science, or of that artificial comprehension of the world already spoken of as embracing the true links of causation and power. If the fact of repetition does not deeply impress a person, and if, moreover, such person is very much taken up with the more intrinsic appearances and properties of the objects-their colours, forms, textures, &c.-it might be justly concluded that the gift of numbers had been denied in the case. Again, in viewing the essential links of causation, we find that form and lines have very much to do with them. Straight lines, and straight-lined figures, curved lines of a highly symmetrical kind, such as circles, are incessantly present among the conditions of the world's movements and successions; consequently minds that can rigidly conceive this class of forms, and can hold on by them in spite of the allurements of beauty and taste-demanding, as these do, a totally different class of forms and directions-are to a certain extent qualified for the scientific point of view. The contemplation of mathematical lines and figures is rather a painful exercise to the majority of mankind; to a few individuals it is easy and natural. In the next place, the firm and ready conception of unmeaning forms-such as the letters of the alphabet used as mere symbols and marks-is an essential requirement of the scientific intellect. There must be not merely a vivid alphabetical memory, but a vivid recollection of the arbitrary meanings attached to alphabetical and symbolical marks. A person on being told once to associate for the time in his mind the letter a or x with a particular thing, must be able, on the force of that one telling, to hold the two fast together in his mind through a long series of symbolical manipulations and reasonings. The forming instantaneously of firm mental ties among symbols, lines, figures, quantities, and other abstract notions appealing to hardly any parts of our nature except the sense of naked forms, of quantity or plurality, is the faculty that constitutes a scientific endowment of mind. So many of these arbitrary connections have to be made in the course of a single chain of scientific proof or of investigation, that unless they cohere in the intellect without difficulty or delay, such processes are utterly impracticable.

The peculiarities now detailed-the intense mental grasp of quantity, number, mathematical lines and forms, and the power of taking firm hold, at a moment's notice, of symbols and arbitrary meanings are only given as a sample of the elements that go to make the scientific mind and the scientific conception of the world. Many other primary notions of the same class might be pointed out, but none more characteristic than these, or more contrasted with the unscientific impressions derived from nature. The sense of force, pressure, energy, or power, enters largely into philosophical discussions, but under the restraints above specified; that is to say, the forces of nature have to be studied under mathematical conceptions and forms, and in a way very different from the treatment they receive at the hand of the poet. In fact, the philosopher succeeds best by never indulging the feeling of force at all, but by resolving all nature into distances, shapes, and changing situations. We cannot arrive at the secrets of nature's forces by interposing our own feelings of force into the matter: the tendency to explain the world's movements by our own has been one of the permanent sources of error and fallacy.

Each of the primary natural sciences, as arranged at the present day,

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corresponds to a distinct department of natural phenomena and operations: mathematics, physics, chemistry, &c. are all distinguished in this respect. It may happen, therefore, that individual minds may be qualified specially for the study of one express science, as well as generally for the management of scientific notions. A chemist requires skill in manipulation, and a tolerable eye for appearances, as well as the deeper characteristics of the scientific intellect. A naturalist-whose function it is to look at each natural object in the gross, or in all its aggregate of peculiarities, excepting only their poetic aspect-must have an eye for colour and surface as well as form and outline, and a scrutinising turn, so as to dispose him to dwell over an object till every feature of it be stamped in his mind; while the intellectual grasp or cohesiveness must be such as to bind all these varied features quickly and surely into an aggregate picture. Minerals, plants, animals, have all to be seen, studied, and remembered in this manner. The naturalist requires to have a greater number of susceptibilities awake than the mathematician or the man of pure abstractions; and he is not required to be so intensely cognizant of lines, figures, and quantities in their naked existence apart from the other properties of matter. The student of mind requires the special faculty of a discriminative consciousness; the social philosopher should be impressible to the abstractions expressing social relations, or such ideas as government, social union, family, morality, and the like. The geographer should be a naturalist on the large scale; the expanded area of the globe, and of its contained empires and continents, should be easily held out in his mind's eye, and the picture duly filled up with all its details of mountain-ranges, river basins, deserts, cities, and villages. Such a conception involves an amount of human interest that can hardly be included in any of the notions of abstract science.

It will thus be seen how very few of the ordinary appetites and susceptibilities of human nature can be gratified through the views of nature taken by the scientific mind in its endeavours to get at the links of causation, and predict and explain the course of natural events. The satisfaction that may be derived from the mind's cleaving fast to triangles, circles, ellipses, to quadratic equations and atomic theories, may be obtained in a high degree; to this may be added the pleasure of following out an aim, which is an inalienable possession of the human breast: there is the pleasure, moreover, of tracing and explaining the vast workings of nature, and of bringing simplicity out of complexity, and order out of confusion; also the gratification of acquiring truth and certainty, and the power that thence accrues: these are within the reach of the scientific man. But let him beware of seeking the pleasures of poetry and mystic fascination: the moment that these become an object a taint of corruption is introduced a snare is set in the path, and there is no longer any security for real success.

The notion of analysis, or a certain mode of separating the complex products of nature, and the equally complex effects they produce on the human mind, is very much involved in the philosophic treatment of the world. This is another way of stating the great cardinal fact above noticed, that of the many properties belonging to a natural object, it is only a very few that are forces of causation, or instrumental in carrying on the course of nature's changes; and hence it is essential that a separation

should be made between such as have no reference to causation and such as enter into the particular train of movements that we may be considering at the time. Thus of all the effects that a mountain can produce on our minds, and all the properties that we ascribe to it in consequence, very few of these are at all relevant in the question of gravitation: its colours, vegetation, and aspect of sublimity must be put out of the view in this consideration; the minerals and metals that compose it must be looked at in the one sole aspect of bulk and comparative weight; the imposing form must be taken solely as a key to the solid contents and the distribution of the mass. The elements of quantity and naked figure, combined with the consideration of relative weight, are what the mind must entertain in determining the agency of the mountain as a gravitating power-the very same elements that the mind restricts itself to when it looks upon a planet as a circling mass acting and reacting on other planets. This is an example of the analytic process, which is the distinction of science, as combination is the distinction of art, both industrial and poetic. The scientific analysis being in most cases a separation only in idea, it cannot exist in the practical use of substances. If we are to use iron as a weight, we must take all its other properties at the same time; and if there be any of these that are adverse to the object intended, some new substance must be introduced to neutralise them. The necessity of employing very complex objects for the sake of some one of their uses is a never-ending source of difficulty in practical operations, and one of the great trials of practical skill. How to prevent the many actions over and above the one sought from being hurtful is the main consideration in every combination used in art. It is a still greater difficulty in the employment of human beings, from the greater multitude of properties and activities attaching to them.

Analysis is requisite for this other reason-which is but an extension of the foregoing-that although the objects of nature may have various properties concerned in causation, these properties belong to different trains of causes; and as the study of nature imperatively requires that we should confine ourselves to one train of effects at a time, it is necessary that we should separate in our minds the various qualities from one another, for the purpose of ascertaining the causation due to each. The substance gold enters into many different streams of causation: it has weight or gravity, and exerts by this property the effect of mechanical pressure; it has cohesion, by which it resists blows and distension; it has malleability, by which it is susceptible of being spread out into thin leaf; it has a group of chemical powers-such as its resistance to oxidation; it has a special effect upon light, whence it derives its colour and lustre. Now although every one of these properties is concerned in causation, they belong to different kinds of causes, and on every one of them the substance fraternises with a distinct class of objects. Science must arrive at the individual causes operating in nature, and assign the precise efficacy of each; and in handling any one of the complex substances of the globe, it must treat it under one of its attributes at one time, and under another at another time, and thus make it the subject of a great many separate studies and expositions. To this we are driven from no other reason than that it has pleased the Creator to constitute the world on the plan of

having a great many different threads of causation-mechanical, chemical, vital, &c.-embodied in substances in very unequal degrees; so that things brought together as being similar in one effect-transparency, for example -differ in a great many other effects. It is the attribute and the glory of a philosophical mind to adapt itself precisely to what it finds in the world, and to repudiate the idea of dictating the facts or the order of creation.

So much for the sentient attributes of the philosophic mind, or the kind of impressions and properties that it must be intensely susceptible to and retentive of, and which are essentially unlike the impressions and properties retained by the larger sensibility of the artistic mind. We require now to allude to the creations that are called into existence for more completely laying hold of the framework of the universe and for explaining its succession and predicting its future. The creations of the poet are, certain forms of language, whose utterance excites and intoxicates men, and brings them into more perfect unison with the grandeur and poetic influences of the world; and also certain successions of imagery and events having the same peculiar influence on the mind. The other classes of artists work up their materials for the like purpose. The creations of the artisan and the man of business consist in the construction of machinery from the various ingredients of the world, for working out specific effects by a nice adjustment of nature's trains of causation. The creations of the man of science are more purely intellectual than any of these, and consist partly in adaptations of the same machinery of language which is the medium of the poet's influence, and partly of a multitude of diagrams and symbols of his own contriving.

As the peculiar composition of the world demands of the philosophic man a separate attention to things that really cannot exist in separation-an intellectual isolation, where an actual isolation is impossible -some machinery is requisite to effect this isolation; and the machinery differs somewhat according to the subject. To isolate lines and forms, outline diagrams are employed like those in Euclid; the circular, triangular, elliptic forms which cannot exist in nature without the accompaniments of solidity, &c. are represented by skeletons, whose outlines are considered, by courtsey, as having no solidity or thickness, and on these the mind exercises itself in determining the various collaterals and consequences of form apart from all other attributes. Another method of seizing hold of isolated properties, and of pointing them out to other minds, is by verbal definitions, or forms of speech, carefully contrived so as to indicate the thing in question and to exclude all other things. Every one knows what a definition is, and it is therefore needless to occupy our space with examples of this peculiar creation of the scientific mind. Coincident with the use of diagrams and definitions is the employment of general terms, which have reference to some isolated property or distinct influence in the stream of causation, and at the same time bring together a number of individual objects which all possess this power in common; thus the name quadruped' is a general term, having this twofold function of specifying an isolated property and naming a number of individual things, technically denominated a class.' As the isolation of separate properties proceeds in the course of investigation, new general terms are formed, and new classifications introduced. It is, moreover, required of the philosophic man that

he should revise the generalities made by the unphilosophic multitude, and substitute correcter modes of isolating the threads of causation, and correcter classifications of the objects of nature.

We have had occasion to remark that the links of causation of objects are sometimes such as the senses cannot seize at all, and become apparent only by indirect means, which do not tell us where the action lies. This is the nature of the chemical and vital actions, for of these the senses give us the gross results, but furnish no key whatever to the ultimate threads of causation. Gravitation we can comprehend by our senses, but it is not so with the subtile sequences in chemistry and physiology. The links of power in these actions, unfortunately for us, turn upon the atoms or minute particles of bodies, which defy even our microscopic vision; and we are driven to a creative process in order that we may apprehend what goes on, and render a strict account of the actual successions. We transfer from the sphere of sense the notions that best chime in with what takes place beyond the range of sense; and if the notions thus transferred or imagined enable us to render an account of the invisible thread of events, such as to explain all the visible results, we feel satisfied that our assumption is correct. For example, the notion of polarity-gained first from conspicuous objects, as magnetic bars, and terrestrial and celestial globes— is applied to express and represent the invisible atoms of crystallised and other substances, and to render an account of the attractions, repulsions, and other links of causation that hinge on these atoms; and thus, by means of the seen and tangible, we form an image of the unseen, and thereby trace the hand of nature in her most secret recesses. It may easily be supposed that the philosophic profession has found extensive employment in filling up, by imaginary figures and processes, these gaps and blanks of vision, and that this is the most arduous of all the operations of scientific inquiry. The atoms of chemistry can never be seen; the cells of physiology are partly visible by the microscope; but what is actually seen has to be very much enlarged by means of comparisons and notions otherwise derived, when we attempt to assign an exact order of succession and reproduction that will account for all the results. But for the impenetrable veil that hangs over large portions of the chains of nature's causations, we should ere this time have been much farther advanced in our comprehension of the machinery of the world. The stream of natural actions and events, which in some parts of its course is open and apparent, becomes in other parts submerged and withdrawn from human vision; and we are left to the toilsome process of applying analogies and guesses, and creating imaginary courses, taking our hints from an accurate consideration of the visible portions, and verifying our suppositions by their agreement with the seen issues of things. If a being were formed capable of seeing ultimate atoms and cells, and all their quiverings and motions, as easily as we can see the movements in a game of bowls, such a being, by the help of the mathematical skill of the present generation, might shortly reveal to us the deepest secrets of creation; instead of which we must plod on for centuries at the drudging trade of contriving comparisons to suit what we can never see, and trying first one and then another, till, after infinite loss of pains, we fill up the gap of sense by the mere force of scientific reason and imagination.