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River, lake, or sea bathing, (as it will usually be one or other,) is termed in medical language the cool bath, which, "besides cleansing the skin from impurities, is especially fitted to recruit the body during the heats of summer; hence the poet has justly denominated it, The kind refresher of the summer heats.'

The languor they occasion, the excessive perspiration, feeling of relaxation, and inaptitude to muscular exertion, are all relieved, or dissipated, by the cool bath, which likewise restores the appetite. To produce these effects it ought to be taken frequently, not to be continued till a second shivering follows that occasioned by the first immersion, and the bather should observe a state of repose after he has dressed, to prevent the occurrence of the phenomena of reaction. It likewise renders the skin less impressionable, and hardens it against atmospherical vicissitudes. It is proper for all persons to whom the temperature of the water produces no disagreeable sensation, and who experience oppression from heat. Young people and adults take it with advantage. On the contrary, infants, those enfeebled by the advances of age, those in whom the chest is irritable, and those liable to rheumatic pains, should avoid it, and make use of the warm bath instead. It ought never to be taken during the active stage of a secretion, such as perspiration. The exercise of swimming is taken in this bath, and operates beneficially, from the small loss to the economy occasioned by the density of the medium in which the swimmer is immersed, and the sedative, or assuaging influences of the water on the nervous system."

We don't consider our supplementary observations complete without a remark or two on the swimming part of the business, and its mode of effecting the objective exercise of the muscular system; and we wind

up our prolonged quotations from the valuable work of Davis:

"Natation, or swimming, is an exercise that solicits the efforts of nearly the whole muscular system, in one or other of its modes of execution. The alternate abduction and extension, and adduction and flexion, of the arms and lower limbs, call forth all the muscles of these parts to vigorous contraction. The muscles of the posterior or anterior part of the neck, also, are solicited to active contractility, to raise the head above the surface, as the swimmer exercises on the belly or back. And, again, those of the chest are kept in full play to accomplish a large respiration, to keep its cavity well distended in order to maintain the buoyancy of this portion of the body, and to give a fixedness to its sides, that the muscles arising from them, and proceeding to the arms, may have greater power in the motion of these limbs. Perhaps there is no more beautiful exemplification of the influence of the muscular sense,' especially to those who can recollect the precise feelings they experienced on first attaining the art of swimming, than the singular sensation that, in some cases at least, suddenly pervades the frame when the power of adjusting the efforts and movements, so as to preserve the body nicely balanced near the surface of the water, is acquired. Every limb thrills with this delightful feeling, and the element is in a moment subjugated to muscular control. Swimming is an essential portion of the education of the muscular sense, and in man seems to require to be learnt before it can be attained.

"It is an exercise only suited to certain constitutions, and it is in general those endowed with considerable energy that can be benefitted by it: yet in proper subjects there is no exercise more truly invigorating. Ardent youth;

'The same Roman arm,

That rose victorious o'er the conquered earth, First learned, while tender, to subdue the wave ; the sanguine, and those of nervous and irritable temperament, in whom there seems to be an accumulation of excitability, obtain great advantages from it by the derivation of the forces it operates towards the muscular system. There is one consequence of the exercise that renders it very prejudicial in some constitutions, especially those of the feeble and relaxed class,—that is, the increased perspiration which always follows immersion; this is so considerable in them as to render bathing their surest debilitant.

"The heats of summer, as they offer the most alluring invitation to the exercise of swimming, present at the same time the truest index to its beneficial employment. There are certain precautions attached to the practice of the art, the principal of which consist in stopping the ears with cotton wool, dipped in oil; in varying the actions of the limbs to prevent cramps, generally the consequence of fatigue; and in avoiding the water during perspiration, and, as in almost every other active exercise, during digestion." (P. 398.)

Scenic Effects.- After perusing the following remarks, even a common observer of a landscape stretched out before him will attain to something more like the pleasure with which an artist contemplates the beautiful portraiture of light and shade:

"The student of painting soon learns that the lines called outlines, by which he first sketches subjects, do not exist at all in nature, and have to be again effaced in his finished work: for they only mark the place where lights and shades happen to meet. Much may be con veyed to the mind, however, by a mere outline, and particularly if lines of different breadth or thickness are

used to mark the situation of the lighter and deeper shadows.

"The subject of chiaro-oscuro is not so simple as, from the fact of the sun being the great source of light, might at first be supposed; for although this be true, still every body which reflects the sun's light becomes a new source to those about it, and the shading of a picture must have reference to all such sources, and to the colours of the body itself, and of the neighbouring bodies.

"In looking at an extended landscape, it is seen that the near objects considered as wholes are comparatively bright, that their shadows are strongly marked, and that their peculiar colours are everywhere easily distinguishable-as of flowers, fruit, foliage, &c., but farther off the colours become dim, the lights and shadows melt into each other or are confused, and the illumination altogether becomes so faint that the eye at last sees only an extent of distant blue mountain or plain-appearing blueish because the transparent air through which the light must pass has a blue tinge, and because the quantity of light arriving through the great extent of air is insufficient to exhibit the detail. The ridge called Blue Mountains in Australia, and another of the same name in America, and many others elsewhere, are not really blue, for they possess all the diversity of scenery which the finest climates can give; but to the discoverer's eye, bent on them from a distance, they all at first appeared blue, and they have ever since retained the name.

canvas

"In a picture by an artist, who on his stretched on a frame disposes the lights, shades, and colours in the very situations and with the intensities which, on coming from the landscape to the eyes through a plate of glass filling up the frame, they would have had, all that we have now been saying is strictly exemplified. In the foreground the objects are large and

bright, but as the scene is supposed to be gradually more remote, the size and brightness of the objects correspondingly diminish, until at last there is only a dim mixture of blueish or greyish masses forming the horizon and sky."-Dr. Arnott's Elements of Physic, Vol. II. Part I. p. 265. Longman, Rees, & Co., London. 1829.

Electricity: Shock Direct and Indirect.-In order to certify the reader as to the double source of danger in a thunder-storm, which is, in fact, an electric discharge between clouds oppositely electrified, accompanied with the usual phenomena of flash and sound, only operated on a grand and terrific scale,-we shall premise that all bodies are possessed of electricity, and that the spark and noise are not the solitary indications of a disturbance of that fluid in a body, or of its restoration to its equilibrium again. The shock felt by any body, animate or inanimate, when its electrical condition has been disturbed and recomposed, is generally considered to be the direct effect of restoring the balance between positive (vitreous of French philosophers) and negative (resinous of French) electric states: but it may be also caused in a manner indirect and circuitously, in technical words by induction.

In order to show how this occurs, we shall translate a passage from a first-rate work on physic, embracing electricity, in French, by M. Pouillet, wherein the author details an experiment quite conclusive on the point, and which illustrates the principles by a practical example, and can be repeated by any one who chooses so to do at their leisure.

M. Pouillet, speaking of bodies electrified by induction, returning to their original state as soon as the influence ceases, remarks that this may occur in two ways, instan

* Elements de Physique et de Meteorologie. 3rd Edit. Vol. I. Paris: Bechet. 1837. (P. 401.)

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