simply for the purpose of obtaining a knowledge of their order, their arrangement, and the disposition of their parts, without referring effects to their causes, it is termed Particular Physics, or i Natural History. It thus appears, that while Natural Philosophy is the ultimate object of science, Natural History is the source whence all science must necessarily arise. The former is unrivalled for sublimity of ideas and depth of investigation, the latter for variety of character and interest in its details. While Natural Philosophy is best fitted to occupy the mind in its severer moments, Natural History affords an agreeable relief, by the general beauty of its objects, the elegance of their forms, the richness of their colouring, the singularity of their habits and instincts, and the exquisite adaptation of all their parts. Both alike lead us to form elevated and enlightened conceptions of the power and beneficence of the Creator.

GENERAL PHYSICS examines, in an abstract manner, each of the properties of those moveable and extended bodies, to which we apply the general term matter.

That branch called Mechanics considers the particles of matter as collected in masses, and deduces mathematically, from a very small number of experiments, the laws of equilibrium, of motion, and of its communication. Its several divisions take the names of Statics, Dynamics, Hydrostatics, Hydrodynamics, Aerostatics, &c., according to the nature of the bodies, the motions of which are under examination.* Optics considers solely the peculiar vibrations of light; but in this science various phenomena, ascertained entirely by experiment, are daily becoming more numerous. Chemistry, the other division of General Physics, explains the laws, by which the elementary particles of bodies act on each other, at indefinitely small distances; the combinations or decompositions resulting from the affinity of their ultimate elements; and the manner in which the operation of affinity is modified by various circumstances, capable of increasing or diminishing its action. Being chiefly an experimental science, it cannot, on that account, be classed with others more exclusively mathematical.

The theories of heat and electricity may belong almost equally to Mechanics or to Chemistry, according to the point of view in which each of them is considered.

The mode of proceeding adopted in all the departments of General Physics is, to consider, either mentally or experimentally, only a small number of the properties of bodies at once, in order to reduce them to the greatest attainable simplicity; then, to calculate or discover the effects resulting therefrom; and finally, to generalize and incorporate the laws of these properties so as to form series of theorems; and, if possible, to resolve them into one universal principle, which will serve as a general expression for them all.

PARTICULAR PHYSICS, or Natural History (for both of these terms are used indiscriminately), may [be extended so as to include the particular application of the laws, ascertained by the different branches of General Physics, to the numerous and diversified created beings existing in nature, in order to explain the phenomena which each exhibits. When used in this extensive signification, it also includes Astronomy; but this latter science, being fully elucidated by the light of Mechanics alone, is entirely subservient to its laws, and employs methods of investigation, too different from those admitted by Natural History, to be [extensively] cultivated by the same persons. It is usual, also, to include Meteorology among the branches of General Physics, and to confine Natural History to objects which do not admit of rigorous mathematical investigation, or precise measurement in all their parts.

Geology ranks next to Astronomy for the sublimity and depth of its investigations, and ought, logically, to be classed with Natural Philosophy. But the science is based upon so vast a mass of historical detail, and is still so much in its infancy, that it will long continue to be arranged with the branches of Particular Physics. It contrasts with Astronomy in this respect, that while the last-mentioned science leads us to explore the infinity of space, Geology unfolds the secrets of the infinity of past time. In the one, the present place of man is considered but as a point in the vast regions of space; in the other, the present time but as an instant in the middle of two infinities -time past and time to come.

NATURAL HISTORY properly considers only the inorganic bodies called Minerals,

* In this, and in similar passages, we have thought it more agreeable to received usage to transpose the terms Mechanics and Dynamics from the position in which they stand in the original, the former being, as we conceive, the more general term.-Translator.

and the various kinds of living beings [called Animals and Plants], almost all of which are under the influence of laws, more or less unconnected with those of motion, of chemical affinity, and of various others, analyzed in the several departments of | General Physics. We ought, in treating of Natural History, to employ precisely the same methods as in the General Sciences; and, therefore, we endeavour to adopt them, whenever the subjects under examination become sufficiently simple to permit that mode of investigation. But as this is seldom practicable, there arises, hence, an essential difference between the General Sciences and Natural History. For, in the former, the phenomena are examined under circumstances completely within the reach of the inquirer, who arrives, by analysis, at general laws; while, in the latter, they are removed, by unalterable conditions, beyond his control. In vain he attempts to disengage them from the influence of general laws, already ascertained. He cannot reduce the problem to its elements, and, like the experimental philosopher, withdraw successively each condition; but he must reason upon all its conditions at once, and only arrive, by conjecture, at the probable result of such an analysis. Let him seek to ascertain, by direct experiment, any one of the numerous phenomena essential to the life of an animal, though but slightly elevated in the scale of being,

"And ere he touch the vital spark-'tis fled."

Thus, it appears that, while Mechanics has become a science chiefly of CALCULATION, and Chemistry of EXPERIMENT, Natural History will long remain, in most of its departments, a science wholly of OBSERVATION.

The latter part of this remark must, however, be restricted to the early stages of Natural History; because, in its more matured condition, it becomes a science of demonstration. Every branch of physics has one leading object in view, and that is, the discovery of the ultimate laws of Nature. Philosophy regards this as of primary importance; while utility is held only as of secondary rank. Science, in its most comprehensive sense, is a superstructure founded on facts, or acquired by experience; and hence, in its early stages, we consider it as entirely limited to observation: but when we have learned to generalize, and find that truths agree in their several relations, we have arrived at the demonstrative part of the science. It is not, therefore, from a mere knowledge of correct nomenclature, or from a capacity to recognise at sight a natural object, that we are entitled to apply the name of scientific knowledge to Natural History; but only when we have succeeded, by observation, in deducing the laws which regulate these objects, in their relations to surrounding beings.

These three terms, Calculation, Observation, and Experiment, express, with sufficient accuracy, the manner of cultivating the several branches of Physical Science; but, by exhibiting among them very different degrees of certainty, they indicate at the same time, the ultimate point to which Chemistry and Natural History ought to tend, in order to rise nearer to perfection. Calculation, in a manner, sways Nature: it determines the phenomena more exactly than can be done by observation alone; Experiment obliges Nature to unveil: Observation watches when she is refractory, and seeks to surprise her.

Natural History employs with advantage, on many occasions, a principle of reasoning peculiar to itself, termed the conditions of existence, or, more commonly, final causes. As nothing can exist except it contains within itself all the conditions which render existence possible, it is evident, that there ought to be such a mutual adaptation of the various parts of each being among themselves, and such an accommodation of their structure to the circumstances of surrounding beings, as to render possible the existence of the whole. The analysis of these conditions often leads to the discovery of general laws, with a clearness of demonstration, surpassed only by the evidence of direct experiment or calculation.

It was by the knowledge of this principle, that the celebrated Dr. William Harvey was enabled to discover the circulation of the blood in man. The Honourable Robert Boyle relates his conversation with Dr. Harvey on this subject, in the following words:-"I remember, that when I asked our famous Harvey, in the only discourse I had with him (which was but a little while before he died), what were the things which induced him to think of a circulation of the blood? he answered me, that when he took notice that the valves in the veins of so many parts of the body were so placed, that they gave free passage to the blood towards the heart, but opposed the passage of the venal blood

the contrary way, he was invited to think that so provident a cause as Nature had not placed so many valves without design: and no design seemed more probable than that, since the blood could not well (because of the interposing valves), be sent by the veins to the limbs, it should be sent through the arteries and return through the veins, whose valves did not oppose its course that way." It is evident from this, and many other similar instances, that, in examining the subjects of Natural History, we shall best advance the science, by considering attentively the uses and ends designed by Nature in their formation, and the functions which their organs are destined to perform. This manner of investigation has been objected to by some philosophers, among whom is Des Cartes, as being a presumptuous attempt on the part of human reason, far above its powers, to penetrate into the secret designs of the Creator. The following passage, extracted from the works of Mr. Boyle above quoted, forms a satisfactory answer to this objection:-"Suppose that a countryman, being on a clear day brought into the garden of some famous mathematician, should see there one of the curious gnomonic instruments, that show at once the place of the sun in the zodiac, his declination from the equator, the day of the month, the length of the day, &c., &c., it would indeed be presumptuous in him, being unacquainted both with the mathematical disciplines, and the several intentions of the artist, to pretend or think himself able to discover all the ends for which so curious and elaborate a piece was framed: but when he sees it furnished with a style, with horary lines and numbers, and, in short, with all the requisites of a sun-dial, and manifestly perceives the shadow to mark from time to time the hour of the day, it would be no more a presumption than an error in him to conclude, that (whatever other uses the instrument was fit or was designed for), it is a sun-dial, and was meant to show the hour of the day." The whole science of Natural History teems with instances, showing the successful application of the general principle called the conditions of existence. Thus, when we see an animal possessed of a capacious stomach, long intestines, and a massive structure, we may safely infer that it is herbivorous, or feeding on vegetables, slow in its movements, and of timid and gentle habits. On the contrary, when we find an animal with short intestines, straight stomach, and armed with weapons of offence, we immediately conclude it to be carnivorous, or feeding upon flesh, and of a fierce and active disposition.

It is further observed by the author, in his Lectures on Comparative Anatomy, that the construction of the alimentary canal determines, in a manner perfectly absolute, the kind of food on which the animal is nourished. For, if the animal did not possess, in its senses and organs of motion, the means of distinguishing the kinds of aliment suited to its nature, it is obvious that it could not exist. An animal, therefore, which can only digest flesh, must, to preserve its species, have the power of discovering its prey, of pursuing, of seizing, of overcoming, and of tearing it in pieces. It is necessary, then, that the animal should have a penetrating eye, a quick smell, a swift motion, address and strength in the jaws and talons. Agreeably to this necessity, a sharp tooth, fitted for cutting flesh, is never co-existent in the same species with a hoof covered with horn, which can only support the animal, but cannot grasp any thing: hence the law, according to which all hoofed animals are herbivorous, and also those still more detailed laws, which are but corollaries to the first, that hoofs indicate molar teeth or grinders with flat crowns, a very long alimentary canal, with a capacious and multiplied stomach.

It is only after having exhausted all the laws of General Physics, and the conditions of existence, that we are compelled to resort to the simple laws of observation. The most effectual mode of deducing these is by comparison; by observing the same body successively in the various positions in which it is placed by Nature; and by comparing different bodies with each other, until we obtain a knowledge of some constant relations between their structure and the phenomena exhibited by them. These various bodies thus form a species of experiments, performed entirely by Na ture's hand, where different parts of each are supplied or abstracted, as we would desire to treat them in our laboratories: and the results of these additions or abstractions are presented to us spontaneously. We are thus enabled to deduce the invariable laws influencing these relations, and to apply them in a manner similar to the laws determined by general physics. Could we but incorporate these laws of observation with the general laws of physics, either directly or by means of the principle called the conditions of existence, the system of natural science would be complete, and the mutual influence of all beings would be perceived throughout the whole. To approach this great end the efforts of naturalists should be steadily directed.

All researches of this kind presuppose that we have the means of distinguishing with certainty, and of describing to others with accuracy, the objects under investigation; otherwise, we shall be continually liable to fall into confusion, amidst the innumerable beings which surround us. Natural History ought, therefore, to have for its basis, what has been technically termed a system of nature, or a methodical

1

and extensive catalogue, arranged with divisions and subdivisions, in which all beings shall bear suitable names and distinct characters.* That we may always be able to discover the character of any particular being from knowing its name, or the name from knowing its specific character, we must found this peculiar description upon some essential or permanent properties of the being. We must not derive the character from habits, or colour alone, as these properties are ever liable to be modified by external circumstances, but from INTERNAL ORGANIZATION OF COMPOSITION.

When Natural History was in its infancy, the objects were few and easily remembered. Systems of classification were either neglected as unnecessary, or confined only to those general divisions and subdivisions, which it was impossible to overlook. But ever since the days of Aristotle, A. C. 330, when Alexander the Great had increased the number of known species of animals by some of the productions of the conquered East, the necessity of a precise system of classification has been universally admitted; and now, the progress of geographical knowledge has enlarged the bounds of the science to so vast an extent, and disclosed a variety so inconceivable of forms hitherto unknown, that the naturalist would, without classification, be overwhelmed with endless details. Yet the different kinds of animals are daily becoming more numerous by the contributions of enlightened travellers. In 1750, the number of distinct species of insects was estimated at 20,000, and now it cannot be less than 100,000. And when it is considered how small a part of the globe has been carefully examined, when there are vast tracts in the interior of Asia, Africa, America, and the isles of the Southern Ocean, which have never been trod by civilized man, while many portions, even of Europe, are but superficially explored, and when the depths of the vast ocean present insuperable barriers to investigation, we may reasonably expect, that the whole number of species will be found to be very much greater. Improved microscopes have disclosed myriads of animalcules previously unknown, and almost every fluid contains an enormous variety of distinct forms, many of them peculiar to each kind of liquid. All this apparent chaos is by the art of the naturalist reduced to a beautiful system, and immediately one universal principle of order may be traced throughout the whole.

Scarcely any object in nature is so peculiar in its formation, as to be at once defined by any single trait in its character. We are almost always under the necessity of combining many of these peculiarities, in order to distinguish an object from others to which it is nearly allied; especially when these allied objects possess some, though not all, of its peculiarities, or when these peculiarities are united to other properties of a different character. The more numerous the objects are which have to be distinguished, the more it becomes necessary to multiply the terms of their several characters; so that, without some contrivance, they would become descriptions of inconvenient length. To remove this objection, divisions and subdivisions are employed. A certain number of allied species are collected together into one group, and it then becomes necessary only to express, for their respective characters, the points wherein they differ, which, according to the above supposition, form but a small part of their description. The whole group is termed a genus. The same difficulty would be experienced in distinguishing the genera from each other, if we did not repeat the operation, by grouping the allied genera to form an order; and then assembling the allied orders to constitute a class. Subdivisions intermediate to these are established when necessary. This aggregation of divisions, in which the superior contain the inferior, is termed a system or method. It may be compared, in some respects, to a dictionary, wherein the properties of things are an index to their names, being the reverse of ordinary dictionaries, in which the names are given, as an index to their meanings or properties.

Thus it appears, that a collection of individuals of the same form

constitute...

Of species...

Of genera..

Of orders......

And of classes...

.a specics,

..a genus,

.....an order, ....a class, .......a kingdom.

To explain this arrangement more clearly, we shall take an example from the Animal Kingdom; suppose, the horse. This animal belongs to the class Mammalia, containing all which suckle their

The word character, in Natural History, denotes that peculiar description of an object which distinguishes it from all others. Thus we say, the character of man is, "Teeth of three kinds, posterior extremities furnished with feet, anterior with hands, &c. &c."-Translator.

young; to the order Pachydermata, or thick-skinned animals, such as the elephant, boar, and rhinoceros; and to the genus Equus, composed of animals with solid hoofs, as the ass and zebra. From these allied species it is finally distinguished by the term caballus. Thus, the scientific name of the horse is Equus caballus, terms derived from its genus and species. But, as different naturalists often give different names to the same animal, it becomes necessary to add to these the name of the naturalist who first introduced the generic and specific names. In the above example, we therefore write Equus caballus, LINN. for the celebrated naturalist Linnæus.

Such is the method indispensably required, in framing the arrangement of the almost unbounded objects of Natural History.

We need scarcely caution our readers against the errors of the Realists, once the cause of so much contention in the schools. The individuals alone, or more properly the particles composing each individual, have a real existence in nature, while species, genera, &c. are but general words, invented by man, to express certain points of resemblance, which he perceives among their properties. There are two different principles observed in the formation of systems of arrangement, according as they are intended to be artificial or natural. The design of an artificial system is to enable the student to find the name of an object, whose properties are known, and to this alone its utility is, in general, confined. Thus, Linnæus arranged plants, chiefly according to the number and situation of the stamens and pistils contained in their flowers. But, being founded on the comparison of only one single organ, the artificial method conveys no general knowledge of other properties, and frequently separates objects which ought never to be disjoined. It is altogether different with a natural method. Its divisions are not founded upon the consideration of a single organ, but are derived from characters presented by all the parts of the object. Accordingly, the objects are disposed in such a manner, that each bears a greater affinity to that which immediately precedes and follows it, than to any other.

When this method, therefore, is good, it is not confined to a mere list of names. If the subdivisions have not been selected arbitrarily, but rest upon real and permanent relations, and upon the essential points of resemblance in objects, the natural method is the means of reducing the properties of beings to general laws, of expressing them with brevity, and of fixing them permanently on the memory. To produce these results, objects must be assiduously compared under the guidance of another general principle, necessarily proceeding from that of the conditions of existence formerly explained, called the subordination of characters, which we shall here briefly elucidate. The several parts of a being having a mutual adaptation, there are certain constitutional arrangements which are incompatible with others; again, there are some with which they are inseparably connected. When, therefore, certain peculiarities belong to an object, we may calculate with facility what can, and what cannot, co-exist with them. We, accordingly, distinguish by the terms important or leading characters, those parts, properties, or constitutional arrangements, having the greatest number of these relations of inconsistency, or of necessary co-existence; or, in other words, which exercise upon the whole being the most marked influence. Others of minor importance are termed subordinate characters. The superiority of characters is sometimes determined in a satisfactory manner, by considering the nature of the organs described in the character. When this is impracticable, we must resort to simple observation; and, from the nature of a character, must infer such to be the most decided as are found the least liable to vary, when traced through a long series of beings, differing in degrees of resemblance. For this reason, we should select for the grand divisions, those characters which are at once important and permanent; and may reserve, with propriety, the subordinate and variable characters for the minor subdivisions of our system.

There can be but one complete system, and that is, the natural method. Here species of the same genus, order, or class, resemble each other more than they do the species of any other corresponding division; the place of each object is decided by its relation to surrounding beings; [and the whole arrangement forms a type of that beauteous system of nature which, "changed thro' all, thro' all remains the same." Even Linnæus, who framed the best artificial system ever presented to the world, observes, in his Philosoph. Bot. § 77, that natural historians should regard the natural method of arrangement as the ultimate aim of their labours. In a word, the natural method is the very soul of Natural History

"Unerring nature, still divinely bright,

One clear, unchanged and universal light."]