration, more to advance the cause of science, can be found in one page of the Novum Organon than in Whewell’s whole five volumes. Such is the difference between a vital and mechanical mind in the history and philosophy of science; and the difference is more observable still when we come to consider the deep and constant enthusiasm, the persisting, penetrating genius of the practical discoverer, as contrasted with the cold and uncreative memory-monger and reasoning machine, who too often passes himself off as the real _savant_. The only great man of science who has detailed his processes in connection with his emotions is Kepler, and everybody has heard of the “sacred fury” with which he assaulted the fortresses in which nature long concealed her laws. His page flames with images and exclamations. His operations to conquer the mystery in the motions of the planet Mars are military. His object is as, he says, “to triumph over Mars, and to prepare for him, as one altogether vanquished, tabular prisons and equated eccentric fetters.” When “the enemy left at home a despised captive, had burst all the chains of the equations, and broken forth of the prisons of the tables,” and it was “buzzed here and there that the victory is vain,” the war rages “anew as violently as before,” and he “suddenly brings into the field a new reserve of physical reasonings on the rout and dispersion of the veterans.” A poet can thus vitalize mathematics, and “create a soul under the ribs” of physical death.