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seem, like themselves, at an indefinite and equal distance, and therefore contribute to give the whole sky the appearance of the inside of a sphere. Moreover, the horizon seems to the eye to be further off than the zenith; because between us and the former there lie many things, as fields, hills, and waters, which we know to occupy a great space; whereas between us and the zenith there are no considerable things of known dimensions. And, therefore, the heavens appear like the segment of a sphere, and less than a hemisphere, in the centre of which we seem to stand.—And the wider our prospect is, the greater will the sphere appear to be, and the less the segment.

0 45. Of objects seen on the ocean, &c. A vessel seen at sea by a person who is not accustomed to the ocean, appears much nearer than it actually is; and on the same principles as already illustrated. In his previous observations of the objects at a distance, he has commonly noticed a number of intermediate objects, interposed between the distant body and himself. It is probably the absence of such objects that chiefly causes the deception under which he labours in the present instance.

In connexion with what has been said, we are led to make this further remark, that a change in the purity of the air will perplex in some measure those ideas of distance which we receive from sight. Bishop Berkeley remarks, while travelling in Italy and Sicily, he noticed that cities and palaces seen at a great distance appeared nearer to him by several miles than they actually were. The cause of this he very correctly supposed to be the purity of the Italian and Sicilian air, which gave to objects at a distance a degree of brightness and distinctness which, in the less clear and pure atmosphere of his native country, could be observed only in those towns and separate edifices which were near. At home he had learned to estimate the distances of objects by their appearance; but his conclusions failed him when they came to be applied to objects in countries where the air was so much clearer.—And the same thing has been noticed by other travellers, who have been placed in the like circumstances.

CHAPTER VII.

HABITS OF SENSATION AND PERCEPTION. 7.

$ 46, General view of the law of habit and of its applications. There is an important law of the mental constitution known as the law of Habit, which may be described in general terms as follows: That the mental action acquires facility and strength from repetition or practice. The fact that the facility and the increase of strength, implied in HABIT, is owing to mere repetition, or what is more frequently termed practice, we learn, as we do other facts and principles in relation to the mind, from the observation of men around us, and from our own personal experience. And as it has hitherto been found impracticable to resolve it into any general fact or principle more elementary, it may justly be regarded as something ultimate and essential in our nature.

The term Habit, by the use of language, indicates the facility and strength acquired in the way which has been mentioned, including both the result and the manner of it. As the law of habit has reference to the whole mind of man, the application of the term which expresses it is, of course, very extensive. We apply it to the dexterity of workmen in the different manual arts, to the rapidity of the accountant, to the coup d'æil or eye-glance of the military engineer, to the tact and fluency of the extemporaneous speaker, and in other like instances.-We apply it also in cases where the mere exercise of emotion and desire is concerned ; to the avaricious man's love of wealth, the ambitious man's passion for distinction, the wakeful suspicions of the jealous, and the confirmed and substantial benevolence of the philanthropist. Ø 47. The law of habit applicable to the mind as well as the body.

It is remarkable, that the law under consideration holds good in respect to the body as well as the mind. In the mechanical arts, and in all cases where there is a corporeal as well as mental effort, the effect of practice will be found to extend to both. Not only the acts of the mind are quickened and strengthened, but all those muscles which are at such times employed, become stronger and more obedient to the will. Indeed, the submission of the muscular effort to the volition is oftentimes rendered so prompt by habit, that we are unable distinctly to recollect any exercise of volition previous to the active or muscular exertion. It is habit which is the basis of those characteristic peculiarities that distinguish one man's handwriting from another's; it is habit which causes that peculiarity of attitude and motion so easily discoverable in most persons, termed their gait; it is habit also which has impressed on the muscles, immediately connected with the organs of speech, that fixed and precise form of action, which, in different individuals, gives rise, in part at least, to characteristics of voice. The habit, in the cases just mentioned, is both bodily and mental, and has become so strong, that it is hardly possible to counteract it for any length of time.—The great law of Habit is applicable to all the leading divisions of our mental nature, the Intellect, the Sensibilities, and the Will; and as we advance from one view of the mind to another, we shall have repeated occasion to notice its influence. In the remainder of this chapter we shall limit our-remarks to Habit, considered in connexion with the Sensations and Perceptions.

$ 48. Of habit in relation to the smell. We shall consider the application of the principle of Habit to the senses in the same order which has already been observed. In the first place, there are habits of Smell.-This sense, like the others, is susceptible of cultivation. As there are some persons whose power of distinguishing the difference of two or more colours is feeble; so there are some who are doubtful and perplexed in like manner in the discrimination of odours. And as the inability may be overcome in some measure in the former case, so it may be in the latter. The fact that the powers of which the smell is capable are not more frequently brought out and quickened, is owing to the

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circumstance that it is not ordinarily needed. times happens, however, that men are compelled to make an uncommon use of it, when, by a defect in the other senses, they are left without the ordinary helps to knowledge. It is then we see the effects of the law of Habit. It is stated in Mr. Stewart's account of James Mitchell, who was deaf, sightless, and speechless, and, of course, strongly induced by his unfortunate situation to make much use of the sense we are considering, that his smell would immediately and invariably inform him of the presence of a stranger, and direct to the place where he might be; and it is repeatedly asserted, that this sense had become in him extremely acute.—“ It is related,” says Dr. Abercrombie,“ of the late Dr. Moyse, the wellknown blind philosopher, that he could distinguish a black dress on his friends by its smell.”

In an interesting account of a deaf, dumb, and blind girl in the Hartford Asylum, recently published, statements are made on this subject of a similar purport.“ It has been observed," says the writer, "of persons who are deprived of a particular sense, that additional quickness or vigour seems to be bestowed on those which remain. Thus blind persons are often distinguished by peculiar exquisiteness of touch; and the deaf and dumb, who gain all their knowledge through the eye, concentrate, as it were, their whole souls in that channel of observation. With her whose eye, ear, and tongue are alike dead, the capabilities both of touch and smell are exceedingly heightened. Especially the latter seems almost to have acquired the properties of a new sense, and to transcend the sagacity even of a spaniel.”—Such is the influence of habit on the intimations of the sense under consideration.

49. Of habit in relation to the taste. The same law is applicable to the Taste. We see the results of the frequent exercise of this sense in the quickness which the dealer in wines discovers in distinguishirg the flavour of one wine from that of another. So marked are the results in cases of this kind, that one is almost disposed to credit the story which Cervantes relates of two persons, who were requested to pass their judgment upon a hogshead which was supposed to be very old and excellent. One of them tasted the wine, and pronounced it to be very good, with the exception of a slight taste of leather which he perceived in it. The other, after mature reflection and examination, pronounced the same favourable verdict, with the exception of a taste of iron, which he could easily distinguish. On emptying the hogshead, there was found at the bottom an old key with a leathern thong tied to it.

Another practical view of this subject, however, presents itself here. The sensations which we experience in this and other like cases, not only acquire by repetition greater niceness and discrimination, but increased strength; (and perhaps the increased strength is in all instances the foundation of the greater power of discrimination.) On this topic we have a wide and melancholy source of illustration. The bibber of wine and the drinks er of ardent spirits readily acknowledge, that the sensation was at first only moderately pleasing, and perhaps in the very slightest degree. Every time they carried the intoxicating potion to their lips, the sensation grew more pleasing, and the desire for it waxed stronger. Perhaps they were not aware that this process was going on in virtue of a great law of humanity; but they do not pretend to deny the fact. They might, indeed, have suspected at an early period that chains were gathering around them, whatever might be the cause; but what objection had they to be bound with links of flowers; delightful while they lasted, and easily broken when necessary! But here was the mistake. Link was added to link; chain was woven with chain, till he who boasted of his strength was at last made sensible of his weakness, and found himself a prisoner, a captive, a deformed, altered, and degraded slave.

There is a threefold operation. The sensation of taste acquires an enhanced degree of pleasantness; the feeling of uneasiness is increased in a corresponding measure when the sensation is not indulged by drinking; and the desire, which is necessarily attendant on the uneasy feeling, becomes in like manner more and more imperative.

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