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muscular grasp is good, and the fulness of colour when the optical adhesiveness is of a high order. The highest pictorial intellects may probably approach very closely to the facility and fulness of the real presence.

The recovery of past images is one of the commonest efforts of Volition. In this case the effort must direct itself towards the muscles of the eye, and these will imitate or recal the movements entering into the picture. If it is a building the muscles will ideally trace out the form, and give an opportunity to the imbedded luminous impressions to recover themselves. The more easily we can repeat some of the movements of the original view, the more likely we are to draw all the rest in their train, and, with the movements, the lights, shadows, colours, and all the minute imagery that makes up the detail of the building.

SENSATIONS OF DIFFERENT SENSES.

The concurrence of Sensations in one common stream of consciousness,—in the same cerebral highway,-enables those of different senses to be associated as readily as the sensations of the same sense. We will now therefore review the more remarkable instances that arise out of this concurrence, and in so doing it will be convenient to include Movements and their ideas along with Sensations.

29. Movements with Sensations.-Under this title I would cite the association of actions with sensible signs, as in all that department of lingual acquisition wherein names have the meaning of command, direction, guidance, control. Every movement that we make is connected with a certain form of words or a particular signal, for the purpose of setting it on at any time. The child learns to connect vocal sounds with its various actions, and thus becomes amenable to command and direction. This education is continued all through life, and the signs for indicating action may be varied without end. The notes of the bugle, the signals at sea, the directions posted up on the walls, have all this acquired power of commanding movements. The same association enters into the education of

animals; the horse and the dog soon learn to connect specific actions with the language, tones, and looks of human beings. Long before children possess the power of utterance themselves, many of their actions are associated with the sounds of language as uttered by others.

30. Muscular Ideas with Sensations. The enduring forms, impressions, or ideas of movement, are associated with sensations, and the two things are in the habit of recalling each other. In the three higher senses we have seen that there is an association of these two elements; many tactile, audible, and visible sensations being a coalition of the two. There are instances, however, besides these. The most interesting that occurs to me is a case coming under Sight. We come to connect the visible appearances of objects with their weight, hardness, and tenacity,-qualities purely muscular in their perception. Having experience of the weight of a piece of stone of a certain appearance, we associate the appearance with the weight, and the one comes to recal the other; so with hardness or tenacity. In this way we have an associated connexion between substances and their uses founded on these properties. We acquire a strong feeling of the difference between timber and stone, and between stone and metal, so much so that we demand each to be differently applied in all kinds of erections and mechanical operations. It has been remarked that our sense of Architectural proportions is founded on our experience of stone, and would require to be readjusted if iron were as universally employed. If the specific gravity of the rocky materials of the globe had been equal to lead instead of being about two and half times water, our sense of the weight of every piece of stone would have been four times as great as at present, and we should consequently have demanded for the satisfaction of the eye far more massive proportions in every kind of stone-work."

That is, supposing there was no increased tenacity or power to resist crushing at the same time. Iron buildings are less massive than stone, notwithstanding the greater density of the material; but in that case the greater strength of the substance comes into play, and the employment of hollow and slender forms takes off from the weight to be supported.

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31. Sensations with Sensations.-Under this head I might allude to all the combinations that would arise by taking each sense along with every other; organic sensations with tastes and smells, with touches, sounds, and sights; tastes with smells, &c., smells with touches, and so on. But any reader may supply for himself examples of all these cases. I shall merely touch on the associations among the three higher senses.

Touches are associated with Sounds, when the ring of a body suggests how it would feel, as in discriminating stone, wood, glass, pottery, &c. This is a very abundant and generally very secure adhesion. The discrimination and delicacy of the sense of hearing makes it thus a valuable means of knowing what is going on around us.

Touches are associated with Sights in the great comprehensive case of connecting the tactile properties of things with their visible appearance, whereby the one can instantly suggest the other. We associate the tangible qualities of roughness, smoothness, solidity, liquidity, viscidity, with the characteristic impressions they make on the eye, and we can at any time recal the touch by the sight, or the sight by the touch. So we can distinguish metallic, wooden, or rocky surfaces, cloths, leaves, flowers, by both senses; and by association the impression on the one can bring up the other. Every one has a large amount of knowledge existing in the shape of associated touches and sights. We connect likewise the form as revealed to touch with the seen form, and thus make the one confirm the other. Our notion of figure is in fact a coalition of different impressions, and this gives to it a more perfect character than any single impression can convey. I shall speak of this again presently.

Sounds are associated with Sights in innumerable instances. We connect the visible appearances of bodies with the noise they make when struck, as a glass, a spoon, a book, We associate an instrument of music with the peculiar quality of its note; we connect animals with their vocal utterance. So with human beings; every person known to us having a distinctive voice. In acquiring languages we

have to associate the articulate sound with the alphabetical letters.

32. In this case and in all the other cases of heterogeneous association, I am disposed to think that the rapidity of the adhesion will vary with the adhesive quality of each of the two senses entering into the combination. Thus, when sounds are connected with sights, the goodness of the ear and the retentiveness of the eye will both contribute to make the adhesion quick and sure. Whence all associations with sight would come sooner to maturity than the connexions. formed among the inferior sensations. This circumstance it is that puts sight forward as the representative sense. Things that are seen having a more glorious resurrection in the mind than any others, we choose to conceive the objects of nature as they appear to the eye rather than as they affect the ear or the touch. Of all the ways that an orange can strike the senses, the visible aspect is by pre-eminence its revived manifestation, in other words, its idea.'

OF EXTERNAL PERCEPTION. THE MATERIAL WORLD.

33. The perception and knowledge of the material world come through the sensations by their association with one another. The manner of attaining to this knowledge, its exact nature and the degree of certainty attaching to it, give rise to some of the greatest questions of metaphysical philosophy. Two problems especially call for notice at this stage. The first is the origin of the perceptions we owe to vision, namely, the forms and magnitudes of external bodies, and their distances from the eye. Ever since these perceptions were affirmed by Berkeley to be not original but acquired, they have formed an interesting subject of demonstration and discussion with metaphysical writers. The second question relates to the grounds we have for asserting the existence of an external and material world; this question grew out of the other both historically and naturally, and was one of the prominent metaphysical questions of the eighteenth century.

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34 Of the Perception of the Distances and Magnitudes of External Bodies.-In speaking of the sensations of vision we have adverted to the qualities of Colour, Form, and Solid Dimension, of which the eye gives us feelings or impressions. It is to be seen how far these last, together with distance and magnitude, are original and proper to the eye, and how far the result of a fusion of eye sensations with other feelings.

The distinctive impressibility of the eye is for Colour. This is the effect specific to it as a sense. But the feeling of Colour by itself implies no knowledge of any outward object as a cause or a thing wherein the colour inheres. It is simply a mental effect or influence, an emotion or conscious state, which we should be able to distinguish from other conscious states, as for example, a smell or a sound. We should also feel the difference between it and others of the same kind more or less vivid, more or less enduring, more or less expansive or voluminous. So we should distinguish the qualitative differences between one colour and another. Emotional effect, with discrimination in quality, intensity, duration, and volume, would attach to the mere sensation of colour. Knowledge or belief in an external or material coloured body there would be none.

But when we add the active or muscular sensibility of the eye, we obtain new products. The sweep of the eye over the coloured field gives a feeling of a definite amount of action, an exercise of internal power which is something totally different from the passive emotion of light. This action has many various modes, all of the same quality, but all distinctively felt and recognised by us. Thus the movements may be in any direction-horizontal, vertical, or slanting; and every one of these movements is felt as different from every other. In addition to these we have the movements of adjustment of the eye brought on by differences in the remoteness of objects. We have distinctive feelings belonging to these different adjustments, just as we have towards the different movements across the field of view. If the eyes are adjusted first to clear vision for an object six inches from the eye, and