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sensation resulting is one of a most disagreeable kind. It would seem to result rather from the jar given to the nervous system than from any influence flowing out of the muscle. The whole frame is agitated with a most revulsive shock, the cold perspiration is felt all over, and a sickening feeling seizes the brain. The breaking down of any prop that we are resting on, the snapping of a rope, or the sinking of a foundation, exemplify the most intense form of the effect. We may probably look upon the peculiar influence whose repetition induces sea-sickness, as of the same nature. The sinking of the ship has exactly the same unhinging action in a milder degree, although when continued for a length of time, this produces a far worse disturbance than any single break-down, however sudden. The precise physiological action in this situation, does not seem agreed upon; the feeling is known to be one of the most distressing that human nature is subject to, being an intense and exaggerated form of stomachic sickness.*

19. We must next advert to what are called passive (but more properly compelled) movements. Riding in a vehicle is the commonest instance. One of the pleasures of human life is to be driven along at a moderate speed, in an easy carriage. Now, it may be supposed at first sight, that there ought to be no feeling of muscular exertion whatsoever in this case, seeing that the individual is moved by other force than his or her own. Under certain circumstances this would be strictly true. We have no feeling of our being moved round with the earth's rotation, or through space by the movement about the sun. So in a ship, we often lose all sense of being driven or carried along, and feel pretty much as if there were

Sea-sickness is explained by some as the result of the excessive flow of blood to and from the head. When the ship makes a downward motion, the feeling of loss of support is accompanied by a rapid flow of blood to the brain, and, when the ship rises, as rapid a flow ensues in the opposite direction. It is asserted further, that the flow either way may be diminished, if an upward motion of the body be made at the time of the ship's downward motion, and a downward motion at the time of the ship's rising; and that sickness can in this way be prevented.

no forward movement at all. The sensibility arising in a carriage movement, is in part imbibed through the eye, which is regaled by the shifting scene, and partly through the irregularities of the movement, which demand a very gentle action of the muscles of the body in order to adapt it to those irregularities. By springs and cushions, all violence of shock is done away, while the easy exercise caused by the commencement and stoppages of the motion, by the slight risings and fallings of the road, is somewhat of the nature of that influence already described as arising from slow and gentle movements. Moreover, as has been observed by Dr. Arnott, the effect of the shaking is to quicken the circulation of the blood.

In horse exercise, there is a large amount of the ingredient of activity. The rider is saved a part of the exhaustion caused in walking, and has yet exercise enough for the stimulus of the bodily functions, and for muscular pleasures.

The rocking chair, introduced by the Americans, who seem specially attentive to the luxuries of muscular sensibility, is another mode of gaining pleasure from movement. Anciently, furniture was adapted for the pleasures of repose solely, but now the boy's rocking horse has its representative among the appurtenances of grown men.

On the whole, it is apparent that a large fraction of physical enjoyment flows out of the moving apparatus and muscular tissue of the body. By ingeniously varying the modes of it, this enjoyment is increased still farther. The pleasure comes incidentally to manual labour, when moderate in amount and alternated with due sustenance and repose, and is a great element of field sports and active diversions of every kind; it is a part of the pleasures of locomotion ; and contributes the principal ingredient in gymnastic exercises and athletic displays.

II. Of the Perceptions grounded in the Muscular Feelings. 20. In alluding to the strictly Intellectual properties of the feeling of expended muscular energy, we had to advert to

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that mode, neutral as regards pleasure and pain, whereby we are occupied with the properties of the object world, as resistance, force, &c.

This function of our muscular sensibility arises, in the first instance, from our being conscious of the different degrees of it. We have not only a certain feeling when we put forth muscular power, but we have a change of feeling when we raise or lower the amount of the power. If we hold a weight of four pounds in the hand, the consciousness is changed when another pound is added. This change of feeling is completely expressed by the word, Discrimination, and is the basis of our intelligence; as pleasure or pain, it is nothing, but as the commencement of knowledge, it is all-important.

The modes of muscular action that affect us by their differences of degree, appear to be three. The first is the amount of exertion, or of expended force, which measures the resistance to be encountered. This is the fundamental experience. The second respects the continuance of the exertion, and applies both to dead strain and to movement. The third is a mode of movement solely; it is the rapidity of the muscle's contraction, which corresponds with the velocity of movement in the organ. In distinguishing the qualities of external things, and in attaining permanent notions of the world, all these discriminations are brought into play.

21. First, with respect to degrees of Exertion or of Expended force. This is the sense of Resistance, the basis of our conception of Body, and our measure of Force, Inertia, Momentum, or the Mechanical property of matter.

Every feeling involves a consciousness of degree or amount to be affected more or less in different circumstances is a consequence of being affected at all. Even when experiencing the pleasure of healthy exercise, or the pain of fatigue, we are aware of differences in the various stages of the feeling. Such differences make one part of the fact that we call knowledge (agreements being the other part).

We have a

To apply this to the case now before us. certain feeling when called to exert our muscular energy in

causing movement, or in encountering resistance. We have a certain degree of consciousness for some one degree of exertion; when the exertion increases, so does the consciousness. If a porter places on his back a load of one hundredweight, he has a peculiar and distinct muscular feeling associated with it; if thirty pounds were added, he would have a sense of the addition in the increased expenditure of force; if thirty pounds were removed, he would have a feeling of diminished expenditure. In short, there is a perfect discrimination of degrees and difference of muscular energy, which serves us as a means of discriminating the resistances that we encounter. Hence we are able to say that one body resists more than another-possesses in greater degree the quality that, according to circumstances, we call force, momentum, inertia, weight, or power. When we encounter two forces in succession, as in a wrestling match or a dead push, we distinguish the greater from the less.

22. Among the various occasions where the sense of graduated resistance comes into play, mention may be made, first, of the momentum or force of moving bodies. Where we have to check or resist something in motion, as in bringing a vehicle to rest, our sensibility to expended exertion leaves with us an impression corresponding to the momentum of the vehicle. If we were immediately after to repeat the act with another vehicle heavier or swifter than the first, we should have a sense of increased effort, which would mark our estimate of the difference of the two forces. Supposing the impressions thus made to be gifted with a certain kind of permanence, so that they could be revived at an after time, to be compared with some new case of checking a moving body, we should be able to say which of the three was greatest and which least, and we should thus have a scale of sensibilities corresponding to the three different degrees of moving force.

Such exercises as digging the ground, rowing a boat, or dragging a heavy vehicle, do not essentially depart from the case of the dead strain; and in all these instances, there is an estimate of expended force. Every carriage horse knows the

difference of draught between one carriage and another, between rough and smooth ground, and between up hill and down hill. This difference the animal comes to associate with the carriage, or with the sight of the road, and in consequence manifests preferences whenever there is an opportunity; choosing a level instead of a rising road, or the smooth side in preference to the rough.

The appreciation of weight comes under the dead strain. We remark a difference between half an ounce and an ounce, or between five pounds and six pounds, when we try first the one weight and then the other. The generality of people can appreciate far nicer differences than these. A sensitive hand would feel a small fraction of an ounce added to a pound. In this respect, there would appear to be wide constitutional differences, and also differences resulting from practice, among different individuals. We are all sensitive to some extent, but there is for each person a degree of minuteness of addition or subtraction that ceases to be felt; this is the limit of sensibility, or the measure of delicacy in the individual case.

There are two modes of estimating weight, the relative and the so-called absolute. By relative weights we understand two or more present weights compared together; as when among a heap of stones we pick out what we deem the heaviest. Absolute weight implies a permanent standard, and a permanent impression of that standard. When I lift a weight and pronounce it to be seven pounds, I make a comparison between the present feeling and the impression acquired by handling the standard weight of seven pounds, or things known to be equivalent thereto. This absolute comparison, therefore, implies the enduring and recoverable sensibility to impressions of resistance, which is also a fact of the human constitution. We can acquire a permanent sense of any one given weight or degree of resistance, so as to be able at all times to compare it with whatever weight may be presented. A receiver of posted letters contracts an engrained sensibility to half an ounce, and can say of any