auditory nerve float, and by this nerve the sensation is cou veyed to the brain. See also ACOUSTICS.

3. Smelling. The cavity of the nose is divided into two parts, called the nostrils, by a partition, of which the upper part is bony, and the lower cartilaginous. The upper part of the cavity is covered with a thick glandulous membrane, above which the olfactory nerve is finely branched out and spread over the membrane of the spongy bones of the nose, and other sinuous cavities of the nostrils. The odorous effluvia of bodies being disseminated in the atmosphere, the latter fluid passes through the nose in respiration, and the odorous particles are thus brought iuto contact with the fibres of the nerves, which, by their communication with the brain, excite in the mind the sense of smell.

4. Tusting. The tongue is covered with two membranes: the external is thick and rugged, especially in quadrupeds; the internal membrane is thin and soft; upon it appear several pupillæ, or small elevations, like the tops of the small horns of snails. These papillae are composed of the extremities of the nerves of the tongue, and piercing the external membrane, are constantly affected by those qualities in bodies, which have their tastes excited in the mind by means of these nervous papillæ, which are the immediate organ of tasting. This organ bears a considerable analogy to the sense of touch.

5. Touching. The outside of the skin is covered by a thin pellicie, called the epidermis, cuticle, or scarf-skin. Under the cuticle, is a substance called the rete mucosum. In negroes, this substance is of a black colour, but in Europeans, white, brown, or yellowish. The cutis vera, or the skin, is a substance made up of fibres closely connected with each other, and running in various directions, being composed of the extremities of numerous vessels and The papilla of the fingers or inside of the hand, may become erect or elevated, and being gently pressed against a tangible body, receive an impression which is conveyed to the brain, and is called touch.

nerves.

ANATOMY, which considers minutely the structure and functions of the human body, is divided into, 1. Osteogeny, or the doctrine of the growth of bones. 2. Osteology, or the doctrine of the matured bones. 3. Chondiology, which

treats of cartilages. 4. Syndesmology, which treats of ligaments. 5. Myology, or the doctrine of the muscles. 6. Bursalogy, which treats of the bursæ mucosæ. 7. Splanchnology, or the doctrines of the viscera. S. Angiology, which treats of the vessels. 9. Adenology, of the glands. 10. Neurology, or the doctrine of the nerves, &c.

Select Books on the Animal Kingdom.

Dr. SHAW's highly accurate and splendid work entitled, General Zoology, and his valuable Lectures on this subject delivered at the Royal Institution. The General Zoology is unequalled for the elabo rate fidelity of its descriptions, the beauty and accuracy of the plates with which it is embellished, and for the splendour of its typography. The Zoological Lectures deserve to be generally read, and are an admirable introduction to the larger work, which is not yet brought to a conclusion. To both these works we are proud to confess our obligations.

Dr. Shaw's Naturalist's Pocket-Book, a pleasing and instructive annual companion. Bingley's Animal Biography, 3 vols. 8vo. British Zoology, and Memoirs of British Quadrupeds, 8vo. Bewick's Quadrupeds, 8vo., and Birds, 2 vols. 8vo. Derham's Physico and AstroTheology, 2 vols, 8vo. a new edition, with notes. Lesser's InsectoTheology, with Lyonnet's notes, 8vo. Paley's Natural Theology, 8vo.

1.

Natural Philosophy.

It is T is to the old alchemists, or to those who were engaged in whimsical and visionary attempts to discover the philosopher's stone, that we are ultimately indebted for philosophy. They engaged in various chemical processes or experiments, in order to effect this grand discovery; and from their patient and laborious endeavours, many useful inventions proceeded, though not the particular discovery they were in quest of. Our countryman, ROGER BACON, a famous monk who resided at Oxford in the twelfth century, was one of these, but he was one of the most rational and sagacious of the whole sect. He was soon convinced of the difficulty of the research in which he was engaged, (that of transmuting or changing other metals or substances into gold;) but he saw that the mode of analyzing or dividing bodies or substances into their constituent parts, was the true mode of investigating

nature.

2. TO LORD BACON philosophy is indebted for its next great improvement. He followed the footsteps of his name-sake and predecessor; he reduced his principles to a system, and laid it down as a maxim, that it was by experiment alone, that any thing in philosophy could be known with certainty. He therefore traced out the way in which future experimentalists might proceed, and afforded a variety of hints, on which they afterwards improved.

3. The good and the illustrious BOYLE, however, may justly be termed the father of modern philosophy. He made it a principle to conduct all his inquiries by experiment alone. He effected much in the analyzation of bodies, and the examination of the principles of which they were composed. He not only invented that curious and useful instrument, the air-pump, but his experiments on the nature of air, laid the foundation for all the modern doctrines concerning it. His discoveries on light and colours, were an excellent introduction to the grand theory of NEWTON on that subject, and, possibly, served as the basis or foundation of them. In short, there was scarcely a topic of natural philosophy to which he did not lend his attention, and there was scarcely one which he did not improve.

4. He proposed to substitute experiment for theory, and laid the foundation of a solid edifice of human knowledge, which should rise in due proportion and regular order, from earth to heaven. In his Advancement of Learning,' he laid down the principles of genuine philosophy. The design of the Novum Organum' was, to raise and enlarge the powers of the mind, by a useful application of reason to all the objects which philosophy considers. In order to preclude objections drawn from the supposed visionary nature or novelty of his system, Lord Bacon treats in the third part of his instauration on the Phenomena Universi. This is intended to form a collection of materials towards natural and experimental history.

5. Such was the state of philosophy when NEWTON appeared. He reduced into one grand system, all the scattered discoveries of his predecessors. He explained the motions of the heavenly bodies, on a principle entirely new;

and invented that beautiful planetary system, which is universally received. He developed, with mathematical precision, all the phenomena of light and colours, the nature of vision, and the use of optical glasses and instiuments, which last, he greatly improved. To conclude, he gave body and consistency to natural philosophy, and made it what it never was before, a system of truth, illustrated and proved by experiment.

CHAP. I.-MECHANICS.

MECHANICS treats of the laws of the equilibrium

and motion of solid bodies; of the forces by which animate or inanimate bodies may be made to act upon one another; and of the means by which these inay be increased. It is usually subdivided by scientific writers into Statics and Dynamics, the former relating to the mutual action of bodies at rest, the latter to the action of bodies in motion. Hence, under statics, is comprehended the doctrines of simple machines in a state of equilibrium, the properties of the centre of gravity, the strength and stress of various substances, the pressure of arches and domes, the stability of piers, and the scientific construction of roofs and centering: while under dynamics, philosophers treat of rectilinear, rotatory, and orbitual motion, the oscillation of pendulums, the force of gyrating or revolving bodies, the motion of bodies exposed to the action of centripetal or centrifugal forces, and the maximum effects of machines. 1. The science of mechanics is dependent upon the power which gravity and the laws of motion have on matter. The axioms, or laws of motion and rest, as first laid down by Sir Isaac Newton, are: 1. Every body perseveres in a state of rest, or of uniform rectilinear motion, until a change is effected by some external cause. 2. Every motion, and every change of motion, is proportional to the force impressed, and in its direction. 3. Action and reaction are equal and contrary. These laws, though they are called axioms, are by no means self-evident. The best illustrations and confilmations of them we remember to have seen, are given by MR. ATWOOD in his treatise on Motion, and by DR. GREGORY in the first volume of his comprehensive treatise of Mechanics. Matter comprizes whatever is extended and

capable of making resistance; hence because all bodies, whether solid or fluid, are extended, and do resist, we conclude that they are constituted of matter. Every thing which is the object of our senses, is composed of matter differently modified. Thus, for instance, water rarefied by heat, becomes vapour; great collections of vapours form clouds; these condensed, descend into the form of hail or rain; part of this collected on the earth constitutes rivers; another part mixing with the earth enters into the roots of plants, and supplies matter to, and expands itself into various species of vegetables.

2. It is very probable that all the variety we observe in matter, arises from the various forms and shapes it puts on. Sir Isaac Newton is of opinion, that God in the beginning formed matter into solid, massy, impenetrable, moveable particles or atoms of such sizes and figures, and with such other properties, and in such proportion to space, as most conduced to the end for which he formed them; and that these primitive particles being solids, are incomparably harder than any porous bodies compounded of them, even so hard as never to wear or break in pieces; no ordinary power being able to divide what God himself made one in the first creation. The essential properties of matter, are solidity, divisibility, mobility, and inertia, or a state of inaction.

3. The solidity of matter is not here considered as opposed to fluidity, but as that property which every body possessess of not permitting any other substance to occupy the same place with it at the same time; so that both water and air, and every other fluid are equally solid, in this sense with the hardest body. Solidity, in this sense, is equivalent to impenetrability. A tube filled with water will not admit a plunger accurately fitted to it, unless the water is first displaced. The solidity of matter is manifest by the resistance it makes to the touch. By divisibility, the particles of all bodies are capable of a separation, or disunion from each other. The atoms of which bodies are formed, are concealed from us by their minuteness, and though they are the active parts of matter, we can form no idea of them, for whether we view animate or inanimate matter, the corpuscles of which it is formed, are so infinitely small, as to escape the scrutiny of the highest mag