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From The Saturday Review. bodies are recorded in the catalogue of com-
COMETS. *

ets, and the orbits of about a quarter of them The comet which has just ceased to at- have been determined with more or less actract attention has certainly some right to curacy:

Four only have been distinctly complain of the indifference of the English recognized on their re-appearance, of which public. It was scarcely, if at all, less bril- three lie within the limits of the planetary liant than that which glorified the autumn system, and the fourth, the famous comet of of 1858; and its tail was considerably more

Halley, reaches but a little way beyond the elongated. Like its predecessor, it has been orbit of Neptune. Halley had the honor of pronounced a new acquisition ; for no as- first predicting the re-appearance of a comet. tronomer has yet succeeded in identifying it He perceived the near approach to identity with any

which has visited us before. In of the calculated orbits of the comets of spite of all these attractions, the spectacle 1682 and 1607, and on searching the past appears a sort of failure when compared with records he found another earlier appearance the exhibition of 1858. The earlier of the recorded in 1531, which satisfied him that two recent comets was honored with more his comet had a period of about seventy-five than one leader in the Times, and was made years, and ought to re-appear towards the bethe subject of innumerable communications ginning of 1759. As the time approached, to that many-sided print, of every possible the problem was treated with more exactcalibre, from the calculations of accredited ness by the French philosopher Clairaut, astronomers to the speculations of the most who fixed the middle of April as the time ignorant and conceited observers of the one when the comet would approach most nearly absorbing phenomenon. This year, a lan-to the sun. He claimed a margin of thirty guid glance at the celestial visitor through a days for error in calculation, and exactly one binocular seems to have satisfied the curi- month before the predicted time Halley's osity of average Englishmen; and the last comet was found in its perihelion position. haze of the tail has been allowed to disap- This was the comet which again appeared, pear without a single flash of nonsense on

obedient to prediction, in 1835, and it is now the subject appearing in the Times. This as completely recognized a member of our contrast might be welcomed as a symptom system as any of the planets themselves. of greater sobriety of speculation having set

The instant that a new comet is announced, in with the Conservative reaction, were it the first efforts of astronomers are directed not for the fact that the injudicious luminary to a comparison of its observed course with of 1861 appeared in the height of the session the records of former appearances, and some of Parliament, while its predecessor burst notion of the multitude of these bodies may upon the world in the full swing of the Silly be formed from the fact that no comet since Season.

that of 1835 has been identified as an old Whatever the cause, it is matter for con- friend. The return of some of them has gratulation that the only literary product of been predicted with more or less certainty this recent apparition is a republication in a

from the form of their orbits, which in sevseparate form of what is decidedly the best eral instances have been ascertained to be resumé of all that is known of comets which clearly elliptical while others are certain to has yet appeared. The work to which we fly off to practically, if not absolutely, infirefer is an excerpt from Arago's Popular

nite distances ; but with the exception of the Astronomy, and contains perhaps the best few data which have thus been arrived at, chapters of a work which attempts, with

little is known of the track of comets besuccess second only to Sir John Herschel's, yond the general fact that they move at all to popularize astronomical science. The

sorts of inclinations to the plane of the solar history of observed comets stretches back as system, and, as often as not, in a direction far as the Chinese records of the first cen-'opposite to that which is common to all the tury. More than six hundred of these strange planets. One singular circumstance, indeed,

is known of a little comet, first calculated by * A Popular Treatise on Comets. By Francois Encke, which revolves in a period of about Arago. Translated and Edited by Admiral W. H. three years, and has occasionally excited Smyth and Robert Grant. London : Longmans. 1861.

some alarm by its anticipated proximity to

a

the earth. In less than a century its period | up by the sun itself. Newton himself spechas steadily diminished by about four days ulated on the possibility of comcts furnish-a fact from which astronomers have drawn ing the fuel of the central luminary, and atthe almost irresistible inference that the tributed the sudden appearance of previously planetary spaces are occupied by a rare re- unknown stars to a conflagration due to sisting medium, which must ultimately bring cometary interference. To come back to all the planets into collision with the sun. the earth, it is ascertained to be by no means

This rather meagre account is all that as- improbable that the globe may gather up tronomers have to tell us about the orbits of into its atmosphere some portions of the comets, and, except in negativing a host of tails of comets which approach inconvenpopular fallacies, they have been still less iently near. Certain remarkable dry fogs, successful in the inquiry into the composi- in 1783 and 1831, were, with insufficient tion of these anomalous bodies. Popular reason, attributed to this cause; and the curiosity concerns itself more with the ques- first observation of this year's comet was tion what comets are made of than with any said to have been preceded by a peculiar investigations of their erratic orbits. To the haze, which it was sought to connect with alarmists, the little that is known on this the comet itself. But all these minor influsubject ought to be especially grateful. ences, even if more satisfactorily established, Whatever comets are made of, they seem to are insignificant matters compared with the be of a very cobwebby texture. In 1770, a possibility, so often asserted, of a conflagracomet passed outside of the moon's orbit, tion to be caused by a collision with a blazwithin the moderate distance of a million ing comet; and the first point to be settled and a half miles from ourselves. If it had is whether comets are really incandescent been as heavy as the earth it would have luminous bodies. This problem was very prolonged the year by two or three hours. happily treated by Arago himself, who deIt did not add a single second to the period monstrated that comets owe at least a large of the carth's revolution and must have been portion, if not the whole, of their light to less than a four thousandth part of the weight the reflection of the solar rays. Their light of our globe. Another comet actually thrust has the quality of reflected light; and moreitself between Jupiter and his moons without over, when they disappear, it is not in the causing the smallest appreciable disturbance way in which a luminous body becomes inof their movements. Even the most bril- visible, by gradually subteuding an angle liant are transparent enough to allow stars too small to produce a sensible impression to be seen through the centre of the nucleus, of light, but by a much more sudden process and from these observations the inference caused by their increasing distance from the has been drawn that the substance of a sun, the centre of their illumination. Still comet is considerably less solid than a Lon- it is possible that some portion of a comet's

Perhaps the strangest phenome- light may be its own property, and those who non ever observed was the splitting of one prefer to fancy them as burning worlds may very familiar comet into two distinct bodies, still have some shreds of argument wherewhich went on in neighboring orbits without with to defend their hypothesis. But if they any special symptoms of an extraordinary are not bright, comets may at any rate be nature. These considerations rather tend to hot, and every one knows the superstition blunt the interest of the inquiry whether a about comet summers and comet vintages. comet is ever likely to come into collision Arago deals with this question as carefully with the earth ; but Arago re-assures the as with others of more pretension. A close timid with a calculation that the odds, in an analysis of meteorological records shows average case, are some hundreds of millions that the average temperature of comet years to one against the occurrence of such an has not been appreciably higher than that event. Still, it is not impossible ; and those of others, and that extreme cold has somewho delight in catastrophes which may be times been experienced during a comct's viewed at a distance will be rejoiced at the visit. Even the wild speculation that a prediction that, after an interval of an un- comet may some day drag us by its attracknown number of millions of years, several tion to infinitely remote regions of unwarmed of the best known comets must be swallowed | space, is considered with abundant gravity;

don fog.

and though it is admitted that a comet, if astronomers as much as they may have

puzit were only heavy enough, and if it came zled the earliest Chinese observers. Some near enough, might make a satellite of the would make them mere optical effects, withearth itself, the consolation is offered that out more substance of their own than a sunno such comet has ever been seen, and that beam shining in a darkened room. Newton if we were carried off to the most remote made the tail a mere vapor thrown off by regions of space, it is by no means certain the heat of the sun ; but neither this hythat the temperature of the earth would fall pothesis nor those of Kepler and Tycho so low as to extinguish human life. The Brahé were sufficient to account for some of experiment would not be a pleasant one to the most familiar facts. Biot and Gregory, try, and it is more comfortable to fall back Laplace and Delambre, all had theories which on the assurance which the nebulous char- are discussed and rejected by Arago, whose acter of comets affords against any appreci- chapter ends with a brief statement of his able disturbance of our orbit.

own solution of the problem, What is the A chapter upon tails almost completes the cause of a comet's tail ? The answer given history of comets which Arago compiled. is, “I do not know ;” and it is the only One thing is certain about them—they al- answer which astronomers have yet been ways appear denser at the edges than in the able to give to the enigma. centre-a phenomenon which can only be These are the main conclusions to be explained by regarding them as hollow coni- drawn from the work which has been so opcal or cylindrical cnvelopes of a certain de- portunely republished. They are not quite gree of transparency. But the way in which so ample as the hypotheses which have often they are thrown off at the rate of millions been sown broadcast by less-informed writof miles in an hour—the force which moves ers, but they comprise all that is known on them—the changes which they undergo- a subject which is perhaps the more fascithe tendency to remain in general opposite nating from the mystery which still hangs to the sun, in de nce of all mechanical about it. laws—are all matters which puzzle modern

SUBSTITUTE FOR Silver. – Two French | exposure to the atmosphere, or by any but the chemists, MM. De Ruolz and De Fontenay most powerful re-agents. It is without odor. have lately obtained, after several years' exper- Its specific gravity is a little less than that of

An alloy possessing these properties for small coin and for many industrial uses. It It can be supplied at a price forty per cent. less

silver. iments, a new alloy, which may be very useful

must be very useful to gold and silversmiths. is composed of one-third silver, twenty-five to than silver, and its greater hardness will give it thirty per cent. of nickel, and from thirty-seven a marked superiority. It may also serve as a to fifty-two per cent. of copper. The inventors substitute for gold-plated or silver-plated artipropose to call it tiers-argent, or tri-silver. Its cles, which are now so cominon on account of preparation is said to be a triumph of metallur- their cheapness, but which will not bear rc-platgical science. The three mctals, when simply ing more than a few times, and which are, in the melted together, form a compound which is not long run, sometimes more expensive than the homogencous; and to make the compound per- pure metal. The new alloy, however, will be fect, its inventors have been compelled to use most useful for small coin. Its preparation and phosphorus and certain solvents which they have coining are so difficult that the coin made of it not yet specificd. The alloy thus obtained is at cannot easily be counterfeited. Its hardness first vcry brittle ; it cannot be hammered or would render it more durable than silver; and drawn, and lacks thosc properties which are es- thus the expense of re-coining, and the heavy sential in malleable metals. But after the phos- loss arising from the wearing of our silver coinphorus is eliminated, the alloy perfectly resem- aye, would be greatly diminished. It is probables a simple metal, and possesses in a very high ble that this alloy would be more preferable for degree the qualities to which the precious metals small coins than nickel-the metal which is used owe their superiority. In color it resembles for the new Belgian coinage about to be issued. platinum, and is susceptible of a very high pol. Apart from the objectionable color of this latter ish. It possesses extreme hardness and tenacity. metal, there are other reasons why it would be It is ductile, malleable, very easily fused, emits desirable to cmploy an alloy similar to the one when struck a beautiful sound, is not affected by described above.

post hoc

From The Atheneum.

almost blind credulity may be attended with Another Letter to a Young Physician: to neither good nor evil consequence, but it indi

which are appended some other Medical cates a state of popular intelligence out of Papers. By James Jackson, M.D. Trüb- which charlatans have from time immemorial ner & Co.

made their profit. The readiness of illogical

minds to reason on insufficient data, and emThough Dr. Jackson's “ Letter to a Young brace the wildest conclusions of Physician” is not exactly a publication for ergo propter hoc” reasoning, which prothe drawing-room table, it is one of which claimed Joanna Stephens a public benefactor, we should gladly hear that it had found its placed Mrs. Mapp in her coach-and-four, bore way into the hands of every lady in the coun- witness to the cures of Ward and Taylor, and try. Scarcely any social change is more to testified that painted nails and slips of wood be desired than that women should be better could draw morbific virus from the human instructed on the theory of medicine, and the system, did not disappear together with faith arts and sciences pertaining to it. Led by in “metallic tractors.” It countenanced the custom and curiosity to dabble in physic, obscenities of Mesmer, built Graham's “Temthey are almost as ignorant of its first prin-ple of Health,” upheld the pernicious pracciples as were our grandmothers in the tenth tices of St. John Long, and in our time furdegree, who centuries since doctored their nishes Spirit-Rapping with its thousands of children and dependants with specifics com- believers. pounded of a hundred different ingredients. The time, we trust, is not far distant when Natural affection and domestic convenience a writer of competent attainments and immake them the nurses of the sick, and not partial judgment will offer the public a satunfrequently, in cases of emergency, they isfactory history of medicine, -not a compiare the only ministrants at hand to discharge lation wandering over thrice ten centuries of offices that would properly devolve on a reg- scientific darkness, with a show of erudition ularly trained medical adviser. Yet little or filched from Le Clerc and Freind ; but a no care is taken to procure them information, sound, honest history of medicine during the without which a mother will often be power- last hundred years, referring to the ancient less to afford comfort to a child struggling schools only to display the causes of their upon her breast with needless suffering. In- errors, and having for its chief object the exdeed, a proposal to instruct ladies in nosol- position of those facts and principles which, ogy and the mysteries of the pharmacopiæa even at the present unsatisfactory stage of would shock the delicacy or excite the ridi- medical science, recent investigations have cule of most persons able to bring about a conclusively ascertained. Until public inbetter state of things. The result of this un- telligence is better informed both as to what wise treatment of an important subject is, is really known, and as to the means by that, as a rule, gentlewomen regard a physi- which we may reasonably hope to attain cian's prescription with the same sort of su- further knowledge on subjects concerning perstition as was formerly expended on amu- which no one can be indifferent, ignorant lets and charms, and in pure simplicity believe pretenders, be they ambitious knaves or mere a dose of medicine to be a mysterious agent self-deluded enthusiasts, will find a submiscapable of driving disease out of the body. If sive crowd of worshippers and victims. In Dr. Allopath's pills are taken previous to the the mean time it is something to have a phyabatement of a fever, to Dr. Allopath's pills sician of reputation come forward and frankly the improvement is attributed ; if Dr. IIo- avow how far, and under what circumstances, mæopath's globule is administered an hour be- medical science can cope with disease. It is fore the advent of a refreshing sleep, Dr. Ho- well for the invalid of average education and mæopath’s globule gets all the credit of the sagacity to know that one of the most enchange for the better; and just as the cham- lightened physicians of the present century ber in which a patient recovers under the admits that all he can effect in the practice kindly efforts of nature has been presided of his profession is, in certain cases—such over by Dr. Allopathor Dr. Homæopath, so cases being by no means a majority of those the one or the other is held by the spectators that seek his treatment-to assist nature in to be a “wise man.” In a particular case this working her own cure :

“ When a surgeon is called to a man with that she needs. Just so, the physician, in a broken leg (writes Dr. Jackson], he places the larger number of cases under his care, the limb of his patient, and in some measure makes it his business to dispose of every his wbole body, in a fixed position, using thing relating to his patients in such a mansplints and bandages ; and then he watches ner as to give the best chance for the saluhim from day to day. He does not pretend tary operation of the natural powers. A that the processes of healing in the fractured good nurse, it may be said, may do the bone are brought into operation by the splints same. But the qualifications of a well-eduand bandages, nor by his watching. But he cated physician must enable him to take the has placed the injured parts under the cir- case with much greater advantage.” cumstances most favorable for healing ; and he watches that he may guard against every

Testy innovators, who are fond of railing thing which can interfere with the salutary at the intolerance of Orthodox Medicine, operations of nature, as well as that he may will do well to take a lesson of moderation give to her any support which he may think I from an orthodox physician.

Botton OF THE OCEAN.—Mr. Green, the like sunfish ; from those of the dullest hue, to famous diver, tells singular stories of his adven- the changeable dolphin; from the spots of the tures, when making search in the decp waters of leopard to the hues of the sunbeam ; from the the ocean. He gives some sketches of what he harmless minnow to the voracious shark. Some saw on the Silver Banks, near Hayti :

had heads like squirrels, others like cats and “The banks of coral on which my divings dogs; one of small size resembled a bull terwere made, are about forty miles in length, and rier. Some darted through the water like refrom ten to twenty in breadth.

teors, while others could scarcely be seen to “On this bank of coral is presented to the more diver one of the most beautiful and sublime “ To cnumerate and explain all the various scenes the eye ever beheld. The water varies kinds of fish I beheld while diving on these from ten to one hundred feet in depth, and is so banks, would, were I cnough of a naturalist so clear, that the diver can see from two to three to do, require more space than my limits will hundred feet, when submerged, with little ob- allow, for I am convinced that inost of the struction to the sight.

kinds of fish which inhabit the tropical seas “ The bottom of the ocean, in many places on

can be found there. The sun-fish, saw-fish, these banks, is as smooth as a marble floor ; in star-fish, white shark, ground shark, blue or others it is studded with coral columns, from shovel-nose sharks, were often seen. There ten to one hundred feet in height, and from one

were also fish which resembled plants, and reto eighty feet in diameter. The tops of those mained as fixed in their position as a shrub. more lofty support a myriad of pyramidal pen- The only power they possessed was to open dants, each forming a myriad more ; giving the and shut when in danger. Some of them rereality to the imaginary abode of 'some water sembled the rose in full bloom, and were of all nymph. In other places the pendants form hues. There were ribbon fish, from four to five arch after arch, and as the diver stands on the inches to three feet in length. Their cyes are bottom of the ocean, and gazes through these very large, and protrude like those of the frog. into the deep winding avenue, he feels that they Another fish was spotted like the leopard, from fill him with as sacred an awe as if he were in three to ten feet long. They build their houses some old cathedral, which had long been buried like the beaver, in which they spawn, and the beneath 'old ocean's wave.' Here and there, male or female watches the ova'till it hatches. the coral extends even to the surface of the I saw many specimens of the green turtle, some water, as if those loftier columns were towers five feet long, which I should think would weigh belonging to those stately temples now in ruins. from four to five hundred pounds.”

“ There were countless varieties of diminutive trees, shrubs, and plants, in every crevice of the corals wirere the water had deposited the least earth. They were all of a faint hue, owing to During the siege of Sevastopol, a Russian the pale light they received, although of every shell buried itself in the side of a bill without shade, and entirely different from plants I am the city, and opened a spring. A little fountain familiar with, thắt vegetate upon dry land. bubbled forth where the cannon-shot had fallen, One in particular attracted my attention; it re- and during the remainder of the siege afforded sembled a sea-fan of immense size, of variegated to the thirsty troops who were stationed in that colors, and of the most brilliant hue.

vicinity an abundant supply of pure cold water. “ The fish which inhabited those silver banks, Thus the missile of death from an enemy, under I found as different in kind, as the scenery was the direction of an overruling Providence, proved varied. They were of all forms, colors, and an almoner of life to the parched and weary sizes—from the symmetrical goby, to the globe- ! soldier of the Allies.

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