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sentiments. He detested the narrow orthodoxy of the religionists with whom he was most acquainted, but he replaced their superstitious tenets with a more ennobling charity. He could not believe in a deity who was characterized as the fountain of mercy, and who yet predestines his creatures to eternal torment. He was confident that, notwithstanding his errors, he could with trust repose upon

"The bosom of his Father and his God."

These lines express that hopeful trust and confidence

"Where with intention I have erred

No other plea I have

But thou art good; and goodness still
Delighteth to forgive."

His religion was not of a highly spiritual character. As he loved his fellows and could not harbor a malignant thought, he believed that much more the pure and all powerful Deity must look with compassion rather than anger upon the frailties of weak and suffering mortals. He esteemed the God of his worship as he would estimate a good man.

"The heart benevolent and kind

The most resembles God."

Hating hypocrisy and superstition, he yet reverenced the religious observances with which he was familiar, and ever speaks of genuine piety with veneration. His conduct in several situations in life-especially in relation to his marriage-could only have been dictated by conscientious considerations having their origin in religious convictions.

Were there such compensations in the life of Burns that he received a measure of happiness equal to the average of mankind? This question opens a field of inquiry and speculation into which few dare to venture, and fewer still, perhaps, who have answered such questions for themselves would care to give their thoughts to the world. We can only say that we believe the soul to be immortal; that God is just; that this life is but a day in the cycle of eternity, and that death is but an act-drop for the drama of existence which shall continue forever.

ART. IV.-1. Herschel's Treatise on Sound. Encyclopedia Metro

politana.

2. Bartlett's Acoustics. New York.

THE sense of hearing, though of less importance than that of sight, ranks high as a means of acquiring knowledge and avoiding danger. It is by habit that we obtain the power of distinguishing places and things by sound, a capability that belongs no less to the brute than to man. Indeed, some animals seem to rely wholly on their sense of hearing to distinguish the presence of objects. Dr. J. K. Mitchell found the bat to fly as well, and to avoid danger as readily, with its eyes put out, as when it had the use of them; but after having its sense of hearing destroyed it could no longer tell whither it was flying so as to avoid an object or to strike it.

This power, then, which men and animals possess of distinguishing objects by the sound which they make, is no. mean acquisition to beings of locomotion that, in consequence of this ability to move, have many more chances of destruction or injury than such as are confined to one spot. It is a matter of observation that the acuteness of our senses is directly proportional to our wants under certain circumstances, either for the purpose of avoiding danger or acquiring knowledge.

This power of cultivation is not limited to man; the brute possesses it also. Some animals possess by nature senses extraordinarily acute, either on the one hand, for avoiding their enemies, or for pursuing their prey. It is altogether inconceivable to us how the dog can follow his master's track from the scent which he leaves through the sole of his boot. We believe, however, that cultivation will make man's senses nearly as acute as those of any animal. We are acquainted with a little girl who depends on her sense of smell to distinguish the quality of anything. It is said that "Mr. James Gardner, the geographer, can rule blindfolded or in the dark, with the natural angle of a diamond on

hard white metal, fifty-one lines in the fiftieth part of an inch, and cross them at the same distances with an additional line each way to complete the number of squares."* The sight, though generally the most useful, is comparatively limited. The unaided eye could not distinguish the squares which Mr. Gardner was able to make (6,502,500) by the sense of feeling, in a space of an inch square. In the case of the approach of death in the ordinary course of nature, the sense of hearing remains acute long after the eye fails to perceive things.

For the production of sound three things are necessary: a sounding body, an organ of hearing, and a medium by which the sound may be transmitted from the one to the other. The atmosphere is the ordinary but not the only conductor of sound. The various gases, liquids and solids, all conduct sound with greater or less facility. It was discovered by Hauksber that in a vacuum no perceptible sound could be produced. When a bell is suitably arranged for sounding, under the receiver of an air-pump, it is found that the sound becomes less and less audible as the exhaustion goes on, until at length it ceases altogether to be heard.

It is related by M. Saussure and others, that the firing of a pistol on the summit of Mont Blanc made no louder report than the noise of an ordinary Chinese cracker at the base. This diminution of sound at great heights has usually been attributed to the smaller density of the air. It is a known fact that air under greater pressure conveys sound with increased intensity, so that a whisper in a diving-bell, when sunk to a considerable depth, becoms painfully loud.

The above statement of Saussure, however, does not seem to be confirmed. M. Martins made various experiments with a view of determining the intensity of sound in rarified air. He proved that it depends on the density of the air at the place of the primitive disturbances, and not on that of the strata traversed by it, nor on that of the air surrounding the hearer. This was proved in the course of experiments made with two mortars of the

Mudie's Popular Guide to the Study of Nature, pp. 16, 17.

same fount, upon the velocity of sound ascending and descending. One mortar was placed upon the summit of a mountain, and the other below. At an altitude of 2,682 metres it was found that, with the same charge, the sound was much weaker than that produced 1,117 metres lower. On the top of Mont Blanc, in the same situation in which Saussure made the observation before quoted, and where, he said, he could scarcely hear the popping of a bottle of champagne, M. Martins found that he could distinguish the voices of the guides in conversation at the distance of 400 metres, or nearly a quarter of a mile, and the tapping of a pencil upon a metalic surface at the distance of fifteen to twenty paces.

In order to arrive at something more positive in regard to this matter, M. Martins constructed a diapason so arranged as to give 512 vibrations of sound in a second, thus giving a constant and continuous sound. With a sound having always the same intensity in air of equal density, it is evident that the variable distance at which it ceases to be perceptible in mediums of different densities, will afford a proper measure of the variations of this intensity. Owing to the agitations of the atmosphere, however, these experiments become complicated. In 1814 it was ascertained by M. Holdat and De la Roche, that wind, blowing from the origin of a sound, increased the limit of distance to which it may be heard, and wind blowing in the opposite direction diminished it. Both agree that it can be heard, other things being equal, at the greatest possible distance in air at rest, the noise from the wind, under any circumstances, interfering with the perception of sound. This accords with common experience.

Experiments made with the diapason on a desert plain, in a calm day, gave 254 metres as the limit of sound. The same experiment repeated at 11 o'clock at night under nearly the same circumstances, gave 379 metres as the limit of sound. At 8600feet abovethe levelof the sea similar experiments gave 550 metres as the limit of sound; and at the height of 2,800 feet the limit was 337 metres. We thus see that sound was heard at an elevation of little more than a

mile and a half at double the distance of that at the ordinary surface level, and that the universal stillness observed at great heights seems rather to be owing to the absence of soundproducing causes than to the impossibility of its being heard. These experiments, however, do not really contradict the observations of travellers who have been struck with the weakening of sound at great altitudes. "In fact these travellers having ascended suddenly from the plain upon the mountain, their organs, and particularly those of hearing, have not had time to put themselves in equilibrium with the ambient air."

M. Martins did not make his experiments till after several days' sojourn at the elevations cited, and when his organs of hearing had adapted themselves to the rarer medium. The inhabitants of very elevated region of country, especially in tropical America, do not suffer from the effects of a rarified medium, owing to the power of adaptation of the human system, which enables man to live without inconvenience under conditions that could scarcely be endured if he were suddenly introduced into them. "There are causes, however," observes M. Martins, "whieh favor the hearing of sound on high mountains, that more than compensate the rarefaction of the air." Among these causes silence holds the first rank. On the grand plateau of Mont Blanc “there is a repose only broken by the noise of wind or thunder. In calm weather the silence is so profound that sounds are heard at a great distance, although their intensity is much less than in the low country." Other causes exist, such as the nature and configuration of the soil, the hygrometric state of the air, and the absence or presence of " aërial currents."*

The fact that sounds can be heard farther at night than in the daytime early attracted attention. Humbold's attention was called to it by noticing that the noise made by the rush of the cataracts or the Orinoco, in the plain surrounding the Missions of Atures, is three times as loud by night as by day. This is partly owing to the cessation of the noises

*Annual of Ser. Discovery for 1852, pp. 151-2.

+ Travels in Equin. Regions, p. 211.

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