understanding grows to the meaning and right use of the language of the world around him, nor must he complain of difficulties and impediments. Happy the learner, however, who is in the hands of judicious guides, who consider terms subsidiary to instruction in things, with whom books are, as they assuredly ought to be in physical science, not the substitutes for the companionship of nature, but the aids to interpret her lessons, and to observe and to arrange her instructions. The botanist must keep in the fields and the garden; the chemist in the laboratory; the geologist in the quarry, by the hill side or under the cliff; the astronomer must sweep the heavens with his glass, and report to others

Of fields of radiance, whose unfading light Has travell'd the profound six thousand years, Nor yet arrived in sight of mortal things." And it is the beauty of physical science, when legitimately and lovingly pursued, that it calls us into communion with the Creator as he reveals himself in his works, and away from the perverse disputes and vain jang

lings of men. In physical science there is comparatively little of tiresome useless argumentation; the facts on which the classifications and conclusions rest are evident to those senses of whose use not even the Fall has deprived the children of Adam. And though the senses may sometimes deceive us from a kind of natural difference in keenness or constitutional imperfection, or through hasty inferences and casual associations, yet the philosopher who builds his system of science, physical or metaphysical, upon other ground, who thinks the root of the tree of life and knowledge is not in that plain but all-supporting soil, had better return at once to the speculations of the schoolmen, and puzzle himself with inquiries into the necessary attributes of spirits that have never inhabited a body, or dilate upon that pleasant and edifying subject, chimæra bombinans in vacuo.”

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Vanity, partiality for their own habits of study, and their own modes of classification, may even in physical science lead men to differ widely and warmly; but the differ

ence will hardly be very sore, if unconnected with any worldly interests. Questions of fact, and questions of the meaning of terms in most matters of pure science, would be settled without length of debate, if men did not wish to appear wiser than they are; if they were content patiently to learn and mildly to instruct; if they sought the knowledge and love of nature rather than the estimation of men; if they looked upon themselves as mutual interpreters, and mutual servants of the will of Him, who has made of one blood all nations of the earth to dwell together upon its face, and bound the vast family of man together by the strongest ties of mutual interest, making it their chief and noblest happiness to benefit and assist each other.

In the pursuit of physical science it would be very easy to repeat some of the principal rules to be observed; but they are already in various forms and in abundance before the studious and inquiring world. To observe and register carefully, not to generalize too fast, to take special care of your premises before you arrive at your conclusions, to build the super

structure of system upon the solid groundwork of clear and well-ascertained facts, and with the strong masonry of well-defined and chastised language-the cement of human knowledge-these are the short and simple, but universal rules for all philosophy. The Novum Organum of Bacon; the first of the preliminary dissertations prefixed to Buffon's Théorie du Monde; the admirable Reflexions sur la Geométrie, in the Pensées de Pascal; Hartley's invaluable Observations on Propositions and the Nature of Assent; the last book of Locke's Essay on the Human Understanding; Herschel's Treatise on the Study of Natural Philosophy; Dr. Whately's Logic; some of the remarks of Laplace, in his Essay on Probabilities, to which I shall hereafter advert, and of Cuvier in the Preface and Introduction to his Animal Kingdom; and Mr. De Morgan's treatises published by the Society for the Diffusion of Useful Knowledge;-are among the works of most importance in connexion with the subject of this Essay. The following passage from the preface to Cuvier's first edition of his Règne

Animal will be acceptable to the reader who is not previously acquainted with it, and bears closely upon our present course of thought. "The habit necessarily acquired in the study of natural history, of the mental classification of a great number of ideas, is one of the advantages of that science which is seldom observed, and which, when it shall have been generally introduced into the system of common education, will become perhaps the principal one. By it the student is exercised in that part of logic which is termed method, just as he is by geometry in that of syllogism; because natural history is the science which requires the most precise methods, as geometry is that which demands the most vigorous reasoning. Now this art of method, once well acquired, may be applied with infinite advantage to studies the most foreign to natural history. Every discussion implying a classification of facts, every inquiry which demands a distribution of materials, is performed according to the same laws; and the young man who had cultivated this science merely for amusement, is surprised,