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more readily, because their violent exertions had wearied them, youthful though they were.

My poor Sylvia's rose ! ejaculated Dr. Heidegger, holding it in the light of the sunset clouds : it appears to be fading again.'

And so it was. Even while the party were looking at it, the flower continued to shrivel up, till it became as dry and fragile as when the doctor had first thrown it into the vase. He shook off the few drops of moisture which clung to its petals.

• I love it as well thus, as in its dewy freshness,' observed he, pressing the withered rose to his withered lips. While he spoke, the butterfly fluttered down from the doctor's snowy head, and fell upon the floor.

His guests shivered again. A strange chillness, whether of the body or spirit they could not tell, was creeping gradually over them all. They gazed at one another, and fancied that each fleeting moment snatched away a charm, and left a deepening furrow where none had been before. Was it an illusion ? Had the changes of a life-time been crowded into so brief a space, and were they now four aged people, sitting with their old friend, Dr. Heidegger ? *Are we grown old again, so soon !' cried they, dolefully.

In truth, they had. The Water of Youth possessed merely a virtue as transient as that of wine. The delirium which it created had effervesced away. Yes! they were old again. With a shuddering impulse, that showed her a woman still, the widow clasped her skinny hands before her face, and wished that the coffin-lid were over it, since it could be no longer beautiful.

Yes, friends, ye are old again,' said Dr. Heidegger; "and lo! the Water of Youth is all lavished on the ground. Well - I bemoan it not; for if the fountain gushed at my very door-step, I would not stoop to bathe my lips in it — no, though its delirium were for years instead of moments. Such is the lesson ye have taught me!'

But the doctor's four friends had taught no such lesson to themselves. They resolved forthwith to make a pilgrimage to Florida, and quaff at morning, noon, and night, from the Fountain of Youth.

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THOUGHTS ON THE NATURE OF COMETS. The present age is characterized by new theories and speculations, and it is difficult to avoid imbibing a portion of its prevailing spirit. This fact, then, must be my apology for offering the following remarks on the nature of cometary bodies a subject at present replete with uncertainty, and therefore presenting ample scope for the visionary and the theorist to hazard conjecture, which, in default of more safe and serious investigation, may serve to amuse, if it fail to instruct. Science appears to have paused in her pursuit of this subject, satisfied, apparently, with the triumph of having successfully predicted the path and the return of one comet whose orbit extends beyond our system so far as our system is yet known to extend — and of two within it. In the mean time, the hypotheses of the ignorant will not be entirely useless, if they serve but to suggest a new fulcrum on which the lever of science may rest, or if they point out but the weight of an additional grain to increase the momentum necessary to move the world of doubt beneath which the truth is buried.

The subject at present is embarrassed with apparent contradictions. Down to the present day, the question remains subjudice, whether comets are solid, opaque bodies, or whether they are thin and transparent; some of the learned contending that a perfect occultation of a fixed star occurs when a comet passes between it and the spectator's eye - others affirming that no such occultation takes place, but that the fixed star is visible through the nucleus of the comet. From this difference of opinion has arisen the monstrous supposition, that some comets are solid, and others vaporous as if it were possible that bodies with natures diametrically opposite, could be governed by precisely the same law.

Scientific men have labored in vain to account for the embarrassing fact, that a vast body, drawing after it a train of 20°, 60°, and

even 100°, should not only produce no perceptible effect upon the motion of the planets near which it passes, but that such a body itself should be retarded in its exceedingly rapid course, and suffer an alteration in the diameter of its orbit, by the attraction of a single planet. The comet of Halley, in its return in 1759, was delayed in its approach to the sun, nearly one hundred days, by the attractive influence of Saturn, and nearly five hundred days by that of Jupiter. This fact has never been satisfactorily accounted for, and upon the supposition that comets are solid bodies, it is utterly inexplicable; for it would stand forth a solitary instance of opposition to all the known laws of motion by which the universe is governed. In this dilemma, astronomers are obliged to resort to the expedient of calling comets exceedingly small bodies, surrounded by a large and luminous atmosphere ; but such a supposition becomes highly improbable, when we consider at what an immense distance their nuclei are visible.

Again : It is the property of opaque bodies to project a shadow into space. The light from the sun falling upon the heavenly bodies in lines nearly parallel, causes their shadow to extend to an immense distance. Thus we perceive that the size of the earth's shadow suffers comparatively but a slight diminution in its passage to the moon; and there is little doubt but that a partial eclipse of the latter body would occur, were she more than five times her present distance from the earth. Now, since the tail spreads off from the comet in exactly the same direction in which the nucleus should project a shadow, it would seem that, if the nucleus were opaque, it should render a portion of the tail immediately behind it dark : but such an appearance, as far as I have been able to learn, has never been observed, even in the largest of these bodies.

From these considerations, I am inclined to suppose that the nucleus, or star, of a comet is not a solid, opaque body, but rather an accumulation in one point of the same matter as that of which the tail is composed, concentrated and coherent by the sun's attractions, or by some law resembling that which regulates chemical combinations and preferences ; and in that form — moving in vacuo, or nearly so obeying the general laws of motion. This idea contains nothing improbable, or contradictory to the established theory of matter and attraction. Of whatever matter the tails of comets be composed, * there is nothing absurd in supposing them to contain particles of greater or less density ; and if so, it is perfectly reasonable to conclude that the attraction of the sun would act more powerfully on those denser particles, and draw them forward with greater force. This would necessarily have the effect of causing a conglomeration of such particles exactly in that part of the comet where the nucleus now appears. And it is equally reasonable to suppose, that the rarer particles, being less strongly impelled by the sun's attraction, should obey that impulse more slowly, and form themselves into a train behind the nucleus, the ratio of their density determining their position, till the extreme end would become so rare as to be no longer visible. This refers to the comet's passage toward the sun ; the same cause, however, to a certain degree, would operate on its return. As a comet approaches its perihelion, its velocity is of course immensely increased, and the tail being but faintly affected by attraction, receives, in the acute turn of its orbit, a more powerful impulse of centrifugal force, and therefore would move foremost in the comet's passage from the sun, though necessarily diminished in length : and such we find is always actually the fact.

* Of this anon.

The question then arises, of what kind of matter are comets composed ? There seems to be but one which can reconcile the apparent incongruity of size not exerting strong attraction on other bodies, or which can bear out the contradictory assertions of astronomers respecting the transparency or opacity of the nuclei of comets and that one is, electric fluid, in that state in which it appears to us as the aurora borealis.

That the aurora borealis is electric fluid, rendered visible by the friction of the atmosphere, seems to be now scarcely doubted ; and we know that a spark from an electrical machine assumes the perfect appearance of a miniature aurora borealis in the nearly exhausted receiver of an air-pump. And when we consider that almost all bodies, by friction, become generators of electricity that the whole surface of our globe is one great manufactory - so to speak of electric fluid – it is evident that the immense quantity thus continually accumulating in the atmospheres of this and other inhabited worlds, must at length find some outlet — some safetyvalve to let off its superabundant streams. May not comets, then, afford the desired medium of keeping up the proper balance in this respect ? Arguments may be adduced, which go to prove that they do produce an effect upon our atmosphere, such as may be anticipated upon the supposition that these bodies are themselves electric. At all events, this supposition will enable us to account for many facts in natural philosophy, which otherwise appear to be perfectly enigmatical.

1. It appears, from researches made by M. Arrago, that those seasons in which comets have appeared, have been remarkably cold and unpleasant; and it is certain that the past year has borne ample testimony to the general fact. In what way is coincidence to be accounted for, unless by supposing that the comets collect from the atmospheres of the earth, and of the other planets which lie in their path, a large portion of the electric fluid, and, consequently, perhaps, latent heat which they contain ?

No slight force and probability are added to this supposition, by calling to mind what will readily be admitted by every one, that during the season which immediately preceded the last arrival of Halley's comet, a very unusual number of electrical phenomenæ appeared in our atmosphere. Rarely were such beautiful displays of the aurora borealis witnessed seldom were so many accidents from lightning recorded. It is a remarkable fact, that the year just elapsed has been unusually deficient in these occurrences.

2. The astronomer Massarotti,* considers comets capable of affording demonstration of a resisting medium in the heavens, and we may, without any very great stretch of the imagination, suppose the

Vide Encyclopædia Americana — article 'Comets.'

atmospheres of the planets to extend, in a highly rarified state, till they unite with each other. As far as experiments on atmospheric air have yet enabled us to judge, it would almost appear that its elasticity is unlimited; and in the higher regions, where all pressure is removed from it, except that which proceeds from the attraction of the body which it surrounds, there seems nothing improbable in supposing that a single particle may be so attenuated as to cover a surface of several square miles, yet sufficiently dense to serve as a conducting medium for the electric fluid.

Under these suppositions, we may account for the increased length of tail which comets exhibit, as they approach their perihelion. Řeceiving, as they pass, accumulations of electricity from the planets, their volume becomes enlarged, at the same time their velocity being accelerated through this ' resisting medium,' or rarified atmosphere, friction is produced, sufficient to render the electric fluid more brightly visible.

There is still another fact bearing on this part of our subject. It was stated by some of the European astronomers, that in observing Halley's comet with powerful telescopes, an appearance of three, or, as others affirmed, five tails, was observed. On any other than the electric theory, this would seem quite unaccountable; and many, indeed, were inclined to think that the philosophers were either deceiving or deceived. But considering the subject in the light in which it is here presented, what is more probable than to suppose such tails or streams of light to be currents of electric fluid, passing off from the atmospheres of the nearest planets, and becoming visible as they approached the comet, in consequence of the increased velocity which proximity must produce ?

3. Warm, moist air is a good conductor of electricity. Hence we find, that in the regions comprised within the torrid zone, thunder-storms are more frequent and more terrific than in higher latitudes. In connexion with this circumstance, looking upon comets as vast masses of electric fluid, it is not impossible that some light may be thrown upon the hitherto unexplained fact, that the tail of the same comet subtends a larger angle, when viewed from the equatorial regions, than it does from more northern or southern countries. The comet of 1768-9, as observed at Paris, exhibited a train of 60°. At the same time, from on board a ship between Cadiz and Teneriffe, it appeared to be 90°, and at the Isle of Bourbon, 970. It is difficult to say in what manner a highly electric atmosphere magnifies the comet's tail, without producing the same effect upon the other heavenly bodies; yet looking upon them as homogeneous, the fact appears to wear a less formidable aspect.

The last circumstance to be adverted to, is the well-known fact, that while all the other bodies of our system move round the sun in one direction, the comets appear bound by no such restriction. Some are direct some retrograde. This circumstance, if it has no other force, yet at least seems to militate against the probability of their being solid bodies — for if they were, why should they not follow the universal law by which all the bodies known to be solid are directed ? And if they are not solid bodies, it will at least appear probable, that the matter of which they are composed is more likely to be electric fluid than any other with which we are acquainted. And if the

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