« PředchozíPokračovat »
In stating the fact of the natural tendency of the human body to float, it must of course be understood with the qualification of its being gently immersed; for the impetus given by the fall of the body into water must occasion its sinking to a depth proportioned to the force of that impetus. Its natural buoyancy, however, soou impels it again to the surface, where, after a few oscillations
and down, it will in time settle with the head free. In the alarm of falling into water, ignorant or timid people, as soon as they again rise to the surface, stretch the arms out to grasp at whatever may present itself, and in so doing effectually keep the head under; as the arms and head, together exceeding in weight one-tenth of the whole body, cannot both remain above the surface at the same time. By struggling thus, the buoyancy of the hollow trunk of the body occasions the more weighty portion of the head and shoulders ultimately to sink under, while the ridge of the back becomes the portion exposed: in this attitude water is swallowed, by which the specific gravity is increased, and the body settles to the bottom, only to rise again from the effects of dissolution.
Infants float in safety if fortunate enough to rise to the surface with the face uppermost; as they are incapable of fear, the buoyancy of the body is left to its natural efficacy, and they will continue on the surface as long as that posture is retained undisturbed. Many instances of this kind have occurred, as well as many similar and extraordinary achievements of grown persons, who bave been known, under the paroxysms of frenzy, to exhibit powers of floating and even of swimming, of which, in their sane moments, they appeared and conceived themselves to be utterly incapable. Persons subject to sleep-walking have in the same manner been known to afford singular instances of nature triumphing over the difficulties which in our waking moments fear suggests. We have the instance of a poor crazy girl, (mentioned by Bernardi,) who had a fancy whenever she observed frogs thrusting their snouts above water—and she exhibited a singular alacrity io making such discoveries—to plunge immediately into the water, however deep, in pursuit of her favourite sport; she generally succeeded in catching her game, and never failed to reach the shore with safety and ease, exulting in her address.
Few of the lower animals are rendered incapable of swimming by fear, though many of them exhibit great reluctance to venture into the water. When a dog has for the first time been plunged into deep water, and sinks, he no sooner regains the surface, than he deliberately looks around to judge of the best course, and then makes with speed for the shore. Though man and animals of this class seem alike capable of floating, the latter possess the supe
riority in the water of retaining their natural position; so that while their length of neck enables the head to be elevated, the legs remain naturally in the best disposition for effectual
progress in the water the same as on land. The respiratory organs of man, on the contrary, are less conveniently placed for being protruded upwards; while an entirely different motion in swimming is required from what is usual to his limbs. Moreover, animals have this additional advantage, that the peculiar formation of their bodies occasions their rising to the surface with the head up and free, and remaiuing afloat in that position; while the centre of gravity in man is so placed, as to give the body a tendency to a prostrate position, which it demands well-directed efforts to counteract: for the capacity to preserve life is not furnished absolutely by nature, but requires, to a certain extent, the assistance of reason or art; accident, ignorance, fear, or whatever else paralyzes this co-operation, renders the gift of nature of no avail. The ape, a creature so nearly resembling the human forn, affords a curious elucidation of this fact. He possesses exactly the same adaptation for floating that man does, but is unable to swim because he is incapable of managing so as to keep his head above water. With the ape reason is absent, while fear is present, so that destruction must be inevitable. Man, on the contrary, can discover where the difficulty lies, and by management and practice is enabled to overcome it.
The principal reasons given by Bernardi for recommending the upright position in swimming in preference to the horizontal, as commonly practised, are--its conformity to the accustomed movement of the limbs; the freedom it gives to the hands and arms, by which any impediment may be removed, or any offered aid readily laid hold of; vision all around; and a much greater facility of breathing; and lastly, that much less of the body is exposed to the risk of being caught hold of by persons struggling in the water, a circumstance so often fatal to those who adventure to the assistance of others.* A person swimming in an upright posture advances more slowly, but he can continue his course infinitely longer. There can be nothing more beneficial to a swimmer than whatever tends to husband his strength, and to enable him to remain long in the water with safety. A learner is taught, by the general practice, to conclude, that his existence in the water depends entirely upon the unceasing efforts of his arms and legs, and is seldom placed in deep water until he has laboriously
* In cases where endeavours are niade to save persons in danger of drowning, they should be laid hold of by the hair, and, if possible, got on their backs, in which position little effort is required to support the bead above the surface, provided suchr . persons have presence of mind enough to retain their arms under water, and so suffer themselves to be tranquilly pulled along.
achieved some power of swimming in shallow; hence the apprehension of remaining at the mercy of his own efforts, renders contidence of such difficult acquisition as materially to retard and enervate even proficients in the art.
In teaching, Bernardi proceeds upon a plan considerably different from the usual one; his primary object is to enable the pupil to float in an upright posture, and to feel a decided confidence in the buoyancy of his body. He proceeds at first with as great caution and deliberation as a nurse teaching a child to walk, supporting the pupil under the shoulder until he floats tranquilly with the head and part of the neck above the surface, the arms being stretched out horizontally under water; from time to time the supporting arm is removed, but again restored so as never to suffer the head to sink, which would disturb the growing confidence, and give rise to efforts destructive to the success of the lesson. In this early stage the unsteadiness of the body is the chief difficulty to be overcome: against this we are disposed, from our habits on land, to trust to the resisting fulcrum of the heel, which cannot, in a yielding medium, prove of any avail. Instead of the heel, it is the head which, like the rudder of a ship, is the great regulator of our movements in water. The smallest inclination of the head and neck to either side instantly operates on the whole body, and, if not corrected, will throw the body into an horizontal posture. The pupil has therefore to be taught how to restore any disturbance of the just equilibrium, by a cautious movement of the head alone in an opposite direction. This first lesson being familiarized by practice, he is then taught the use of the legs for balancing the body in the water : the one of these being stretched forward and the other behind, and the arms laterally, he will soon find himself steadily sustained, and independent of further aid in floating. Fat people, being naturally more erect, find less difficulty in acquiring this upright position with steadiness, than thin persons; and none experience so much as those who have acquired the habit of stooping.
When these first steps have been gained, the sweeping semicircular motion of the arms is shown; this is practised slowly without motion forwards until attained with precision; after wbich a slight inclination of the body from the upright position occasions its advancing. The motion of striking with the legs is added in the same measured manner, so that the pupil is not perplexed by the acquisition of more than one lesson at a time.
A person who has learnt to sustain his body afloat in an upright posture may at any time rest almost without motion, or he» may move gently forward at pleasure. The strength may likewise be recruited by using the arms and legs alternately, turning
first the right shoulder and then the left to the water; for by this means less resistance is opposed, than by presenting the whole breadth of the breast. The upright position a little inclined backwards, (which, like every other change of posture, must be done deliberately, by the corresponding movement of the head,) reversing in this case the motion of the arins, and striking the flat of the foot down and a little forward, gives the inotion backward, which is performed with greater ease than when the body is laid horizontally on the back. The same motions either backward or forward may be accomplished in a sitting position; and neither of these ought to be considered too fanciful for practice: from the yielding nature of the element, a frequent change of attitude becomes agreeable, and the greater the number of postures to which the body can be familiarized, the better-as the resources for repose are so much the more augmented. There is a mode of treading deliberately in the water, by which a person, with the head and shoulders above the surface, appears to walk the same as on dry land; and in fact as soon as familiarity bas established the sufficient adjustment and balance of the body, as well as the power of guiding the movements by the position of the head and neck, it becomes as easy to vary the postures in water as on shore. So equally does the element surrounding every portion of the body support its different parts, that we lose in a manner the consciousness of weight, and with it that instinctive impulse to prevent sinking, which creates a constant counteraction in some of the sets of muscles with which our bodies are furnished. It is perhaps to the cessation of these involuntary efforts, which however imperceptible must notwithstanding occasion fatigue, and are never entirely suspended except in sleep, that we owe some of the restorative qualities of that blessed state of repose. Akin to which, therefore, are in some respects the positions of rest in the water, which when fully attained are such, that one may with confidence stretch out the wearied limbs in utter inaction, until again refreshed and invigorated for renewed esertion.
There are besides other positions for swimming: by alternating first the one shoulder forward and then the other, speed is much accelerated; this screwing movement divides the water advantageously, and forcibly propels the body; but it is attended with considerable fatigue on account of the whole body being thus brought into simultaneous motion, and therefore is a practice which ought in general to be reserved for any emergency of urging our way through difficult water.
Swimming on the back, although at first somewhat difficult, soon becomes easy, and is in every respect a most important at
tainment; being attended with little fatigue, and in practice so safe, that it ought ever to be resorted to upon the occurrence of any difficulty. A swimmer seized with cramp should immediately turn on his back; and by continuing for a little to jerk out the affected limb in the air, taking care however not to elevate it so high as to disturb the equilibrium of the body stretched flat on the surface, he will soon find its natural powers restored. To advance in this position, he must push with the flat of the feet, without regarding an occasional dip of the head under water. He must not attempt to prevent this by dropping down a leg, as a person is instinctively disposed to do; which so far from producing the desired effect will infallibly occasion the body to sink. The limbs must on the contrary always be kept stretched to their full extent, and then there is no danger to be apprehended. The arms may likewise be used in swimming on the back, in which case they act like oars, while the legs are either laid across each other or used to assist.
At every stroke a swiinmer ought to be able to urge himself forward a distance equal to the length of his body. Instead of advancing head foremost, the motions may be reversed so as to go feet first, and although the progress made in this method is but slow, it may for particular situations become advantageous.
The resistance offered by the surface of water when violently struck by a flat object is little inferior to that of a solid body, as any one may experience who strikes it strongly with the palm of the hand, or with a flat piece of wood; in the latter case the resistance often proves sufficient to break the wood. In springing from a height into the water, therefore, great precaution is required, not only that the depth of water shall be sufficient to prevent the possibility of striking the bottom or a rock, but so to dispose the. body as to avoid any awkward concussion from the water itself. In order to cleave the water therefore without injury to the body, the limbs must be kept firm together—the head protected by the bands clasped over it, so as to present a sharp edge, entering the water like an arrow—the feet last and kept close. By taking a diagonal direction in the spring, the risk is considerably diminished, as the resistance is more progressively overcome, and the hands and feet are in a better position for giving assistance. The eyes ought always to be kept open under water, as there is no danger in doing so, and by use, we acquire the complete power of discerning every thing around, and so of avoiding rocks or other interruptions.
For the purpose of diving, we possess to a certain extent the power of contracting the bulk of the body, by drawing it together while the weight remains unaltered. There is no power which is more remarkably augmented by habit and perseverance, than