AMONG recent publications, we feel called upon to notice "An Essay on Human Understanding," by a certain Locke, of England. The book is evidently to be taken as an extravaganza or philosophical romance, and is designed, by a pleasing species of reductio ad absurdum, to ridicule the philosophers who were opposed to Descartes. Locke's method was probably suggested by the "Historic Doubts" of Whately, and his satire is more complete, if possible, than that of the celebrated divine. By fully presenting and amusingly overstating a system of philosophy he completely undermines the edifice he is supposed to be rearing. The very title of the book is a jeu d'esprit. As if to show the absurdity of knowledge in general, apart from things known, he derisively calls his book "An Essay on Human Understanding," without the article. Nowhere is his satire more crushing or his humor more delightful than in his chapters on innate ideas. In a masterly way he states the arguments so that they confute themselves. He shows that his real opinion is that all ideas are innate, and exposes the fallacy of believing any to be derived from sensation or reflection. Here, as well as elsewhere in his book, he is in strict harmony with Descartes. In fact, he seems to have written to simplify and explain his great master; and though we find nowhere mention of Descartes, we cannot doubt the admiration and assent implied in every paragraph. He is then a Descartes made easy, - a Robinson Crusoe in words of one syllable. In the simplicity and Saxon character of his phraseology he forcibly reminds us of our own humorist, Petroleum V. Nasby, and, in fact, a more elaborate parallel might be drawn between the letters of the Confederate postmaster and this ostensible attack on innate ideas. But, not to make the analogy cruelly walk on five legs, it is enough to say that in his feuilleton Locke has adopted the plain unvarnished language of his prototype. But we must not be misled by the apparent openness of his style. While clear as a spring he is deep as the ocean, and we must read and reread, when the simplicity will resolve itself into the true philosophical confusion. It is admirably adapted therefore for Primary and Grammar Schools, and a few hints on the proper method of shooting the young idea in this direction may be not out of place. To carry out the humorous idea of the book, the instructor should lay down his opinions as decisively and finally as the judge on the bench. He is to assume dogmatism in its most absolute phase, and establish a terrorism over the minds of his pupils. Is it for a learner to state objections? By no means. Shall we doubt anything? Not at all. But, to carry dogmatism to its extreme verge, he is at stated intervals formally to proclaim liberty of opinion and invite freedom of discussion. Having thus forced the whole system of metaphysics upon the young idea, it will incontinently reject all and of course adopt the opposite side, which of course was the thing aimed at.

The poetical nature of the book is also to be noticed, which is a rare merit in a work of this nature. The divinus afflatus has rarely inspired a man to indite odes to his mother-in-law, and almost as rarely does the gentle muse of poetry venture over into the stern and barren fields of philosophy. It has been said that Locke only needed rhyme to become a poet. We submit respectfully to the author the propriety of turning his work into a metrical form. To revel in a lyric on the "Complex Modes of Extension or Duration and Expansion as measured by Number"! His metaphors are abundant, and show that he had a constant struggle to keep his poetical nature in restraint. His comparison of a sleeping man to an oyster or cockle, his simile in regard to the brains, - that some retain impressions like marble, others like sandstone, others like sand, - and his chemical metaphor about the flames of a Bunsen burner calcining the images impressed on the memory to dust, are fine examples of his wildly poetical temperament. But we must not forget his celebrated figure which made such an impression on us that we remember it in full, and will quote: "The ideas of our youth, like the good children in Sunday-School books, die young, and though cremation be preferred to the vain show of tombs and monuments, and the brass and marble fade away, the location of the spot is plainly indicated by a sprig of forget-me-not." (Vol. I. p. 266.)