,illustration3 ,fig4 #a4 ,,the ,,solar ,,system4 ,frontispiece4 ,,comets ,,and ,,meteors3 ,,their ,,phenomena ,,in ,,all ,,ages2 ,,their ,,mutual ,,relations2 ,,and ,,the ,,theory ,,of ,,their ,,origin4 ,,by ,,daniel ,,kirkwood1 ,,ll4,d41 ,,professor ,,of ,,mathematics ,,in ,,indiana ,,university1 ,,and ,,author ,,of ,,meteoric ,,astronomy4 ,illustration ,,philadelphia3 ,j4 ,b4 ,,lippincott ,,co4 #ahgc4 ,entered according to ,act of ,congress1 in the year #ahgc1 by ,,daniel ,,kirkwood1 ,,ll4,d41 ,in the ,office of the ,librarian of ,congress at ,washington4 ,,preface4 ,the origin of meteoric astronomy1 as a science1 dates from the memorable star-shower of #ahcc4 ,soon after that brilliant display it was found that similar phenomena had been witnessed1 at nearly regular intervals1 in former times4 ,this discovery led at once to another no less important1 viz43 that the nebulous masses from which such showers are derived revolve about the sun in paths intersecting the earth's orbit4 ,the theory that these meteor-clouds are but the scattered fragments of disintegrated comets was announced by several astronomers in #ahfg3--;a theory confirmed in a remarkable manner by the shower of meteors from the dbris of ,biela's comet on the #bgth of ,november1 #ahgb4 ,to gratify the interest awakened in the public mind by the discoveries here named1 is the main design of the following work4 ,among the subjects considered are1 cometary astronomy2 aerolites1 with the phenomena attending their fall2 the most brilliant star-showers of all ages2 and the origin of comets1 aerolites1 and falling stars4 ,it may be proper to remark that the language used by the writer in a volume#a published several years since1 and now nearly out of print1 has been occasionally adopted in the following treatise4 ,,bloomington1 ,,indiana1 ,april1 #ahgc4 #a ,meteoric ,astronomy4 ,,contents4 ,,page4 ,,preface #c ,,chapter ,i4 ,a ,,general ,,view ,,of ,,the ,,solar ,,system #i ,,chapter ,,ii4 ,,comets #ac ,,comets ,,visible ,,in ,,the ,,day-,,time #ae ,,periodic ,,comets #ah ,,chapter ,,iii4 ,,comets ,,whose ,,elements ,,indicate ,,periodicity1 ,,but ,,whose ,,returns ,,have ,,not ,,been ,,recognized #ca ,,chapter ,,iv4 ,,other ,,remarkable ,,comets #ci ,,chapter ,v4 ,,the ,,position ,,and ,,arrangement ,,of ,,cometary ,,orbits #dc ,,chapter ,,vi4 ,,the ,,disintegration ,,of ,,comets #di ,,chapter ,,vii4 ,,meteoric ,,stones #eg ,,chapter ,,viii4 ,,shooting-,,stars--,,meteors ,,of ,,november #ad #fi ,,chapter ,,ix4 ,,other ,,meteoric ,,streams #hb ,,chapter ,x4 ,,the ,,origin ,,of ,,comets ,,and ,,meteors #id ,i4 ,,comets4 ,,comets ,,and ,,meteors4 ,,chapter ,i4 ,a ,,general ,,view ,,of ,,the ,,solar ,,system4 ,a descriptive treatise on ,,comets and ,,meteors may properly be preceded by a brief general view of the planetary system to which these bodies are related1 and by which their motions1 in direction and extent1 are largely influenced4 ,,the ,,solar ,,system consists of the sun1 together with the planets1 comets1 and meteors which revolve around it as the centre of their motions4 ,the sun is the great controlling orb of this system1 and the source of light and heat to its various members4 ,its magnitude is one million three hundred thousand times greater than that of the earth1 and it contains more than seven hundred times as much matter as all the planets put together4 ,mercury is the nearest planet to the sun2 its mean distance being about #ce1djj1jjj miles4 ,its diameter is #cjjj miles1 and it completes its orbital revolution in #hh days4 ,venus1 the next member of the system1 is sometimes our morning and sometimes our evening star4 ,its magnitude is almost exactly the same as that of the earth4 ,it revolves round the sun in #bbe days4 ,the earth is the third planet from the sun in the order of distance2 the radius of its orbit being about #ib1jjj1jjj miles4 ,it is attended by one satellite1--the moon1--the diameter of which is #bafj miles4 ,mars is the first planet exterior to the earth's orbit4 ,it is considerably smaller than the earth1 and has no satellite4 ,it revolves round the sun in #fhg days4 ,the ,asteroids4--,since the commencement of the present century a remarkable zone of telescopic planets has been discovered immediately exterior to the orbit of ,mars4 ,these bodies are extremely small2 some of them probably containing less matter than the largest mountains on the earth's surface4 #aca members of the group are known at present1 and the number is annually increasing4 ,jupiter1 the first planet exterior to the asteroids1 is nearly #ejj1jjj1jjj miles from the sun1 and revolves round it in a little less than #ab years4 ,this planet is #hf1jjj miles in diameter1 and contains more than twice as much matter as all the other planets1 primary and secondary1 put together4 ,jupiter is attended by four moons or satellites4 ,saturn is the sixth of the principal planets in the order of distance4 ,its orbit is about #djj1jjj1jjj miles beyond that of ,jupiter4 ,this planet is attended by eight satellites1 and is surrounded by three broad flat rings4 ,saturn is #gc1jjj miles in diameter1 and its mass or quantity of matter is more than that of all the other planets except ,jupiter4 ,uranus is at double the distance of ,saturn1 or nineteen times that of the earth4 ,its diameter is about #cd1jjj miles1 and its period of revolution #hd years4 ,it is attended by at least four satellites4 ,neptune is the most remote known member of the system2 its distance being #b1hjj1jjj1jjj miles4 ,it is somewhat larger than ,uranus2 has certainly one satellite1 and probably several more4 ,its period is about #afe years4 ,a cannon-ball flying outward from the sun at the uniform velocity of #ejj miles per hour would not reach the orbit of ,neptune in less than #fci years4 ,these planets all move round the sun in the same direction1--from west to east4 ,their motions are nearly circular1 and also nearly in the same plane4 ,their orbits1 except that of ,neptune1 are represented in the frontispiece4 ,it is proper to remark1 however1 that all representations of the solar system by maps and planetariums must give an exceedingly erroneous view either of the magnitudes or distances of its various members4 ,if the earth1 for instance1 be denoted by a ball half an inch in diameter1 the diameter of the sun1 according to the same scale 7#af1jjj miles to the inch71 will be between four and five feet2 that of the earth's orbit1 about #ajjj feet2 while that of ,neptune's orbit will be nearly six miles4 ,to give an accurate representation of the solar system at a single view is therefore plainly impracticable4 ,,the ,,zodiacal ,,light4--,this term was first applied by ,dominic ,cassini1 in #afhc1 to a faint nebulous aurora1 somewhat resembling the milky way1 apparently of a conical or lenticular form1 having its base toward the sun and its axis nearly in the direction of the ecliptic4 ,the most favorable time for observing it is when its axis is most nearly perpendicular to the horizon4 ,this1 in our latitudes1 occurs in ,march1 for the evening1 and in ,october1 for the morning4 ,the angular distance of its vertex from the sun is frequently seventy or eighty degrees1 while sometimes1 though rarely 7except within the tropics71 it exceeds even one hundred degrees4 ,it was noticed in the latter part of the #afth century by ,tycho ,brahe4 ,the first accurate description of the phenomenon was given1 however1 by ,cassini4 ,this astronomer supposed the appearance to be produced by the blended light of innumerable bodies too small to be separately observed1--a theory still very generally accepted4 ,in other words1 the zodiacal light is probably a swarm of infinitesimal planets2 the greater part of the cluster being interior to ,mercury's orbit4 ,the distances between the different members of our planetary system1 vast as they may seem1 sink into insignificance when compared with the intervals which separate us from the so-called fixed stars4 ,alpha ,centauri1 the nearest of those twinkling luminaries1 is #gjjj times more distant than ,neptune from the sun4 ,even light itself1 which moves #ahe1jjj miles in a second1 is more than three years in traversing the mighty interval4 ,,chapter ,,ii4 ,,comets4 ,the term comet--which signifies literally a hairy star--may be applied to all bodies that revolve about the sun in very eccentric orbits4 ,the sudden appearance1 vast dimensions1 and extraordinary aspect of these celestial wanderers1 together with their rapid and continually varying motions1 have never failed to excite the attention and wonder of all observers4 ,nor is it surprising that in former times1 when the nature of their orbits was wholly unknown1 they should have been looked upon as omens of impending evil1 or messengers of an angry ,deity4 ,even now1 although modern science has reduced their motions to the domain of law1 determined approximately their orbits1 and assigned in a number of instances their periods1 the interest awakened by their appearance is in some respects still unabated4 ,the special points of dissimilarity between planets and comets are the following3--,the former are dense1 and1 so far as we know1 solid bodies2 the latter are many thousand times rarer than the earth's atmosphere4 ,the planets all move from west to east2 many comets revolve in the opposite direction4 ,the planetary orbits are but slightly inclined to the plane of the ecliptic2 those of comets may have any inclination whatever4 ,the planets are observed in all parts of their orbits2 comets1 only in those parts nearest the sun4 ,the larger comets are attended by a tail1 or train of varying dimensions1 extending generally in a direction opposite to that of the sun4 ,the more condensed part1 from which the tail proceeds1 is called the nucleus2 and the nebulous envelope immediately surrounding the nucleus is sometimes termed the coma4 ,these different parts are seen in ,fig4 #b1 which represents the great comet of #ahaa4 ,illustration3 ,fig4 #b4 ,,the ,,great ,,comet ,,of #ahaa4 ,zeno1 ,democritus1 and other ,greek philosophers held that comets were produced by the collection of several stars into clusters4 ,aristotle taught that they were formed by exhalations1 which1 rising from the earth's surface1 ignited in the upper regions of the atmosphere4 ,this hypothesis1 through the great influence of its author1 was generally received for almost two thousand years4 ,juster views1 however1 were entertained by the celebrated ,seneca1 who maintained that comets ought to be ranked among the permanent works of nature1 and that their disappearance was not an extinction1 but simply a passing beyond the reach of our vision4 ,the observations of ,tycho ,brahe first established the fact that comets move through the planetary spaces far beyond the limits of our atmosphere4 ,the illustrious ,dane1 however1 supposed them to move in circular orbits4 ,kepler1 on the other hand1 was no less in error in considering their paths to be rectilinear4 ,james ,bernoulli supposed comets to be the satellites of a very remote planet1 invisible on account of its great distance1--such satellites being seen only in the parts of their orbits nearest the earth4 ,still more extravagant was the hypothesis of ,descartes1 who held that they were originally fixed stars1 which1 having gradually lost their light1 could no longer retain their positions1 but were involved in the vortices of the neighboring stars1 when such as were thus brought within the sphere of the sun's illuminating power again became visible4 ,comets visible in the daytime4 ,comets of extraordinary brilliancy have sometimes been seen during the daytime4 ,at least thirteen authentic instances of this phenomenon have been recorded in history4 ,the first was the comet which appeared about the year #dc ,b4,c41 just after the assassination of ,julius ,csar4 ,the ,romans called it the ,julium ,sidus1 and regarded it as a celestial chariot sent to convey the soul of ,csar to the skies4 ,it was seen two or three hours before sunset1 and continued visible for eight successive days4 ,the great comet of #aajf1 described as an object of terrific splendor1 was seen simultaneously with the sun1 and in close proximity to it4 ,dr4 ,halley supposed this and the ,julian comet to have been previous visits of the great comet of #afhj4 ,in the year #adjb two comets appeared1--one about the middle of ,february1 the other in ,june1--both of which were visible while the sun was above the horizon4 ,one was of such magnitude and brilliancy that the nucleus and even the tail could be seen at midday4 ,the comet of #adgb1 one of the most splendid recorded in history1 was visible in full daylight1 when nearest the earth1 on the #bast of ,january4 ,this comet1 according to ,laugier1 moves very nearly in the plane of the ecliptic1 its inclination being less than two degrees4 ,its least distance from our globe was only #c1cjj1jjj miles4 ,the comet of #aecb1 supposed by some to be identical with that of #affa1 was also visible in full sunshine4 ,the apparent magnitude of its nucleus was three times greater than that of ,jupiter4 ,the comet of #aegg was seen with the naked eye by ,tycho ,brahe before sunset4 ,it was by observations on this body that ,aristotle's doctrine in regard to the origin1 nature1 and distance of comets was proved to be erroneous4 ,it was simultaneously observed by ,tycho at ,oranienberg1 and ,thaddeus ,hagecius at ,prague2 the points of observation being more than #djj miles apart1 and nearly on the same meridian4 ,the comet was found to have no sensible diurnal parallax2 in other words1 its apparent place in the heavens was the same to each observer1 which could not have been the case had the comet been less distant than the moon4 ,the comet which passed its perihelion on the #hth of ,november1 #afah1 was distinctly seen by ,marsilius when the sun was above the horizon4 ,the great comet of #agdd was seen without the aid of a glass at one o'clock in the afternoon1--only five hours after its perihelion passage4 ,the diameter of this body was nearly equal to that of ,jupiter4 ,it had six tails1 the greatest length of which was about #cj1jjj1jjj miles1 or nearly one-third of the distance of the earth from the sun4 ,the spaces between the tails were as dark as the rest of the heavens1 while the tails themselves were bordered with a luminous edging of great beauty4 ,the great comet of #ahdc was distinctly visible to the naked eye1 at noon1 on the #bhth of ,february4 ,it appeared as a brilliant body1 within less than two degrees from the sun4 ,this comet passed its perihelion on the #bgth of ,february1 at which time its distance from the sun's surface was only about one-fourth of the moon's distance from the earth4 ,this is the nearest approach to the sun ever made by any known comet4 ,the velocity of the body in perihelion was about #a1bhj1jjj miles an hour1 or nearly nineteen times that of the earth in its orbit4 ,the apparent length of its tail was sixty-five degrees1 and its true length #aej1jjj1jjj miles4 ,the first comet of #ahdg1 discovered by ,mr4 ,hind1 was also seen near the sun on the day of its perihelion passage4 ,that discovered by ,klinkerfues on the #ajth of ,june1 #ahec1 and which passed its perihelion on the #ast of ,september1 was seen at ,olmutz in the daytime1 ,august #ca1 when only twelve degrees from the sun4 ,after passing its perihelion1 it was again observed1 at noon1 on the #b;d1 #c;d1 and #dth of ,september4 ,finally1 the great comet of #ahfa was seen before sunset1 on ,monday evening1 ,july #a1 by ,rev4 ,henry ,w4 ,ballantine1 of ,bloomington1 ,indiana4 ,it was again detected on the following evening just as the sun was in the horizon4 ,besides the thirteen comets which we have enumerated1 at least four others have been seen in the daytime2 all1 however1 under peculiar circumstances4 ,seneca relates that during a great solar eclipse1 #fc years before our era1 a large comet was observed not far from the sun4 ,philostorgius says that on the #aith of ,july1 ,a4,d4 #dah1 when the sun was eclipsed and stars were visible1 a great comet1 in the form of a cone1 was discovered near that luminary1 and was afterwards observed during the nights4#b ,the comet which passed its perihelion on the #ahth of ,november1 #ahbf1 was observed by both ,gambart and ,flaugergues to transit the solar disk1--the least distance of the nucleus from the sun's surface being about #b1jjj1jjj miles4 ,the second comet of #ahai and the comet of #ahbc are both known in like manner to have passed between the sun and the earth4 ,unfortunately1 however1 the transits were not observed4 #b ,hind4 ,a few cometary orbits are hyperbolas1 more ellipses1 and a still greater number parabolas4 ,comets moving in ellipses remain permanently within the limits of solar influence4 ,others1 however1 visit our system but once1 and then pass off to wander indefinitely in the sidereal spaces4 ,comets of known periodicity4 ,i4 ,halley's ,comet4 ,as comets are subject to great changes of appearance1 one can never be identified by any description of its magnitude1 brilliancy1 etc41 at the time of a previous return4 ,this can be done only by a comparison of orbits4 ,if1 for example1 we find the elements of an orbit very nearly corresponding in every particular with those of a former comet1 there is a degree of probability1 amounting almost to certainty1 that the two are identical4 ,sir ,isaac ,newton1 in his ,principia1 published shortly after the appearance of the comet of #afhb1 explained how the periods of those mysterious visitors might thus be ascertained1 thus directing the attention of astronomers to the subject4 ,dr4 ,halley soon after undertook a thorough discussion of all the recorded cometary observations within his reach4 ,in the course of his investigations he discovered that the path of the comet observed by ,kepler in #afjg coincided almost exactly with that of the one which passed its perihelion in #afhb4 ,hence he concluded that they were the same4 ,he found also that the comet of #aeca1 whose course had been particularly observed by ,apian1 moved in the same path4 ,the interval between the consecutive appearances being nearly #gf years1 ,halley announced this as the time of the comet's revolution1 and boldly predicted its return in #ageh or #agei4 ,the law of universal gravitation had at this time just been discovered and announced4 ,but although its application to the determination of planetary and cometary perturbations had not been developed1 ,halley was well aware that the attractive influence of ,jupiter and ,saturn might accelerate or retard the motion of the comet1 so as to produce a considerable variation in its period4 ,during the interval from #afhb to #agei1 the application of the higher mathematics to problems in physical astronomy had been studied with eminent success4 ,the disturbing effect of the two large planets1 ,jupiter and ,saturn1 was computed with almost incredible labor by ,clairaut1 ,lalande1 and ,madame ,lepaute4 ,the result as announced by ,clairaut to the ,academy of ,sciences in ,november1 #ageh1 was that the period must be #fah days longer than that immediately preceding1 and that the comet accordingly would pass its perihelion about the #acth of ,april1 #agei4 ,it was stated1 however1 that1 being pressed for want of time1 they had neglected certain quantities which might somewhat affect the result4 ,the comet1 in fact1 passed its perihelion in ,march1 within less than a month of the predicted time4 ,when it is considered that the attraction of the earth was not taken into the account1 and that ,uranus1 whose influence must have been sensible1 had not then been discovered1 this must certainly be regarded as a remarkable approximation4 ,but during the next interval of #gf years the theory of planetary perturbations had been more perfectly developed4 ,the masses of ,jupiter and ,saturn had been determined with greater accuracy1 and ,uranus had been added to the known members of the planetary system4 ,a nearer approximation to the exact time of the comet's perihelion passage in #ahce was therefore to be expected4 ,prizes were offered by two of the learned societies of ,europe--the ,academy of ,sciences at ,turin1 and the ,french ,institute--for the most perfect discussion of its motions4 ,that of the former was awarded to ,damoiseau1--that of the latter to ,pontecoulant4 ,the times assigned by these distinguished mathematicians for the comet's perihelion passage were very nearly the same1 and differed but a few days from the true time4 ,had the present received mass of ,jupiter been used in the calculations1 ,pontecoulant1 it is believed1 would not have been in error as much as #bd hours4 ,it may be proper to remark that1 during the entire period from #agei to #ahce1 the position of ,neptune was such that it could produce no considerable effect on the motion of the comet4 ,this interesting object will again return about #aiaa4 ,the visit of #aeca was the earliest that ,halley succeeded in determining with any degree of certainty4 ,peter ,apian1 by whom it was at that time observed1 was the first ,european to ascertain the fact that1 as a general thing1 the tails of comets are turned from the sun4#c ,to confirm this discovery1 he carefully followed the body in its progress through the constellations4 ,by means of his recorded observations ,halley was enabled to identify this comet with that of #afjg and #afhb4 ,the great comet of #adef he conjectured to be the same1 from the date of its appearance4 ,pingr subsequently confirmed this suspicion by a careful examination of the few trustworthy records that could be collected from the writers of that period4 #c ,the ,chinese1 however1 as appears from ,biot's researches1 had observed the same fact #gjj years earlier4 ,see ,humboldt's ,cosmos1 vol4 iv4 7,bohn's ed471 p4 #edd4 ,from the earlier descriptions of this comet we infer that its brilliancy is gradually diminishing4 ,in #adef its tail1 which was slightly curved like a sword or sabre1 extended two-thirds of the distance from the horizon to the zenith4 ,the appearance of such an object1 in a grossly superstitious age1 excited throughout ,europe the utmost consternation4 ,the ,moslems had just taken ,constantinople1 and were threatening to advance westward into ,europe4 ,pope ,calixtus ,,iii41 regarding the comet as confederate with the ,turk1 ordered prayers to be offered three times a day for deliverance from both4 ,the alarm1 however1 was of short duration4 ,within ten days of its appearance the comet reached its perihelion4 ,receding from the sun1 the sword-like form began to diminish in brilliancy and extent2 and finally1 to the great relief of ,europe1 it entirely disappeared4 ,the perihelion passage of #adef was1 until recently1 the earliest known4 ,it was shown by ,laugier1 however1 in #ahdc1 that among the notices of comets extracted by ,edward ,biot from the ,chinese records1 were observations of a body in #acgh1 which was undoubtedly the comet of ,halley4 ,further researches among these annals enabled the same astronomer to recognize two ancient returns1 one in #gfj1 the other in #dea4 ,still more recently the distinguished ,english astronomer1 ,mr4 ,hind1 has traced back the returns to the year #aa ,b4,c4 ,he remarks1 however1 that previous to that epoch1 the ,chinese descriptions of comets are too vague to aid us in tracing any more ancient appearances1 and that ,european writers of these remote times render us no assistance4 ,let us now inquire whether the comet had probably made any former approach to the sun in an orbit nearly identical with the present4 ,it is well known that the modern period of this body is considerably less than the ancient4 ,thus1 the mean period since ,a4,d4 #adef has been #ge4hh years2 while from #aa ,b4,c4 to #adef ,a4,d4 it was #gg4bg years4 ,in determining the approximate dates of former returns1 the ancient period should evidently be employed4 ,now1 it is a remarkable fact that of more than #gj comets1#d or objects supposed to be comets1 whose appearance was recorded during the six centuries immediately preceding the year #aa ,b4,c41 but one--that of #aff ,b4,c4--was observed at a date corresponding nearly to that of a former return of ,halley's comet4 ,of this object it is merely recorded that a torch was seen in the heavens4 ,whether this was a comet or some other phenomenon1 it is impossible to determine4 ,but as the comet of ,halley was more brilliant in ancient than in modern times1 it seems highly improbable that seven consecutive returns of so conspicuous an object should have been unrecorded1 especially as twelve comets per century#e were observed during the same period4 ,it would appear1 therefore1 that the perihelion passage of #aa ,b4,c4 was in fact the first ever made by the comet1 or at least the first in an orbit nearly the same as the present4 #d ,see the ,catalogues of ,chambers and ,williams4 #e ,the average number4 ,the motion of ,halley's comet is retrograde4 ,the point of its nearest approach to the sun is situated within the orbit of ,venus4 ,its greatest distance from the centre of the system is nearly twice that of ,uranus1 or #cf times that of the earth4 ,the comet is1 consequently1 subject to great changes of temperature4 ,when nearest the sun its light and heat are almost four times greater than the earth's2 when most remote1 they are #abjj times less4 ,in the former position1 the sun would appear much larger than to us2 in the latter1 his apparent diameter would not greatly exceed that of ,jupiter1 as viewed from the earth4 ,it would be difficult to conjecture what the consequences might be1 were our planet transported to either of these extremes of the cometary path4 ,in the perihelion1 the waters of the ocean would undoubtedly be reduced to a state of vapor2 in the aphelion1 they would be solidified by congelation4 ,,ii4 ,encke's ,comet4 ,it was formerly supposed that all comets have their aphelia far beyond the limits of the planetary system4 ,in #ahah1 however1 a small comet was discovered by ,pons1 the orbit of which was subsequently found to be wholly interior to that of ,jupiter4 ,its elements were presented by ,bouvard1 in #ahai1 to the ,board of ,longitude at ,paris4 ,the form and position of the orbit were immediately found to correspond with those of a comet observed by several astronomers in #ahje4 ,the different appearances were consequently regarded as returns of the same body4 ,its elliptic orbit was calculated by ,encke1 who found its period to be only about three years and four months4 ,its perihelion is within the orbit of ,mercury2 its aphelion1 between the asteroids and the orbit of ,jupiter4 ,encke's comet is invisible to the naked eye1 except in very favorable circumstances2 it has no tail2 its motion1 like that of the planets1 is from west to east2 and its orbit is inclined about #ac to the ecliptic4 ,a comparison of the successive periods of this interesting object has led to the discovery that its time of revolution is gradually diminishing2 a fact regarded by ,encke and other astronomers as indicating the existence of an ethereal medium4 ,,iii4 ,biela's ,comet4 ,the discovery of ,encke's comet of short period was followed1 in #ahbf1 by that of another1 whose revolution is completed in about six years and eight months4 ,it was observed on the #bgth of ,february1 by ,m4 ,biela1 an ,austrian officer2 accordingly it has since been known as ,biela's comet4 ,on computing its elements and comparing them with those of former comets1 it was found to have been observed in #aggb and #ahje4 ,damoiseau having calculated the dimensions of the comet's elliptic path and the time of its return1 announced as the result of his computations the remarkable fact that the orbits of the earth and comet intersect each other1 and that the comet would cross the earth's path on the #bith of ,october1 #ahcb4 ,this produced no little alarm among the uneducated1 especially in ,france4 ,even some journalists are said to have predicted the destruction of our globe by a collision with the comet4 ,when the latter1 however1 passed the point of intersection at the predicted time1 the earth was at a distance of #ej1jjj1jjj miles4 ,at the return of #ahde-f1 ,biela's comet exhibited a most remarkable appearance4 ,instead of a single comet1 it appeared as two distinct bodies moving together side by side1 at a distance from each other somewhat less than that of the moon from the earth4 ,astronomers1 anxious to determine whether the cometary fragments had continued separate during an entire revolution1 awaited the next return with no ordinary interest4 ,the two bodies appeared at the predicted time 7,september1 #aheb72 their distance apart having increased to #a1bej1jjj miles4 ,in #ahei the comet1 on account of its proximity to the sun1 entirely escaped detection4 ,at the return in #ahfe-f the position of the object was quite favorable for observation1 yet the search of astronomers was again unsuccessful4 ,in #ahgb the body escaped detection both in ,europe and ,america4 ,one fragment was seen1 however1 at ,madras1 ,india1 on the mornings of the #b;d and #c;d of ,december1--several weeks after its perihelion passage4 ,the comet's non-appearance in #ahff and its greatly diminished magnitude in #ahgb leave no room to doubt its progressive dissolution4 ,this subject will again be referred to in discussing the phenomena of meteoric showers4 ,,iv4 ,faye's ,comet4 ,on the #bb;d of ,november1 #ahdc1 ,m4 ,faye1 of the ,paris ,observatory1 discovered a comet1 which was shown by ,dr4 ,goldschmidt to revolve in an elliptic orbit1 the perihelion of which is exterior to the orbit of ,mars1 and the aphelion immediately beyond that of ,jupiter4 ,the eccentricity is1 therefore1 less than that of any other comet previously discovered4 ,its period is about #g years and #e months4 ,it is possible that a comet moving in a parabola or hyperbola1 with the sun in the focus1 may be thrown into an elliptic orbit by the disturbing influence of ,jupiter or one of the other large planets4 ,the celebrated ,leverrier undertook to determine whether the comet of ,faye had in this manner been recently fixed as a permanent member of the solar system4 ,he found that it could not have been so introduced since #agdg1 and1 consequently1 that it must have completed at least thirteen revolutions before its discovery4 ,this comet has been observed at each return from #ahdc to the present time4 ,v4 ,de ,vico's ,comet4 ,on the #bb;d of ,august1 #ahdd1 ,de ,vico1 of ,rome1 discovered a comet whose orbit is included between those of the earth and ,jupiter4 ,its period is #aiif days1 or about #e-a_/b years4 ,this body1 from some cause1--perhaps a gradual dissolution1--has not been observed at any subsequent return4 ,,vi4 ,brorsen's ,comet4 ,on the #bfth of ,february1 #ahdf1 ,mr4 ,brorsen1 of ,kiel1 discovered a faint comet1 the mean distance and period of which are almost identical with those of ,de ,vico's4 ,this comet was not observed during the perihelion passage of #ahea1 on account of its unfavorable position with respect to the sun4 ,it has1 however1 been subsequently detected4 ,,vii4 ,d',arrest's ,comet4 ,dr4 ,d',arrest discovered a comet on the #bgth of ,june1 #ahea1 which was soon found to move in an elliptic orbit1 with a period of about #f-a_/b years4 ,it entirely escaped observation1 both in ,europe and ,america1 during its perihelion passage in #aheg4 ,it was observed1 however1 at the ,cape of ,good ,hope4 ,its invisibility in #ahfd was due to its unfavorable position4 ,at its return in #ahgj1 it was first seen on the #cast of ,august1 by ,dr4 ,winnecke1 of ,carlsruhe4 ,,viii4 ,tuttle's ,comet4 ,a faint telescopic comet was discovered at the ,observatory of ,harvard ,college1 on the evening of ,january #d1 #aheh1 by ,mr4 ,h4 ,p4 ,tuttle4 ,the same body was independently found one week later by ,dr4 ,bruhns1 of ,berlin4 ,from observations made at ,cambridge1 ,massachusetts1 and ,ann ,arbor1 ,michigan1 its elements were soon computed by different astronomers2 the result in each case coinciding so closely with the elements of the second comet of #agij1 as to place its identity wholly beyond doubt4 ,its period is nearly #ac years and #h months4 ,it had returned1 therefore1 without detection1 in the years #ahjc1 #ahag1 #ahca1 and #ahdd4 ,on its approach to perihelion in #ahga1 it was first detected by ,m4 ,borelly1 of ,marseilles4 ,,ix4 ,winnecke's ,comet4 ,the second comet of #aheh was discovered on the #hth of ,march1 by ,dr4 ,winnecke1 of ,bonn4 ,this proved to be identical with the third comet of #ahai1 whose period was computed by ,encke to be about #e-a_/b years4 ,it had therefore returned unperceived no less than six times between #ahai and #aheh4 ,at its return in #ahfc it again escaped detection4 ,the perihelion passage of #ahfi was made on the #cjth of ,june4 ,the comet was seen as early as ,april #ac1 and1 after passing the sun1 as late as ,october #aa4 ,schnfeld states that in part of ,april and ,may it appeared to have not one1 but several1 centres of condensation1 and ,vogel says that1 in the beginning of ,june1 it had a much greater resemblance to a star-cluster than to a nebula4 ,this phenomenon1 it may be remarked1 bore a striking resemblance to the appearances observed in the comets of #chi1 #afah1 and #affa4 ,x4 ,tempel's ,comet4 ,on the #aith of ,december1 #ahfe1 ,m4 ,tempel1 of ,marseilles1 discovered a small comet1 which continued visible four weeks1 passing its perihelion ,january #aa1 #ahff4 ,dr4 ,oppolzer1 of ,vienna1 after a careful determination of its elements1 announced the interesting fact that its orbit very nearly intersects those of the earth and ,uranus2 the perihelion being situated immediately within the former1 and the aphelion a short distance exterior to the latter4 ,the period1 according to the same astronomer1 is #cc years and #fe days4 ,the identity of this comet with that of #acff was suggested by ,professor ,h4 ,a4 ,newton soon after its appearance1--a suggestion which subsequent research has strongly corroborated4 ,it is also highly probable that the comet observed in ,china1 ,september #bi1 #aacc1 was a former return of the same body4 ,in #acff it was conspicuous to the naked eye1 while in #ahff it was wholly invisible without a telescope1--a fact indicative of its gradual dissolution4 ,the connection of this comet with the meteors of ,november #ad will be elsewhere considered4 ,,xi4 ,the ,second ,comet of #ahfg4 ,another comet of short period was discovered by ,m4 ,tempel on the #c;d of ,april1 #ahfg4 ,its orbit is the least eccentric of all known comets3 the perihelion being exterior to the orbit of ,mars2 the aphelion interior to that of ,jupiter4 ,its motion is direct1 and it completes a revolution in #e years and #h months4 ,,chapter ,,iii4 ,,comets ,,whose ,,elements ,,indicate ,,periodicity1 ,,but ,,whose ,,returns ,,have ,,not ,,been ,,recognised4 ,i4 ,the ,group whose periods are nearly equal to that of ,uranus4 ,since the commencement of the present century five comets have been discovered1 which form1 with ,halley's1 an interesting and remarkable group4 ,the first of these was detected by ,pons1 on the #bjth of ,july1 #ahab2 the second by ,olbers1 on the #fth of ,march1 #ahae2 the third by ,de ,vico1 on the #bhth of ,february1 #ahdf2 the fourth by ,brorsen1 on the #bjth of ,july1 #ahdg2 and the last by ,westphal1 on the #bgth of ,june1 #aheb4 ,the periods of these bodies are all nearly equal1 ranging from #fh to #gf years2 their eccentricities are not greatly different2 the motions of all1 except that of ,halley's1 are direct2 and the distances of their aphelia are somewhat greater than ,neptune's distance from the sun4 ,of this group1 the comets of #ahab and #ahdf seem worthy of special notice4 ,the former became visible to the naked eye shortly after its discovery1 and each continued visible about ten weeks4 ,their elements are as follows3 ,perihelion ,passage4 #ahab1 ,sept4 #ahdf1 ,mar4 #ae;d4 #g;h4 #e;d4 #ab;h4 ,long4 of ,perih'n4 #ib #ea #ij #ca ,long4 of ,a4 ,node4 #bec #cc #gg #cg ,incl4 #gc #eg #he #f ,peri'n ,dist4 #j4ggga #j4ffcg ,eccentricity4 #j4idded #j4ifbbd ,period4 #gj4fhy #gc4gae ,direction4 ,d ,d ,computer4 ,encke4 ,peirce4 ,the wonderful similarity of these elements1 except in the longitude of the ascending node1 is at once apparent4 ,it will also be noticed that the longitude of the descending node of the latter is very nearly coincident with that of the ascending node of the former4 ,these remarkable coincidences are presented to the eye in the following diagram1 where the dotted ellipse represents the orbit of the comet of #ahab1 and the continuous curve that of the comet of #ahdf4 ,illustration3 ,fig4 #c4 ,it is infinitely improbable that these coincidences should be accidental2 they point undoubtedly to a common origin of the two bodies4 ,according to the theory now generally accepted1 comets enter the solar system ab extra1 move in parabolas or hyperbolas around the sun1 and1 if undisturbed by the planets1 pass off beyond the limits of the sun's attraction1 to be seen no more4 ,if in their motion1 however1 they approach very near any of the larger planets1 their direction is changed by planetary perturbation1--their orbits being sometimes transformed into ellipses4 ,the new orbits of such bodies would pass very nearly through the points at which their greatest perturbation occurred2 and accordingly we find that the aphelia of a large proportion of the periodic comets are near the orbits of the major planets4 ,i admit1 says ,m4 ,hoek1 that the orbits of comets are by nature parabolas or hyperbolas1 and that in the cases when elliptical orbits are met with1 these are occasioned by planetary attractions1 or derive their character from the uncertainty of our observations4 ,to allow the contrary would be to admit some comets as permanent members of our planetary system1 to which they ought to have belonged since its origin1 and so to assert the simultaneous birth of that system and of these comets4 ,as for me1 ,i attribute to these a primitive wandering character4 ,traveling through space1 they move from one star to another in order to leave it again1 provided they do not meet any obstacle that may force them to remain in its vicinity4 ,such an obstacle was ,jupiter1 in the neighborhood of our sun1 for the comets of ,lexell and ,brorsen1 and probably for the greater part of periodical comets2 the other part of which may be indebted for their elliptical orbits to the attractions of ,saturn and the remaining planets4 ,generally1 then1 comets come to us from some star or other4 ,the attraction of our sun modifies their orbit1 as had been done already by each star through whose sphere of attraction they had passed4 ,we can put the question if they come as single bodies or united in systems4 ,the conclusion of this astronomer's interesting discussion is that-- ,there are systems of comets in space that are broken up by the attraction of our sun1 and whose members attain1 as isolated bodies1 the vicinity of the earth during a course of several years4#f #f ,monthly ,notices of the ,r4 ,a4 ,s41 vol4 xxv41 p4 #bdc4 ,in the researches here referred to1 it is shown by ,professor ,hoek that the comets of #ahfj ,,iii41 #ahfc ,i41 and #ahfc ,,iv4 formed a group in space previous to their entrance into our system4 ,the same fact has also been demonstrated in regard to other comets which need not here be specified4 ,now1 the comets of #ahab and #ahdf ,,iv4 have their aphelia near the orbit of ,neptune1 and hence the original parabolas in which they moved were probably transformed into ellipses by the perturbations of that planet4 ,before entering the solar domain1 they were doubtless members of a cometary system4 ,passing ,neptune near the same time1 and at some distance from each other1 their different relative positions with regard to the disturbing body may account for the slight differences in the elements of their orbits4 ,comets of the ,jovian ,group4 ,besides the eight comets enumerated in ,chapter ,,ii4 whose aphelia are in the vicinity of ,jupiter's orbit1 five others have been observed which belong apparently to the same cluster4 ,these are the comets of #aehe1 #agdc ,i41 #agff ,,ii41 #aghc1 and #ahai ,,iv4 ,the fact that these comets have not been re-observed on their successive returns through perihelion may be explained either by the difficulty of observing them1 owing to their unfavorable positions1 and to the circumstances of observers not expecting their reappearance1 their periodic character not being then suspected1 or because they may have been thrown by the disturbing action of the larger planets into orbits such as to keep them continually out of the range of view of terrestrial observers4#g #g ,dr4 ,lardner4 ,lexell's comet of #aggj is the most remarkable instance known of the change produced in the orbits of these bodies by planetary attraction4 ,this comet passed so near ,jupiter in #aggi that the attraction of the latter was #bjj times greater than that of the sun4 ,the consequence was that the comet1 whose mean distance corresponded to a period of #e-a_/b years1 was thrown into an orbit so entirely different that it has never since been visible4 ,,peters' ,,comet4 ,a telescopic comet was discovered by ,dr4 ,peters on the #bfth of ,june1 #ahdf1 which continued to be observed till the #bast of ,july4 ,its period1 according to the discoverer1 is about #ac years1 and its aphelion1 like that of ,tuttle's comet1 is in the vicinity of ,saturn's orbit4 ,it was expected to return in #ahei1 and again in #ahgb1 but each time escaped detection1 owing probably to the fact that its position was unfavorable for observation4 ,,stephan',s ,,comet 7#ahfg ,i474 ,in ,january1 #ahfg1 ,m4 ,stephan1 of ,marseilles1 discovered a new comet1 the elements of which1 after two months' observations1 were computed by ,mr4 ,g4 ,m4 ,searle1 of ,cambridge1 ,massachusetts4 ,the perihelion of this body is near the orbit of ,mars2 its aphelion near that of ,uranus1--the least distance of the orbits being about #b1jjj1jjj miles4 ,the present form of the cometary path is doubtless due to the disturbing action of ,uranus4 ,the comet completes its revolution in #cc4fb years2 consequently 7as has been pointed out by ,mr4 ,j4 ,r4 ,hind7 five of its periods are almost exactly equal to two periods of ,uranus4 ,the next approximate appulse of the two bodies will occur in #aihe1 when the form of the comet's orbit may be sensibly modified4 ,,elliptic ,,comets ,,whose ,,aphelia ,,are ,,at ,a ,,much ,,greater ,,distance ,,than ,,neptune',s ,,orbit4 ,in ,october1 #ajig1 a comet was seen both in ,europe and ,china1 which was noted for the fact of its having two distinct tails1 making with each other an angle of about #dj4 ,from a discussion of the ,chinese observations 7which extended through a longer period than the ,european71 ,laugier concluded that this body is identical with the third comet of #ahdj1 which was discovered by ,galle on the #fth of ,march4 ,if1 therefore1 it has made no intermediate return without being observed1 it must have a period of about #gdc years4 ,it is also highly probable1 from the similarity of elements1 that the comet which passed its perihelion on the #eth of ,june1 #ahde1 was a reappearance of the comet of #aeif1--the period of revolution being #bdi years4 ,the elements of the great comet of #ahdc are somewhat uncertain4 ,there is a probability1 however1 of the identity of this body with the comet of #affh4 ,this would make the period #age years4 ,the third comet of #ahfb is especially interesting from its connection with the ,august meteors4 ,its period1 according to ,dr4 ,oppolzer1 is #aba-a_/b years4 ,,the ,,great ,,comet ,,of #aheh was one of the most remarkable in the nineteenth century4 ,it was discovered on the #b;d of ,june1 by ,donati1 of ,florence1 and first became visible to the naked eye about the last of ,august4 ,the comet attained its greatest brilliancy about the #ajth of ,october1 when its distance from the earth was #ej1jjj1jjj miles4 ,the length of its tail somewhat exceeded this distance4 ,if1 therefore1 the comet had been at that time directly between the sun and the earth1 the latter must have been enveloped for a number of hours in the cometic matter4 ,the observations of this comet during a period of five months enabled astronomers to determine the elements of its orbit within small limits of error4 ,it completes a revolution1 according to ,newcomb1 in #ahed years1 in an orbit somewhat more eccentric than that of ,halley's comet4 ,it will not return before the #chth century1 and will only reach its aphelion about the year #bhjj4 ,its motion per second when nearest the sun is #cf miles2 when most remote1 only #bcd yards4 ,,chapter ,,iv4 ,,other ,,remarkable ,,comets4 ,it remains to describe some of the most remarkable comets of which we have any record1 but of which we have no means of determining with certainty whether they move in ellipses1 parabolas1 or hyperbolas4 ,in the year #dff ,b4,c41 a large comet appeared simultaneously with the famous fall of meteoric stones near gospotamos4 ,the former was supposed by the ancients to have had some agency in producing the latter phenomenon4 ,another of extraordinary magnitude appeared in the year #cgc ,b4,c4 ,this comet was so bright as to throw shadows1 and its tail extended one-third of the distance from the horizon to the zenith4 ,the years #aef1 #acf1 #acj1 and #dh1 before our era1 were also signalized by the appearance of very large comets4 ,the apparent magnitude of the first of these is said to have equaled that of the sun itself2 while its light was sufficient to diminish sensibly the darkness of the night4 ,the second is said to have filled a fourth part of the celestial hemisphere4 ,the comet of #acj ,b4,c41 sometimes called the comet of ,mithridates1 because of its appearance about the time of his birth1 is said to have rivaled the sun in splendor4 ,in ,a4,d4 #agh a large comet was visible during a period of nearly three months4 ,its nucleus had a remarkably red or fiery appearance1 and the greatest length of its tail exceeded #fj4 ,the most brilliant comets of the sixth century were probably those of #eca and #ehb4 ,the train of the latter1 as seen in the west soon after sunset1 presented the appearance of a distant conflagration4 ,great comets appeared in the years #ige1 #abfd1 and #aeef4 ,of these1 the comet of #abfd had the greatest apparent magnitude4 ,it was first seen early in ,july1 and attained its greatest brilliancy in the latter part of ,august1 when its tail was #ajj in length4 ,it disappeared on the #c;d of ,october1 about the time of the death of ,pope ,urban ,,iv41 of which event the comet1 in consequence of this coincidence1 was considered the precursor4 ,these comets1 on account of the similarity of their elements1 were believed by many astronomers to be the same1 and to have a period of about #cjj years4 ,in the case of identity1 however1 another reappearance should have occurred soon after the middle of the nineteenth century4 ,as no such return was observed1 we may conclude that the comets were not the same1 and that their periods are wholly unknown4 ,the comet discovered on the #ajth of ,november1 #afah1 was one of the largest in modern times2 its tail having attained the extraordinary length of #ajd4 ,the comet of #afeb1 so carefully observed by ,hevelius1 almost equaled the moon in apparent magnitude4 ,it shone1 however1 with a lurid1 dismal light4 ,the tail of the comet of #afhj was #ij in length4 ,this body is also remarkable for its near approach to the sun2 its least distance from the solar surface having been only #adg1jjj miles4 ,it will always be especially memorable1 however1 for having furnished ,newton the data by means of which he first showed that comets in their orbital motions are governed by the same principle that regulates the planetary revolutions4 ,of all the comets which appeared during the eighteenth century1 that which passed its perihelion on the #gth of ,october1 #agfi1 had the greatest apparent magnitude4 ,it was discovered by ,messier on the #hth of ,august1 and continued to be observed till the #ast of ,december4 ,on the #aath of ,september the length of its tail was #ig4 ,the comet discovered on the #bfth of ,march1 #ahaa1 is in some respects the most remarkable on record4 ,it was observed during a period of #af months and #bb days1--the longest period of visibility known4 ,on account of its situation with respect to the earth1 the apparent length of its tail was much less than that of some other comets2 its true length1 however1 was at one time #abj1jjj1jjj miles2 and ,sir ,william ,herschel found that on the #abth of ,october the greatest circular section of the tail was #ae1jjj1jjj miles in diameter4 ,the same astronomer found the diameter of the head of the comet to be #abg1jjj miles1 and that of the envelope at least #fdc1jjj4 ,as a general thing1 the length of a comet-train increases very rapidly as the body approaches the sun4 ,but the perihelion distance of the comet of #ahaa was considerably greater than the distance of the earth from the sun2 while its nearest approach to the earth was #aaj1jjj1jjj miles4 ,its true magnitude1 therefore1 has probably not been surpassed by any other observed2 and had its perihelion been very near the sun1 it must have exhibited an appearance of terrific grandeur4 ,this comet has an elliptic orbit1 and its period1 according to ,argelander1 is #cjfe years4 ,the great comet of #ahfa was discovered on the #acth of ,may1 by ,mr4 ,john ,tebbut1 ,jr41 of ,new ,south ,wales4 ,in this country1 as well as in ,europe1 it was first generally observed on the evening of ,june #cj1--ai days after its perihelion passage4 ,sir ,john ,herschel1 who observed it in ,kent1 ,england1 remarks that it far exceeded in brilliancy any comets he had ever seen1 not excepting those of #ahaa and #aheh4 ,according to ,father ,secchi1 of the ,collegio ,romano1 the length of its tail was #aah4 ,this1 with a single exception1#h is the greatest on record4 ,the computed orbit is elliptical2 the period1 #dai years4 #h ,the tail of the first comet of #ahfe 7observed in the ,southern ,hemisphere7 attained the unprecedented length of #aej4--,m4 ,n4 ,r4 ,a4 ,s41 vol4 xxv41 p4 #bbj4 ,,chapter ,v4 ,,the ,,position ,,and ,,arrangement ,,of ,,cometary ,,orbits4 ,the cosmical masses from which comets are derived seem to traverse in great numbers the interstellar spaces4 ,in consequence of the sun's progressive motion1 these nebulous bodies are sometimes drawn toward the centre of our system4 ,if1 in this approach1 they are not disturbed by any of the large planets1 they again recede in parabolas or hyperbolas4 ,when1 however1 as must sometimes be the case1 they pass near ,jupiter1 ,saturn1 ,uranus1 or ,neptune1 their orbits may be transformed into elongated ellipses4 ,the periodicity of many comets may thus be accounted for4 ,in the present chapter it is proposed to consider the probable consequences of the sun's motion through regions of space in which cometary matter is widely diffused2 to compare our theoretical deductions with observed phenomena2 and thus refer to their physical cause a variety of facts which have hitherto received no satisfactory explanation4#i #i ,this chapter is the substance of a paper read before the ,american ,philosophical ,society1 ,november #ai1 #ahfi4 #a4 ,as comets1 at least in many instances1 owe their periodicity to the disturbing action of the major planets1 and as this planetary influence is sometimes sufficient1 especially in the case of ,jupiter and ,saturn1 to change the direction of cometary motion1 the great majority of periodic comets should move in the same direction with the planets4 ,now1 of the comets known to be elliptical1 #gj per cent4 have direct motion4 ,in this respect1 therefore1 theory and observation are in striking harmony4 #b4 ,when the relative positions of a comet and the disturbing planet are such as to give the transformed orbit of the former a small perihelion distance1 the comet must return to the point at which it received its greatest perturbation2 in other words1 to the orbit of the planet4 ,the aphelia of the comets of short period ought therefore to be found1 for the most part1 in the vicinity of the orbits of the major planets4 ,this1 as already shown in ,chapters ,,ii4 and ,,iii41 is strikingly the case4 ,the actual distances of these aphelia1 however1 as compared with the respective distances of ,jupiter1 ,saturn1 ,uranus and ,neptune1 are presented at one view in the following tables3 ,i4 ,,comets ,,whose ,,aphelion ,,distances ,,are ,,nearly ,,equal ,,to #e4bj1 ,,the ,,radius ,,of ,,jupiter',s ,,orbit4 ,comets4 ,aph4 ,dist4 #a4 ,encke's #d4ji #b4 #ahai ,,iv #d4ha #c4 ,de ,vico's #e4jb #d4 ,pigott's 7#aghc7 #e4bh #e4 #ahfg ,,ii #e4bi #f4 #agdc ,i #e4cb #g4 #agff ,,ii #e4dg #h4 #ahai ,,iii #e4ee #i4 ,brorsen's #e4fd #aj4 ,d',arrest's #e4ge #aa4 ,faye's #e4ic #ab4 ,bicla's #f4ai ,,ii4 ,,comets ,,whose ,,aphelion ,,distances ,,are ,,nearly ,,equal ,,to #i4ed1 ,,the ,,radius ,,of ,,saturn',s ,,orbit4 ,comets4 ,aph4 ,dist4 #a4 ,peters' 7#ahdf ,,vi47 #i4de #b4 ,tuttle's 7#aheh ,i47 #aj4db ,,iii4 ,,comets ,,whose ,,aphelion ,,distances ,,are ,,nearly ,,equal ,,to #ai4ah1 ,,the ,,radius ,,of ,,uranus',s ,,orbit4 ,comets4 ,aph4 ,dist4 #a4 #ahfg ,i #ai4bh #b4 ,november meteors #ai4fe #c4 #ahff ,i #ai4ib ,,iv4 ,,comets ,,whose ,,aphelion ,,distances ,,are ,,nearly ,,equal ,,to #cj4jd1 ,,the ,,radius ,,of ,,neptune',s ,,orbit4 ,comets4 ,aph4 ,dist4 #a4 ,westphal's 7#aheb ,,iv47 #ca4ig #b4 ,pons' 7#ahab7 #cc4da #c4 ,olbers' 7#ahae7 #cd4je #d4 ,de ,vico's 7#ahdf ,,iv47 #cd4ce #e4 ,brorsen's 7#ahdg ,v47 #ce4jg #f4 ,halley's#aj #ce4cg #aj ,halley's comet in aphelio is too remote from the plane of the ecliptic to be much disturbed by ,neptune4 ,has the original position of the orbit been changed by ,jupiter's influence8 ,the coincidences here pointed out 7some of which have been noticed by others7 appear1 then1 to be necessary consequences of the motion of the solar system through spaces occupied by meteoric nebul4 ,hence the observed facts receive an obvious explanation4 ,in regard to comets of long period we have only to remark that1 for anything we know to the contrary1 there may be causes of perturbation far exterior to the orbit of ,neptune4 #c4 ,from what we observe in regard to the larger bodies of the universe--a clustering tendency being everywhere apparent1--it seems highly improbable that cometic matter should be uniformly distributed in the sidereal spaces4 ,we would expect1 on the contrary1 to find it collected in groups or clusters4 ,this view is also in remarkable harmony with the facts of observation4 ,in #aej years1 from #afjj to #agej1 #af comets were visible to the naked eye2 of which #h appeared in the #be years from #affd to #afhi4 ,again1 during #fj years1 from #agej to #ahaj1 only #e comets were visible to the naked eye1 while in the next #ej years there were double that number4 ,the probable cause of such variations is sufficiently obvious4 ,as the sun in its progressive motion approaches a cometary group1 the latter is drawn toward the centre of our system2 the nearer members with greater velocity than the more remote4 ,those of the same cluster would enter the solar domain at periods not very distant from each other2 the forms of their orbits depending upon their original relative positions with reference to the sun's course1 and also on planetary perturbations4 ,it is evident also that the passage of the solar system through a region of space comparatively destitute of cometic clusters would be indicated by a corresponding paucity of comets4 #d4 ,the line of apsides of a large proportion of comets will be approximately coincident with the solar orbit4 ,the point towards which the sun is moving is in longitude about #bfj4 ,the quadrants bisected by this point and that directly opposite extend from #bae to #cje1 and from #ce to #abe4 ,the number of cometary perihelia found in these quadrants up to ,july1 #ahfh 7periodic comets being counted but once7 was #aei1 or #fb per cent42 in the other two quadrants1 #ih1 or #ch per cent4 ,this tendency of the perihelia to crowd together in two opposite regions has been noticed by different writers4 #e4 ,comets whose positions before entering our system were very remote from the solar orbit must have overtaken the sun in its progressive motion2 hence their perihelia must fall1 for the most part1 in the vicinity of the point towards which the sun is moving2 and they must in general have very small perihelion distances4 ,now1 what are the observed facts in regard to the longitudes of the perihelia of the comets which have approached within the least distance of the sun's surface8 ,but three have had a perihelion distance less than #j4ja4 ,all these1 it will be seen by the following table1 have their perihelia in close proximity to the point referred to3 ,i4 ,,comets ,,whose ,,perihelion ,,distances ,,are ,,less ,,than #j4ja4 ,perihelion ,passage4 ,per4 ,dist4 ,long4 of ,per4 #a4 #affh1 ,feb4 #bh;d4 #ac;h4 #j4jjdg #bgg #b #b4 #afhj1 ,dec4 #ag #bc #j4jjfb #bfb #di #c4 #ahdc1 ,feb4 #bg #i #j4jjee #bgh #ci ,in ,table ,,ii4 all but the last have their perihelia in the same quadrant4 ,,ii4 ,,comets ,,whose ,,perihelion ,,distances ,,are ,,greater ,,than #j4ja ,,and ,,less ,,than #j4je4 ,perihelion ,passage4 ,per4 ,dist4 ,long4 of ,per4 #a4 #afhi1 ,nov #bi;d4 #d;h4 #j4jahi #bfi #da #b4 #ahaf1 ,march #a #h #j4jdhe #bfg #ce #c4 #ahbf1 ,nov #ah #i #j4jbfh #cae #ca #d4 #ahdg1 ,march #cj #f #j4jdbe #bgf #b #e4 #ahfe1 ,jan #ad #g #j4jbfj4 #ada #ae ,the perihelion of the first comet in ,table ,,iii4 is remote from the direction of the sun's motion2 that of the second is distant but #ad1 and of the third #ba4 ,,iii4 ,,comets ,,whose ,,perihelion ,,distances ,,are ,,greater ,,than #j4je ,,and ,,less ,,than #j4a4 ,perihelion ,passage4 ,per4 ,dist4 ,long4 of ,per4 #a4 #aeic1 ,july #ah;d4 #ac;h4 #j4jhia #agf #ai #b4 #aghj1 ,sept4 #cj #bb #j4jifc #bdf #ce #c4 #ahba1 ,march #ba #ab #j4jiah #bci #bi ,with greater perihelion distances the tendency of the perihelia to crowd together round the point indicated is less distinctly marked4 #f4 ,few comets of small perihelion distance should have their perihelia in the vicinity of longitude #hj1 the point opposite that towards which the sun is moving4 ,accordingly we find1 by examining a table of cometary elements1 that with a perihelion distance less than #j4a there is not a single perihelion between #ce and #abe2 between #j4a and #j4b but #c2 and between #j4b and #j4c only #a4 ,,chapter ,,vi4 ,,the ,,disintegration ,,of ,,comets4 ,the fact that in several instances meteoric streams move in orbits identical with those of certain comets was first established by the researches of ,signor ,schiaparelli4 ,the theory1 however1 of an intimate relationship between comets and meteors was advocated by the writer as long since as #ahfa1aa--several years previous to the publication of ,schiaparelli's memoirs4 ,in the essay here referred to it was maintained-- #aa ,danville ,quarterly ,review1 ,december1 #ahfa4 #a4 ,that meteors and meteoric rings are the dbris of ancient but now disintegrated comets whose matter has become distributed around their orbits4 #b4 ,that the separation of ,biela's comet as it approached the sun in ,december1 #ahde1 was but one in a series of similar processes which would probably continue until the individual fragments would become invisible4 #c4 ,that certain luminous meteors have entered the solar system from the interstellar spaces4#ab #ab ,others1 it was supposed1 might have originated within the system1--a view which the writer has not wholly abandoned4 #d4 ,that the orbits of some meteors and periodic comets have been transformed into ellipses by planetary perturbation2 and #e4 ,that numerous facts--some observed in ancient and some in modern times--have been decidedly indicative of cometary disintegration4 ,what was thus proposed as theory has been since confirmed as undoubted facts4 ,when the hypothesis was originally advanced1 the data required for its mathematical demonstration were entirely wanting4 ,the evidence1 however1 by which it was sustained was sufficient to give it a high degree of probability4 ,the existence of a divellent force by which comets near their perihelia have been separated into parts is clearly shown by the following facts4 ,whether this force1 as suggested by ,schiaparelli1 is simply the unequal attraction of the sun on different parts of the nebulous mass1 or whether1 in accordance with the views of other astronomers1 it is to be regarded as a cosmical force of repulsion1 is a question left for future discussion4 ,,historical ,,facts4 #a4 ,seneca informs us that ,ephoras1 a ,greek writer of the fourth century before ,christ had recorded the singular fact of a comet's separation into two distinct parts4#ac ,this statement was deemed incredible by the ,roman philosopher1 inasmuch as the occurrence was then without a parallel4 ,more recent observations of similar phenomena leave no room to question the historian's veracity4 #ac ,qust4 ,nat41 lib4 vii41 cap4 xvi4 #b4 ,the head of the great comet of ,a4,d4 #chi1 according to the writers of that period1 was composed of several small stars4 7,hind's ,comets1 p4 #ajc47 #c4 ,on ,june #bg1 ,a4,d4 #daf1 two comets appeared in the constellation ,hercules1 and pursued nearly the same apparent path4 ,probably at a former epoch the pair had constituted a single comet4#ad #ad ,chambers' ,descr4 ,astr41 p4 #cgd4 #d4 ,on ,august #d1 #hac1 a comet was seen which resembled two moons joined together4 ,they subsequently separated1 the fragments assuming different forms4#ae #ae ,ibid41 p4 #chc4 #e4 ,the ,chinese annals record the appearance of three comets--one large and two smaller ones--at the same time1 in the year #hif of our era4 ,they traveled together for three days4 ,the little ones disappeared first1 and then the large one4#af ,the bodies were probably fragments of a large comet which1 on approaching the sun1 had been separated into parts a short time previous to the date of their discovery4 #af ,ibid41 p4 #chh4 #f4 ,the third comet of #afah4--,the great comet of #afah exhibited decided symptoms of disintegration4 ,when first observed 7on ,november #cj71 its appearance was that of a lucid and nearly spherical mass4 ,on the eighth day the process of division was distinctly noticed1 and on the #bjth of ,december it resembled a cluster of small stars4#ag #ag ,hevelius1 ,cometographia1 p4 #cda4 ,see also ,grant's ,hist4 of ,phys4 ,astr41 p4 #cjb4 #g4 ,the comet of #affa4--,the elements of the comets of #aecb and #affa have a remarkable resemblance1 and previous to the year #agij astronomers regarded the bodies as identical4 ,the similarity of the elements is seen at a glance in the following table3 ,comet of #aecb4 ,comet of #affa4 ,longitude of perihelion #aaa #dh #aae #af ,longitude of ascending node #hg #bc #ha #ed ,inclination #cb #cf #cc #a ,perihelion distance #j4eaib #j4ddbg ,motion ,direct4 ,direct4 ,the elements of the former are by ,olbers2 those of the latter by ,mechain4 ,the return of the comet about #agij1 though generally expected1 was looked for in vain4 ,as a possible explanation of this fact1 it is interesting to recur to an almost forgotten statement of ,hevelius4 ,this astronomer observed in the comet of #affa an apparent breaking up of the body into separate fragments4#ah ,the case may be analogous to that of ,biela's comet4 #ah ,cometographia1 p4 #dag4 #h4 ,the identity of the comets of #ahff and #acff1 first suggested by ,professor ,h4 ,a4 ,newton1 is now unquestioned4 ,the existence then of a meteoric swarm1 moving in the same track1 is not the only evidence of the original comet's partial dissolution4 ,the comet of #ahff was invisible to the naked eye2 that of #acff1 seen under nearly similar circumstances1 was a conspicuous object4 ,the statement of the ,chinese historian that it appeared nearly as large as a tow measure1#ai though somewhat indefinite1 certainly justifies the conclusion that its magnitude has greatly diminished during the last #ejj years4 ,the meteors moving in the same orbit are doubtless the products of this gradual separation4 #ai ,williams' ,chinese ,observations of ,comets1 p4 #gc4 #i4 ,the repartition of ,biela's comet in #ahde1 as well as the non-appearance of the two fragments in #ahfe and #ahgb1bj were referred to in a previous chapter4 #bj ,one of the parts was seen at ,madras1 ,india1 on the mornings of ,december #b and #c1 #ahgb4 ,the comet of ,halley1 if we may credit the descriptions given by ancient writers1 has been decreasing in brilliancy from age to age4 ,the same is true in regard to several others believed to be periodic4 ,the comet of ,a4,d4 #ajig had a tail #ej long4 ,at its return1 in ,march1 #ahdj1 the length of its tail was only #e4 ,the third comet of #agij and the first of #ahbe are supposed1 from the similarity of their elements1 to be identical4 ,each perihelion passage occurred in ,may1 yet the tail at the former appearance was #d in length1 at the latter but #b-a_/b4 ,other instances might be specified of this apparent gradual dissolution4 ,it would seem1 indeed1 extremely improbable that the particles driven off from comets in their approach to the sun1 forming tails extending millions of miles from the principal mass1 should again be collected around the same nuclei4 ,the fact1 then1 that meteors move in the same orbits with comets is but a consequence of that disruptive process so clearly indicated by the phenomena described4 ,in this view of the subject1 comets--even such as move in elliptic orbits--are not to be regarded as permanent members of the solar system4 ,their dbris becomes gradually scattered around the orbit4 ,some parts of the nebulous ring will be more disturbed than others by planetary perturbation4 ,portions of such streams as nearly intersect the earth's path sometimes penetrate the atmosphere4 ,their rapid motion renders them luminous4 ,if very minute1 they are burnt up or dissipated without leaving any solid deposit2 we then have the phenomena of shooting-stars4 ,when1 however1 as is sometimes the case1 they contain a considerable quantity of solid matter1 they reach the earth's surface as meteoric stones4 ,,ii4 ,,meteors4 ,,chapter ,,vii4 ,,meteoric ,,stones4 ,although numerous instances of the fall of aerolites had been recorded1 some of them apparently well authenticated1 the occurrence long appeared too marvelous and improbable to gain credence with scientific men4 ,such a shower of rocky fragments occurred1 however1 on the #bfth of ,april1 #ahjc1 at ,l',aigle1 in ,france1 as forever to dissipate all doubt on the subject4 ,similar displays since that time have been frequently witnessed2--indeed scarcely a year passes without the fall of meteoric stones in some part of the earth1 either singly or in clusters4 ,it would not comport with the design of the present treatise to give an extended list of these phenomena4 ,the following account1 however1 includes the most important instances in which the fall of meteoric stones has been actually observed3 7#a47 #adgh ,b4,c4--,according to the celebrated ,parian chronicle1 an aerolite1 or thunder-stone1 as it was called1 fell in the island of ,crete1 about #adgh years before the ,christian era4 ,this is undoubtedly the most ancient stone-fall on record4 ,meteoric masses have been found1 however1 the fall of which probably occurred at an epoch still more ancient4 7#b47 #abjj ,b4,c4--,a number of stones1 which were anciently preserved in ,orchomenos1 a town of ,boeotia1 were said to have fallen from heaven about twelve centuries before our era4 7#c47 #aafh ,b4,c4--,a mass of iron1 as we learn from the ,parian chronicle1 was seen to descend upon ,mount ,ida1 in ,crete4 7#d47 #fed ,b4,c4--,according to ,livy1 a number of meteoric stones fell on the ,alban ,hill1 near ,rome1 about the year #fed ,b4,c4 7#e47 #faf ,b4,c41 ,january #ad4--;,it is related in the ,chinese annals that on the #adth of ,january1 #faf ,b4,c41 a meteoric stone-fall broke several chariots and killed ten men4 7#f47 #dff ,b4,c4--,a mass of rock1 described as of the size of two millstones1 fell at gospotamos1 in ,thrace4 ,an attempt to rediscover this meteoric mass1 so celebrated in antiquity1 was recently made1 but without success4 ,notwithstanding this failure1 ,humboldt expressed the hope that1 as such a body would be difficult to destroy1 it may yet be found1 since the region in which it fell is now become so easy of access to ,european travelers4 7#g47 #dfe ,b4,c4--,the famous stone called the ,mother of the ,gods1 and which is described or alluded to by many ancient writers1 was said to have fallen from the skies4 ,the poet ,pindar was seated on a hill at the time of its descent1 and the meteorite struck the earth near his feet4 ,the stone1 as it fell1 was encircled by fire4 ,it is said to have been of moderate dimensions1 of a black hue1 of an irregular1 angular shape1 and of a metallic aspect4 ,an oracle had predicted that the ,romans would continue to increase in prosperity if they were put in possession of this precious deposit2 and ,publius ,scipio ,nasico was accordingly deputed to ,attalus1 ,king of ,pergamus1 to obtain and receive the sacred idol1 whose worship was instituted at ,rome #bjd years before the ,christian era4--,edinburgh ,encyclopedia4 7#h47 ,a4,d4 #iba4--;,an immense aerolite fell into the river 7a branch of the ,tiber7 at ,narni1 in ,italy4 ,it projected three or four feet above the surface of the water4 7#i47 #adib1 ,november #g4--;,an aerolite1 weighing #bgf pounds1 fell at ,ensisheim1 in ,alsace1 penetrating the earth to the depth of three feet4 ,this stone1 or the greater part of it1 may still be seen at ,ensisheim4 7#aj47 #aeaa1 ,september #ad4--;,at noon an almost total darkening of the heavens occurred at ,crema4 ,during this midnight gloom1 says a writer of that period1 unheard-of thunders1 mingled with awful lightnings1 resounded through the heavens4444 ,on the plain of ,crema1 where never before was seen a stone the size of an egg1 there fell pieces of rock of enormous dimensions and of immense weight4 ,it is said that ten of these were found1 weighing #ajj pounds each4 ,a monk was struck dead at ,crema by one of these rocky fragments4 ,this terrific display is said to have lasted two hours1 and #abjj aerolites were subsequently found4 7#aa47 #afcg1 ,november #bi4--;,a stone1 weighing #ed pounds1 fell on ,mount ,vaison1 in ,provence4 7#ab47 #afej1 ,march #cj4--;,a ,franciscan monk was killed at ,milan by the fall of a meteoric stone4 7#ac47 #afgd4--,two ,swedish sailors were killed on shipboard by the fall of an aerolite4 7#ad47 #agea1 ,may #bf4--,two meteoric masses1 consisting almost wholly of iron1 fell near ,agram1 the capital of ,croatia4 ,the larger fragment1 which weighs #gb pounds1 is now in ,vienna4 7#ae47 #agij1 ,july #bd4--;,between #i and #aj o'clock at night a very large meteor was seen near ,bordeaux1 ,france4 ,over ,barbotan a loud explosion was heard1 which was followed by a shower of meteoric stones of various magnitudes4 7#af47 #agid1 ,july4--,a fall of about a dozen aerolites occurred at ,sienna1 ,tuscany4 7#ag47 #agie1 ,december #ac4--;,a large meteoric stone fell near ,wold ,cottage1 in ,yorkshire1 ,england4 ,several persons heard the report of an explosion in the air1 followed by a hissing sound2 and afterward felt a shock1 as if a heavy body had fallen to the ground at a little distance from them4 ,one of these1 a plowman1 saw a huge stone falling toward the earth1 eight or nine yards from the place where he stood4 ,it threw up the mould on every side2 and after penetrating through the soil1 lodged some inches deep in solid chalk-rock4 ,upon being raised1 the stone was found to weigh #ef pounds4 ,it fell in the afternoon of a mild1 but hazy day1 during which there was no thunder or lightning2 and the noise of the explosion was heard through a considerable district4--,milner's ,gallery of ,nature1 p4 #acd4 7#ah47 #agif1 ,february #ai4--;,a stone of #aj pounds' weight fell in ,portugal4 7#ai47 #ahjc1 ,april #bf4--,this remarkable shower was referred to on a previous page4 ,at #a o'clock ,p4,m41 the heavens being almost cloudless1 a tremendous noise1 like that of thunder1 was heard1 and at the same time an immense fire-ball was seen moving with great rapidity through the atmosphere4 ,this was followed by a violent explosion1 which lasted several minutes1 and which was heard not only at ,l',aigle1 but in every direction around it to the distance of #gj miles4 ,immediately after1 a great number of meteoric stones fell to the earth1 generally penetrating to some distance beneath the surface4 ,nearly #cjjj of these fragments were found and collected1 the largest weighing about #ag pounds4 ,the occurrence very naturally excited great attention4 ,m4 ,biot1 under the authority of the government1 repaired to the place1 collected the various facts in regard to the phenomenon1 took the testimony of witnesses1 etc41 and finally embraced the results of his investigations in an elaborate memoir4 7#bj47 #ahjg1 ,december #ad4--;,a large meteor exploded over ,weston1 ,connecticut4 ,the height1 direction1 velocity and magnitude of this body were discussed by ,dr4 ,bowditch in a memoir communicated to the ,american ,academy of ,arts and ,sciences in #ahae4 ,the appearance of the meteor occurred about #f;h4 #aem4 ,a4,m41--just after daybreak4 ,its apparent diameter was half that of the full moon2 its time of flight1 about #cj seconds4 ,within less than a minute from the time of its disappearance three distinct reports1 like those of artillery1 were heard over an area several miles in diameter4 ,each explosion was followed by the fall of meteoric stones4 ,unlike most aerolites1 these bodies when first found were so soft as to be easily pulverized between the fingers4 ,on exposure to the air1 however1 they gradually hardened4 ,the weight of the largest fragment was #ce pounds4 7#ba47 #ahei1 ,november #ae4--;,between #i and #aj o'clock in the morning an extraordinary meteor was seen in several of the ,new ,england ,states1 ,new ,york1 ,new ,jersey1 the ,district of ,columbia1 and ,virginia4 ,the apparent diameter of the head was nearly equal to that of the sun1 and it had a train1 notwithstanding the bright sunshine1 several degrees in length4 ,its disappearance on the coast of the ,atlantic was followed by a series of the most terrific explosions4 ,it is believed to have descended into the water1 probably into ,delaware ,bay4 ,a highly interesting account of this meteor1 by ,professor ,loomis1 may be found in the ,american ,journal of ,science and ,arts for ,january1 #ahfj4 7#bb47 #ahfj1 ,may #a4--;,about #bj minutes before #a o'clock1 ,p4,m41 a shower of meteoric stones fell in the southwest corner of ,guernsey county1 ,ohio4 ,full accounts of the phenomena are given in ,silliman's ,journal for ,july1 #ahfj1 and ,january and ,july1 #ahfa1 by ,professors ,e4 ,b4 ,andrews1 ,e4 ,w4 ,evans1 ,j4 ,l4 ,smith1 and ,d4 ,w4 ,johnson4 ,from these interesting papers we learn that the course of the meteor was about #dj west of north4 ,its visible track was over ,washington and ,noble counties1 and the prolongation of its projection1 on the earth's surface1 passes directly through ,new ,concord1 in the southeast corner of ,muskingum county4 ,the meteor when first seen was about #dj miles from the earth's surface4 ,the sky1 at the time1 was for the most part covered with clouds over northwestern ,ohio1 so that if any portion of the meteoric mass continued on its course it was invisible4 ,the velocity of the meteor1 in relation to the earth's surface1 was from three to four miles per second2 and hence its absolute velocity in the solar system must have been somewhat greater than that of the earth4 ,at ,new ,concord1#ba ,muskingum county1 where the meteoric stones fell1 and in the immediate neighborhood1 there were many distinct and loud reports heard4 ,at ,new ,concord there was first heard in the sky1 a little southeast of the zenith1 a loud detonation1 which was compared to that of a cannon fired at the distance of half a mile4 ,after an interval of ten seconds1 another similar report4 ,after two or three seconds another1 and so on with diminishing intervals4 ,twenty-three distinct detonations were heard1 after which the sounds became blended together and were compared to the rattling fire of an awkward squad of soldiers1 and by others to the roar of a railway train4 ,these sounds1 with their reverberations1 are thought to have continued for two minutes4 ,the last sounds seemed to come from a point in the southeast #de below the zenith4 ,the result of this cannonading was the falling of a large number of stony meteorites upon an area of about #aj miles long by #c wide4 ,the sky was cloudy1 but some of the stones were seen first as 'black specks'1 then as 'black birds'1 and finally falling to the ground4 ,a few were picked up within #bj or #cj minutes4 ,the warmest was no warmer than if it had lain on the ground exposed to the sun's rays4 ,they penetrated the earth from two to three feet4 ,the largest stone1 which weighed #ajc pounds1 struck the earth at the foot of a large oak-tree1 and1 after cutting off two roots1 one five inches in diameter1 and grazing a third root1 it descended two feet ten inches into hard clay4 ,this stone was found resting under a root that was not cut off4 ,this would seemingly imply that it entered the earth obliquely4 #ba ,new ,concord is close to the ,guernsey county line4 ,nearly all the stones fell in ,guernsey4 ,over thirty of the stones which fell were discovered1 while doubtless many1 especially of the smaller1 being deeply buried beneath the soil1 entirely escaped observation4 ,the weight of the largest ten was #dah pounds4 7#bc47 #ahfj1 ,july #ad4--;,about #b o'clock ,p4,m4 on the #adth of ,july1 #ahfj1 a shower of aerolites fell at ,dhurmsala1 in ,india4 ,the fall was attended by a tremendous detonation1 which greatly terrified the inhabitants of the district4 ,the natives1 supposing the stones to have been thrown by some of their deities from the summit of the ,himalayas1 carried off many fragments to be kept as objects of religious veneration4 ,lord ,canning and ,mr4 ,j4 ,r4 ,saunders succeeded1 however1 in obtaining numerous specimens1 which they forwarded to the ,british ,museum and several ,european cabinets4 ,they are earthy aerolites1 of a specific gravity somewhat greater than that of granite4 7#bd47 #ahfd1 ,may #ad4--;,early in the evening a very large and brilliant meteor was seen in ,france1 from ,paris to the ,spanish border4 ,at ,montauban and in the vicinity loud explosions were heard1 which were followed by showers of meteoric stones near the villages of ,orgueil and ,nohic4 ,the principal facts in regard to the meteor are the following3 ,elevation when first seen1 over #ee miles at the time of its explosion #bj ,inclination of its path to the horizon #bj or #be ,velocity per second1 about #bj miles1 or equal to that of the earth's orbital motion4 ,this example1 says ,professor ,newton1 affords the strongest proof that the detonating and stone-producing meteors are phenomena not essentially unlike4 7#be47 #ahfh1 ,january #cj4--;,it is obviously a matter of much importance that the composition and general characteristics of aerolites1 together with the phenomena attending their fall1 should be carefully noted2 as such facts have a direct bearing on the theory of their origin4 ,in this regard the memoirs of ,professors ,j4 ,g4 ,galle1 of ,breslau1 and ,g4 vom ,rath1 of ,bonn1 on a meteoric fall which occurred at ,pultusk1 ,poland1 on the #cjth of ,january1 #ahfh1 have more than ordinary interest4 ,these memoirs establish the fact that the aerolites of the ,pultusk shower entered our atmosphere as a swarm or cluster of distinct meteoric masses4 ,it is shown1 moreover1 by ,dr4 ,galle that this meteor-group had a proper motion when it entered the solar system of at least from #d-a_/b to #g miles per second4 ,the foregoing list contains but a small proportion of the meteoric stones whose fall has been actually observed4 ,but1 besides these1 other masses have been found so closely similar in structure to aerolites whose descent has been witnessed1 as to leave no doubt in regard to their origin4 ,one of these is a mass of iron and nickel1 weighing #afhj pounds1 found by the traveler ,pallas1 in #agdi1 at ,abakansk1 in ,siberia4 ,this immense aerolite may be seen in the ,imperial ,museum at ,st4 ,petersburg4 ,on the plain of ,otumpa1 in ,buenos ,ayres1 is a meteoric mass #g-a_/b feet in length1 partly buried in the ground4 ,its estimated weight is about #af tons4 ,a specimen of this stone1 weighing #adjj pounds1 has been removed and deposited in one of the rooms of the ,british ,museum4 ,a similar block1 of meteoric origin1 weighing more than six tons1 was discovered some years since in the province of ,bahia1 in ,brazil4 ,,general ,,remarks4 #a4 ,a ,committee on ,luminous ,meteors was appointed several years since by the ,british ,association for the ,advancement of ,science4 ,this committee1 consisting at present of ,james ,glaisher1 ,f4,r4,s41 ,robert ,p4 ,greg1 ,f4,r4,s41 ,alexander ,s4 ,herschel1 ,f4,r4,a4,s41 and ,charles ,brooke1 ,f4,r4,s41 report from year to year not only their own observations on aerolites1 fire-balls1 and falling stars1 but also such facts bearing upon the subject as can be derived from other sources4 ,an analysis of these reports justifies the conclusion that meteoric stone-falls1 like star-showers1 occur with greater frequency than usual on or about particular days4 ,these epochs1 established with more or less certainty1 are the following3 7a47 ,january #dth4 7b47 #afth4 7c47 #bith4 7d47 ,february #ajth4 7e47 #aeth--#ahth4 7f47 ,march #fth4 7g47 #abth4 7h47 ,april #ast4 7i47 #ajth--#adth4 7j47 ,may #hth--#ith4 7k47 #acth--#adth4 7l47 #agth--#aith4 7m47 ,june #c;d4 7n47 #ith4 7o47 #abth4 7p47 #afth4 7q47 ,july #c;d--#dth4 7r47 #adth--#agth4 7s47 ,august #eth--#gth4 7t47 #aath4 7u47 ,september #dth--#ajth4 7v47 ,october #acth4 7w47 ,november #eth4 7x47 #abth--#acth4 7y47 #bgth--#cjth4 7z47 ,december #eth4 7z47 #hth--#adth4 7z47 #bgth4 #b4 ,it is worthy of remark that no new elements have been found in meteoric stones4 ,humboldt1 in his ,cosmos1 called attention to this interesting fact4 ,i would ask1 he remarks1 why the elementary substances that compose one group of cosmical bodies1 or one planetary system1 may not in a great measure be identical8 ,why should we not adopt this view1 since we may conjecture that those planetary bodies1 like all the larger or smaller agglomerated masses revolving round the sun1 have been thrown off from the once far more expanded solar atmosphere1 and have been formed from vaporous rings describing their orbits round the central body8 #c4 ,but while aerolites contain no elements but such as are found in the earth's crust1 the manner in which these elements are combined and arranged is so peculiar that a skillful mineralogist will readily distinguish them from terrestrial substances4 #d4 ,of the eighteen or nineteen elements hitherto observed in meteoric stones1 iron is found in the greatest abundance4 ,the specific gravities vary from #a4id to #g4ija3 the former being that of the stone of ,alais2 the latter that of the meteorite of ,wayne county1 ,ohio1 described by ,professor ,j4 ,l4 ,smith in ,silliman's ,journal for ,november1 #ahfd1 p4 #che4 #e4 ,the average number of aerolitic falls in a year was estimated by ,schreibers at #gjj4 ,baron ,reichenbach1 however1 after a discussion of the data at hand1 makes the number much larger4 ,he regards the probable annual average for the entire surface of the earth as not less than #dejj4 ,this would give twelve daily falls4 ,they are of every variety as to magnitude1 from a weight of less than a single ounce to over fifteen tons4 ,the baron even suspects the meteoric origin of large masses of dolerite which all former geologists had considered native to our planet4 #f4 ,an analysis of any extensive table of meteorites and fire-balls proves that a greater number of aerolitic falls have been observed during the months of ,june and ,july1 when the earth is near its aphelion1 than in ,december and ,january1 when near its perihelion4 ,it is found1 however1 that the reverse is true in regard to bolides1 or fire-balls4 ,these facts are susceptible of an obvious explanation4 ,the fall of meteoric stones would be more likely to escape observation by night than by day1 on account of the relatively small number of observers4 ,but the days are shortest when the earth is in perihelion1 and longest when in aphelion2 the ratio of their lengths being nearly equal to that of the corresponding numbers of aerolitic falls4 ,on the other hand1 it is obvious that fire-balls1 unless very large1 would not be visible during the day4 ,the observed number will therefore be greatest when the nights are longest2 that is1 when the earth is near its perihelion4 ,this1 it will be found1 is precisely in accordance with observation4 ,,chapter ,,viii4 ,,shooting-,,stars4--,,meteors ,,of ,,november #ad4 ,although shooting-stars have doubtless been observed in all ages of the world1 it is only within the last half century that they have attracted the special attention of scientific men4 ,a few efforts had been made to determine the height of such meteors1 but the first general interest in the subject was excited by the brilliant meteoric display of ,november #ac1 #ahcc4 ,this shower of fire can never be forgotten by those who witnessed it4 ,the meteors were observed from the ,west ,indies to ,british ,america1 and from #fj to #ajj west longitude from ,greenwich4 ,as early as #aj o'clock on the evening of the #abth shooting-stars were observed with unusual frequency2 their motions being generally westward4 ,soon after midnight their numbers became so extraordinary as to attract the attention of all who happened to be in the open air4 ,the meteors1 however1 became more and more numerous till #d1 or half past #d1 o'clock2 and the fall did not entirely cease till ten minutes before sunrise4 ,from #b to #f o'clock the numbers were so great as to defy all efforts at counting them2 while their brilliancy was such that persons sleeping in rooms with uncurtained windows were aroused by their light4 ,the meteors varied in apparent magnitude from the smallest visible points to fire-balls equaling the moon in diameter4 ,occasionally one of the larger class would separate into several parts1 and in some instances a luminous train remained visible for three or four minutes4 ,no sound whatever accompanied the display4 ,it was noticed by many observers that all the meteors diverged from a point near the star ,gamma ,leonis2 in other words1 their paths if traced backward would intersect each other at a particular locality in the constellation ,leo4 ,in some parts of the country the inhabitants were completely terror-stricken by the magnificence of the display4 ,in the afternoon of the day on which the shower occurred the writer met with an illiterate farmer who1 after describing the phenomena as witnessed by himself1 remarked that the stars continued to fall till none were left1 and added1 ,i am anxious to see how the heavens will appear this evening2 ,i believe we shall see no more stars4 ,a gentleman of ,south ,carolina described the effect on the negroes of his plantation as follows3--,i was suddenly awakened by the most distressing cries that ever fell on my ears4 ,shrieks of horror and cries for mercy ,i could hear from most of the negroes of the three plantations1 amounting in all to about #fjj or #hjj4 ,while earnestly listening for the cause ,i heard a faint voice near the door1 calling my name4 ,i arose1 and1 taking my sword1 stood at the door4 ,at this moment ,i heard the same voice still beseeching me to arise1 and saying1 ',o my ,god1 the world is on fire6' ,i then opened the door1 and it is difficult to say which excited me the most1--the awfulness of the scene1 or the distressed cries of the negroes4 ,upwards of a hundred lay prostrate on the ground1--some speechless1 and some with the bitterest cries1 but with their hands raised1 imploring ,god to save the world and them4 ,the scene was truly awful2 for never did rain fall much thicker than the meteors fell towards the earth2 east1 west1 north1 and south1 it was the same4 ,at the time of this wonderful meteoric display ,captain ,hammond1 of the ship ,restitution1 had just arrived at ,salem1 ,massachusetts1 where he observed the phenomenon from midnight till daylight4 ,he recollected with astonishment that precisely one year before1 viz41 on the #acth of ,november1 #ahcb1 he had observed a similar appearance 7although the meteors were less numerous7 at ,mocha1 in ,arabia4 ,it was found1 moreover1 as a further and most remarkable coincidence1 that an extraordinary fall of meteors had been witnessed on the #abth of ,november1 #agii4 ,this was seen and described by ,andrew ,ellicott1 ,esq41 who was then at sea near ,cape ,florida4 ,it was also observed by ,humboldt and ,bonpland1 in ,cumana1 ,south ,america4 ,baron ,humboldt's description of the shower is as follows3--,from half after two1 the most extraordinary luminous meteors were seen toward the east4 ,thousands of bolides and falling stars succeeded each other during four hours4 ,they filled a space in the sky extending from the true east #cj toward the north and south4 ,in an amplitude of #fj the meteors were seen to rise above the horizon at ,e4,n4,e4 and at ,e41 describe arcs more or less extended1 and fall toward the south1 after having followed the direction of the meridian4 ,some of them attained a height of #dj1 and all exceeded #be or #cj4 ,mr4 ,bonpland relates1 that from the beginning of the phenomenon there was not a space in the firmament equal in extent to three diameters of the moon1 that was not filled at every instant with bolides and falling stars4 ,the ,guaiqueries in the ,indian suburb came out and asserted that the firework had begun at one o'clock4 ,the phenomenon ceased by degrees after four o'clock1 and the bolides and falling stars became less frequent2 but we still distinguished some toward the northeast a quarter of an hour after sunrise4 ,this wonderful correspondence of dates excited a very lively interest throughout the scientific world4 ,it was inferred that a recurrence of the phenomenon might be expected1 and accordingly arrangements were made for systematic observations on the #abth1 #acth1 and #adth of ,november4 ,the periodicity of the shower was thus1 in a very short time1 placed wholly beyond question4 ,the facts in regard to the phenomena of ,november #ac1 #ahcc1 were collected and discussed by ,olmsted1 ,twining1 and other astronomers4 ,the inquiry1 however1 very naturally arose whether any trace of the same meteoric group could be found in ancient times4 ,to determine this question many old historical records were ransacked by the indefatigable scientist1 ,edward ,c4 ,herrick1 in our own country1 and by ,arago1 ,quetelet1 and others1 in ,europe4 ,these examinations led to the discovery of ten undoubted returns of the ,november shower previous to that of #agii4 ,the descriptions of these former meteoric falls are given by ,professor ,h4 ,a4 ,newton in the ,american ,journal of ,science1 for ,may1 #ahfd4 ,they occurred in the years #ijb1 #ica1 #icd1 #ajjb1 #aaja1 #abjb1 #acff1 #aecc1 #afjb1 and #afih4 ,historians represent the meteors of ,a4,d4 #ijb as innumerable1 and as moving like rain in all directions4 ,the exhibition of #abjb was scarcely less magnificent4 ,on the last day of ,muharrem1 says a writer of that period1 stars shot hither and thither in the heavens1 eastward and westward1 and flew against one another like a scattering swarm of locusts1 to the right and left2 this phenomenon lasted until daybreak2 people were thrown into consternation1 and cried to ,god the ,most ,high with confused clamor4 ,the shower of #acff is thus described in a ,portuguese chronicle1 quoted by ,humboldt3 ,in the year #acff1 twenty-two days of the month of ,october being past1 three months before the death of the king1 ,don ,pedro 7of ,portugal71 there was in the heavens a movement of stars such as men never before saw or heard of4 ,at midnight1 and for some time after1 all the stars moved from the east to the west2 and after being collected together1 they began to move1 some in one direction and others in another4 ,and afterward they fell from the sky in such numbers1 and so thickly together1 that as they descended low in the air they seemed large and fiery1 and the sky and the air seemed to be in flames1 and even the earth appeared as if ready to take fire4 ,that portion of the sky where there were no stars seemed to be divided into many parts1 and this lasted for a long time4 ,the ,showers of #ahff-i4 ,the fact that all great displays of the ,november meteors have taken place at intervals of #cc or #cd years1 or some multiple of that period1 had led to a general expectation of a brilliant shower in #ahff4 ,in this country1 however1 the public curiosity was much disappointed4#bb ,the numbers seen were greater than on ordinary nights1 but not such as would have attracted any special attention4 ,the greatest number recorded at any one station was seen at ,new ,haven by ,professor ,newton4 ,on the night of the #abth #fid were counted in five hours and twenty minutes1 and on the following night1 #hha in five hours4 ,a more brilliant display was1 however1 witnessed in ,europe4 ,meteors began to appear in unusual frequency about #aa o'clock on the night of the #acth1 and their numbers continued to increase with great rapidity for more than two hours2 the maximum being reached a little after #a o'clock4 ,a writer in ,edinburgh1 ,scotland1 thus describes the phenomenon as observed at that city3--,standing on the ,calton ,hill1 and looking westward1--with the observatory shutting out the lights of ,princes ,street1--it was easy for the eye to delude the imagination into fancying some distant enemy bombarding ,edinburgh ,castle from long range2 and the occasional cessation of the shower for a few seconds1 only to break out again with more numerous and more brilliant drops of fire1 served to countenance this fancy4 ,again1 turning eastward1 it was possible now and then to catch broken glimpses of the train of one of the meteors through the grim dark pillars of that ruin of most successful manufacture1 the ,national ,monument2 and in fact from no point in or out of the city was it possible to watch the strange rain of stars1 pervading as it did all points of the heavens1 without pleased interest and a kindling of the imagination1 and often a touch of deeper feeling that bordered on awe4 ,at ,london about #a o'clock a single observer counted #bjj in two minutes4 ,the whole number seen at ,greenwich was #hdhe4 ,the shower was also observed in different countries on the continent4 #bb ,the first indication of the approaching shower was the appearance of meteors in unusual numbers at ,malta1 on the #acth of ,november1 #ahfd4 ,in #ahfe1 as observed at ,greenwich and other stations1 they were still more numerous4 ,in #ahfg the display was generally observed throughout the ,united ,states4 ,from the able and interesting reports of ,commodore ,sands and ,professors ,newcomb1 ,harkness1 and ,eastman1 we derive the following facts in regard to the shower as seen at ,washington1 ,d4 ,c43 ,commencement #a;h4 #jm4 ,a4,m4 ,nov4 #ad4 ,maximum #d #bj ,end #e #j ,number of meteors per hour at maximum #cjjj ,mean height on first appearance #ge miles4 on disappearance #ee ,position of radiant1 ,r4 ,a4 #aea1 ,decl4 #bb-a_/b4 ,the shower of #ahfh was in some respects quite remarkable1 though the number of meteors was less than in #ahff or #ahfg4 ,at ,new ,haven the fall commenced about midnight1 and from #b o'clock till daybreak over #ejjj meteors were counted4 ,the time of maximum could not be accurately determined1 as no decrease in the numbers was observable till dawn4 ,the display was also witnessed in ,england and in ,cape ,colony1 ,south ,africa4 ,the times of maxima in these countries differed so materially as to indicate a decided stratification of the meteoric stream4 ,the entire depth1 moreover1 where crossed by the earth in #ahfh1 was much greater than at the part traversed either in #ahff or #ahfg4 ,in #ahfi the shower was observed at ,port ,sad1 ,lower ,egypt1 by ,g4 ,l4 ,tupman1 ,esq42 in ,florida1 ,u4 ,s41 by ,commander ,william ,gibson1 ,u4,s4,n42 and at ,santa ,barbara1 ,california1 by ,mr4 ,g4 ,davidson and ,mrs4 ,e4 ,davidson4 ,the first observed #aab meteors in #a;h4 #edm41 from #b;h4 #cjm4 to #d;h4 #bdm41 ,alexandria mean time2 the numbers during this interval being nearly equal1 though slightly decreasing4 ,throughout the morning 7,november #ad7 the sky was only partly clear4 ,the two observers at ,santa ,barbara saw #eef in #b;h4 #bem41 ending at #c;h4 #dcm4 ,a4,m4 ,in ,florida also the display was quite brilliant1 though inferior to that of #ahfh4 ,it should be remarked that the morning in many parts of the ,united ,states was cloudy4 ,no considerable number of the meteors of this stream has been observed in any part of the world since #ahfi4 ,,discussion ,,of ,,the ,,phenomena4 ,since the memorable display of ,november #ac1 #ahcc1 the phenomena of shooting-stars have been observed and discussed with a very lively interest4 ,among the first laborers in this department of research the names of ,olmsted1 ,herrick1 and ,twining must ever hold a conspicuous place4 ,the fact that the position of the radiant point did not change with the earth's rotation at once placed the cosmical origin of the meteors wholly beyond question4 ,the theory of a ring of nebulous matter revolving round the sun in an elliptic orbit--a theory somewhat different from that proposed by ,olmsted--was found to afford a simple and satisfactory explanation of the phenomena4 ,this hypothesis of an eccentric stream of meteors intersecting the earth's orbit was adopted by ,humboldt1 ,arago1 and others1 shortly after the occurrence of the meteoric shower of #ahcc4 ,a few years previous to the display of #ahff it was shown by ,professor ,newton1 of ,yale ,college1 that the distribution of meteoric matter around the ring or orbit is far from uniform2 that the motion is retrograde2 that the node of the orbit has an annual forward motion of #ajb4f with respect to the equinox1 or of #eb4d with respect to the fixed stars2 that the periodic time must be limited to five accurately determined periods1 viz43 #ahj4je days1 #ahe4ed days1 #ced4fb days1 #cgf4e days1 or #cc4be years2 and that the inclination of the orbit to the ecliptic is about #ag4 ,professor ,newton1 for reasons assigned1 regarded the third period named as the most probable4 ,he remarked1 however1 that by computing the secular motion of the node for each periodic time1 and comparing the result with the known precession1 it was possible to determine which of the five periods is the correct one4 ,for the application of this crucial test1--a problem of more than ordinary interest1--we are indebted to ,professor ,j4 ,c4 ,adams1 of ,cambridge1 ,england4 ,by an elegant analysis it was first shown that for either of the first four periods designated by ,professor ,newton1 the annual motion of the node1 resulting from planetary perturbation1 would be considerably less than one half of the observed motion4 ,it only remained1 therefore1 to examine whether the period of #cc-a_/d years would give a motion of the node corresponding with observation4 ,professor ,adams found that in this time the longitude of the node is increased #bj by the action of ,jupiter1 #g by the action of ,saturn1 and #a by that of ,uranus4 ,the effect of the other planets is scarcely perceptible4 ,the calculated motion in #cc-a_/d years is therefore #bh4 ,the observed motion in the same time1 according to ,professor ,newton1 as previously stated1 is #bi4 ,this remarkable accordance was at once accepted by astronomers as satisfactory evidence that the period is about #cc4be years4 ,having determined the periodic time1 the mean distance1 or semi-axis major1 is found by ,kepler's third law to be #aj4cd4 ,the aphelion is consequently situated at a comparatively short distance beyond the orbit of ,uranus4 ,the orbit is represented in ,fig4 #d4 ,illustration3 ,fig4 #d4 ,it was stated at the close of ,chapter ,,vi4 that shooting-stars are the dissevered fragments of cometic matter1 which1 penetrating our atmosphere1 are rendered luminous by the resistance so encountered4 ,the discovery that comets and meteors are actually moving in the same orbits was first announced by ,signor ,schiaparelli in #ahfg4 ,the coincidence of the orbits of ,tempel's comet#bc as computed by ,dr4 ,oppolzer1 and the meteors of ,november #ad as determined by ,schiaparelli1 is too close to be regarded as merely accidental4 ,these elements are as follows3 ,nov4 ,meteors4 ,tempel's ,comet4 ,perihelion passage ,nov4 #aj4jib1 #ahff4 ,jan4 #aa4afj1 #ahff4 ,passage of descending node ,nov4 #ac4egf1 ,longitude of perihelion #ef #bf #fj #bh ,longitude of ascending node #bca #bh #bca #bf ,inclination #ag #dd #ag #ah ,perihelion distance #j4ihgc #j4igfe ,eccentricity #j4ijdf #j4ijed ,semi-major axis #aj4cdjj #aj4cbdj ,periodic time #cc4bejj y4 #cc4agfj y4 ,motion ,retrograde4 ,retrograde4 #bc ,see page #cj4 ,the fact is thus obvious that the meteors of ,november #ad are the products of the comet's gradual dissolution4 ,it has been stated that the comets of #acff and #ahff are probably identical4 ,the interval indicates a period of #cc4bhc years--greater by #ci days than that found by ,oppolzer4 ,with this value of the periodic time and the known secular variation of the node it is found that the comet and ,uranus were in close proximity about the beginning of the year #edg ,b4,c4 ,it is therefore not improbable that the former was then thrown into its present orbit by the attraction of the latter4 ,the celebrated ,leverrier designated the year #abf of our era as the probable epoch of the comet's entrance into our system4 ,this date1 however1 is incompatible with the period here adopted4 ,it is worthy of remark1 moreover1 as bearing on this question1 that the extension of the cluster in the tenth century1 as indicated by the showers of #ijb1 #ica1 and #icd1 was too great to have been effected in so short a period as #hjj years4 ,with the period of #cc4bhc years it is easy to find that the comet will make a near approach to the earth about the #afth or #agth of ,november1 #aife1 and to ,uranus in #aihc4 ,at one of these epochs the cometary orbit will probably undergo considerable transformation4 ,we have seen that the comet of #ahff1 and also the meteoroids following in its path1 have their perihelion at the orbit of the earth1 and their aphelion at the orbit of ,uranus4 ,both planets1 therefore1 at each encounter with the current not only appropriate a portion of the meteoric matter1 but entirely change the orbits of many meteoroids4 ,in regard to the devastation produced by the earth in passing through the cluster1 it is sufficient to state that1 according to ,weiss1 the meteor orbits resulting from the disturbance will have all possible periods from #ba months to #cij years4 ,it may be regarded1 therefore1 as evidence of the recent#bd introduction of this meteor-stream into the solar system that the comet of #ahff1 which constitutes a part of the cluster1 has not been deflected from the meteoric orbit by either the earth or ,uranus4 #bd ,recent in comparison with the origin of the ,august meteors1 which constitute a continuous ring4 ,,chapter ,,ix4 ,,other ,,meteoric ,,streams4 ,the ,meteors of ,august #g-aa4--,muschenbroek1 in his ,introduction to ,natural ,philosophy1 published in #agfb1 stated as the result of his own observations that shooting-stars are more abundant in ,august than in any other part of the year4 ,the fact1 however1 that a maximum occurs on the #ith or #ajth of the month was first shown by ,quetelet in #ahce4 ,since that time the shower has been regularly observed both in ,europe and ,america2 the number of meteors at the maximum sometimes amounting to #afj per hour4 ,their tracks when produced backward intersect each other at a particular point in the constellation ,perseus4 ,of the #cae meteoric displays given in ,quetelet's catalogue1 #fc belong to the ,august epoch4 ,their dates up to the commencement of the present century are as follows3 #a4 ,a4,d4 #haa1 ,july #beth4 #b4 #hbj1 #beth-#cjth4 #c4 #hbd1 #bfth-#bhth4 #d4 #hcj1 #bfth4 #e4 #hcc1 #bgth4 #f4 #hce1 #bfth4 #g4 #hda1 #beth-#cjth4 #h4 #ibd1 #bgth-#cjth4 #i4 #ibe1 #bgth-#cjth4 #aj4 #ibf1 #bgth-#cjth4 #aa4 #icc1 #beth-#cjth4 #ab4 #abdc1 ,aug4 #b;d4 #ac4 #adea1 #gth4 #ad4 #agji1 #hth4 #ae4 #aggi1 #ith-#ajth4 #af4 #agha1 #hth4 #ag4 #aghd1 #fth-#ith4 #ah4 #aghi1 #ajth4 #ai4 #agih1 #ith4 #bj4 #agii1 #ith-#ajth4 #ba4 #ahjj1 #ajth4 ,as the earth is about five days in crossing the ring1 its breadth in some parts cannot be less than #h1jjj1jjj miles4 ,in #ahff ,professor ,schiaparelli1 on computing the orbit of this meteoric stream1 noticed the remarkable agreement of its elements with those of ,swift's or ,tuttle's comet#be 7#ahfb1 ,,iii471 as computed by ,dr4 ,oppolzer4 ,these coincidences are exhibited in the following table3 ,meteors of ,comet ,,iii4 ,august #aj4 of #ahfb4 ,longitude of perihelion #cdc #ch #cdd #da ,ascending node #ach #af #acg #bg ,inclination #fc #c #ff #be ,perihelion distance #j4ifdc #j4ifbf4 ,period #aje years 787 #aba4e years4 ,motion ,retrograde4 ,retrograde4 #be ,mr4 ,swift1 of ,marathon1 ,n4 ,y41 had two or three days priority in the discovery of this comet1 but unfortunately delayed his announcement of the fact4 ,it appears1 therefore1 that the third comet of #ahfb is a part of the meteoric stream whose orbit is crossed by the earth on the #ajth of ,august4 ,the characteristics of different meteor-zones afford interesting indications in regard to their relative age1 the magnitude and composition of their corpuscles1 etc4 ,thus1 if we compare the streams of ,august #aj and ,november #ad1 we shall find that the former probably entered our system at a comparatively remote epoch4 ,we have seen that at each return to perihelion the meteoric cluster is extended over a greater arc of its orbit4 ,now1 ,tuttle's comet and the ,august meteors undoubtedly constituted a single group previous to their entering the solar domain4 ,it is evident1 however1 from the annual return of the shower during the last #ij years1 that the ring is at present nearly if not quite continuous4 ,that the meteoric mass had completed many revolutions before the ninth century of our era is manifest from the frequent showers observed between the years #haa and #hda4 ,at the same time1 the long interval of #hc years between the last observed display in the ninth century1 and the first in the tenth1 seems to indicate the existence of a wide chasm in the ring no more than a thousand years since4 ,neither the period of the meteors nor that of the comet can yet be regarded as accurately ascertained4 ,the latter1 however1 in all probability1 exceeds the former by several years4 ,now1 at each passage of the earth through the elliptic stream1 those meteoroids nearest the disturbing body must be thrown into orbits differing more or less from that of the primitive group4 ,in like manner the near approach of the comet to the earth at an ancient epoch may account for the lengthening of its periodic time4 ,the ,meteors of ,november #bg4 ,professor ,schiaparelli's brilliant discovery of the relation between comets and meteors may now be ranked with the established truths of astronomy4 ,his hypothesis1 however1 in regard to the origin of meteoric streams has not been generally accepted4 ,comets and meteors1 according to his theory1 are derived from cosmical clouds existing in great numbers in stellar space4 ,these nebul1 in consequence of their own motion or that of the sun1 are drawn towards the centre of our system4 ,by the unequal influence of the sun's attraction on different parts1 such clouds are transformed into currents of great length before reaching the limits of the planetary system4 ,shooting-stars1 fire-balls1 aerolites1 and comets being all of the same nature1 differing merely in size1 sometimes fall towards the sun as parts of the same current4 ,the views of ,dr4 ,weiss1 of ,vienna1 differ from those of ,schiaparelli1 in that he regards comets as the original bodies by whose disintegration meteor-streams are gradually formed4#bf ,cosmical clouds1 he remarks1 undoubtedly appear in the universe1 but only of such density that in most cases they possess sufficient coherence to withstand the destructive operation of the sun's attraction1 not only up to the boundaries of our solar system1 but even within it4 ,such cosmical clouds will always appear to us as comets when they pass near enough to the earth to become visible4 ,approaching the sun1 the comet undergoes great physical changes1 which finally affect the stability of its structure3 it can no longer hold together3 parts of it take independent orbits around the sun1 having great resemblance to the orbit of the parent comet4 ,with periodical comets1 this process is repeated at each successive approach to the sun4 ,gradually the products of disintegration are distributed along the comet's orbit1 and if the earth's orbit cuts this1 the phenomenon of shooting-stars is produced4 #bf ,astr4 ,nach41 ,nos4 #agaj1 #agaa4 ,for a fuller statement of ,schiaparelli's theory1 see ,silliman's ,journal for ,may1 #ahfg4 ,these views of the distinguished astronomer of ,vienna are confirmed by the star-shower of ,november #bg1 #ahgb4 ,that the orbits of the earth and ,biela's comet intersect at the point passed by the former about the last of ,november1 and that in #ahde the comet separated into two visible parts1 has been stated in a previous chapter4 ,the comet's non-appearance in ,december1 #ahfe1 and in ,september1 #ahgb1 was regarded by astronomers as presumptive evidence of its progressive dissolution4 ,a meteoric shower1 resulting from the earth's collision with the cometary dbris1 was accordingly expected about the #bgth of ,november4 ,the first indication of the approaching display appeared on the evening of ,november #bd1 when meteors in unusual numbers were observed by ,professor ,newton1 at ,new ,haven1 ,connecticut4 ,on ,wednesday evening1 the #bgth1 from the close of twilight till #h o'clock1 a decided shower of shooting-stars was noticed in various parts of the ,united ,states4 ,at ,greencastle1 ,indiana1 ,professor ,joseph ,tingley counted #aaj meteors in #dj minutes1 and at ,princeton1 in the same ,state1 ,mr4 ,d4 ,eckley ,hunter counted #gj in #hj minutes4 ,the numbers seen at ,new ,haven were considerably greater4 ,the fact that the display commenced before daylight had entirely closed seemed to indicate that only the termination of the shower had been observed in this country4 ,accordingly the display was soon found to have been witnessed from #fj ,e4 to #ij ,w4 of ,greenwich1 or through #aej of longitude4 ,in ,england the first bolide of the swarm was seen by ,m4 ,m4 ,brinkley1 at #c o'clock1 ,p4,m41 in full daylight4 ,the meteors were most numerous in the southern part of the continent1 particularly in ,italy4 ,at the ,observatory of ,breslau1 according to ,m4 ,faye1 #cjjj were seen from #f;h4 #cjm4 to #g;h4 #ejm4 ,dr4 ,heis reported that at ,mnster #bejj per hour were counted by two observers4 ,at ,naples1 ,signor ,gasparis observed two meteors per second4 ,at ,turin1 ,m4 ,denza1 ,director of the ,observatory1 reported #cc1djj in #f;h4 #cjm42 many of various and delicate colors1 and followed by long and brilliant trains4 ,at some points the numbers were so great that an accurate enumeration was wholly impossible4 ,in short1 the display was decidedly the most brilliant that has occurred since that of ,november #ac1 #ahcc4 ,but some of the most interesting circumstances in connection with the phenomena of ,november #bg1 #ahgb1 remain to be detailed4 ,astronomers without exception regarded the display as due to the earth's passage through the dbris following in the path of ,biela's comet4 ,in accordance with this view ,dr4 ,klinkerfues1 of ,gottingen1 concluded that the comet itself1 or rather its largest portion1 ought to be found in the region of the heavens nearly opposite to that from which the meteoroids appeared to radiate4#bg ,as this point in the southern hemisphere could not be observed in ,europe1 he conceived the happy idea of detecting the fugitive by means of the electric telegraph4 ,the following was accordingly dispatched to ,mr4 ,pogson1 ,director of the ,government ,observatory at ,madras1 in ,southern ,india3 ,biela touched earth on #bgth2 search near ,theta ,centauri4 ,the first two mornings after the receipt of this dispatch were cloudy at ,madras4 ,on the third1 however1 the cometary fragment was found1 and its motion accurately measured4 ,the observer described it as circular and rather bright1 with no traces of a tail4 ,but one fragment could be detected4 ,on the next morning1 ,december #c1 the comet was again observed4 ,its diameter had sensibly increased2 it had a bright nucleus1 and still presented a circular aspect4 ,a faint tail was also noticed1 equal in length to one-fourth of the moon's apparent diameter4 ,the following mornings being again cloudy1 no further observations could be obtained4 ,this cometary mass will be in close proximity to the earth about the last of ,november1 #ahib4 ,another brilliant meteoric shower may therefore be expected at that epoch4 #bg ,the radiant of the ,biela meteors is near ,gamma ,andromed4 ,the ,meteors of ,april #bj4 ,meteoric showers have occurred about the #bjth of ,april in the following years3 ,b4,c4 #fhg #ae ,a4,d4 #ehb #ajic #ajid #ajie #ajif #aabb #aabc #ahjc ,the probability that these meteors are derived from a ring which intersects the earth's orbit1 was first suggested by ,arago in #ahcf4 ,a comparison of dates led ,herrick to designate #bg years as the probable period of the cluster4 ,in the ,astronomische ,nachrichten1 ,no4 #afcb1 ,dr4 ,weiss called attention to the fact that the orbit of the first comet of #ahfa very nearly intersects that of the earth1 in longitude #baj--the point passed by the latter at the epoch of the ,april meteoric shower4 ,a relation between the meteors and the comet1 indicating an approximate equality of periods1 was thus suggested as probable4 ,but the comet1 according to ,oppolzer1 does not complete a revolution in less than #dae years4 ,if1 therefore1 the meteoric period is nearly the same1 the known dates of star-showers indicate a diffusion of meteoroids around one half of the orbit previous to the display of the year #ae ,b4,c4 ,no subsequent perturbation1 then1 of a particular part could sensibly effect the general orbit of the stream4 ,the infrequency of the display renders1 therefore1 the hypothesis of a long period extremely improbable4 ,the entire interval between #fhg ,b4,c4 and ,a4,d4 #ahjc is #bdij years1 or #ib periods of #bg4jfeb years2 and the known dates are all satisfied by the following scheme3 ,b4,c4 #fhg to ,b4,c4 #ae 44 #fgb years #be periods of #bf4hhjj y4 each4 #ae to ,a4,d4 #ehb 44 #eig #bb #bg4acfc ,a4,d4 #ehb to #ajie 44 #eac #ai #bg4jjjj #ajie to #aabb 44 #bg #a #bg4jjjj #aabb to #ahjc 44 #fha #be #bg4bdjj ,with a period of #bg years1 the perihelion being interior to the earth's orbit1 the aphelion distance of the meteors would be very nearly equal to the distance of ,uranus4 ,the next shower1 if the assumed period be correct1 ought to occur about #ahhd4 ,it is worthy of remark that near the time of the last 7hypothetical7 return ,mr4 ,du ,chaillu witnessed the meteors of this epoch1 in considerable numbers1 in the interior of ,africa4 ,the ,meteors of ,december #ab4 ,meteoric showers have occurred about the #abth of ,december in the following years3 #a4 ,a4,d4 #ija4 ,the whole hemisphere was filled with those meteors called falling-stars from midnight till morning1 to the great surprise of the beholders in ,egypt4 #b4 ,in #icj a remarkable shower of falling stars was observed in ,china4 #c4 ,extraordinary meteoric phenomena were observed at ,zurich at the same epoch in #aega4 #d4 ,on the night of the #aath and #abth of ,december1 #ahcc1 a great number of shooting-stars were seen at ,parma4 ,at the maximum as many as ten were visible at the same time4 #e4 7,doubtful47 #ahfa1 #ahfb1 and #ahfc4 ,maximum probably in #ahfb4 ,the meteors at this return were far from being comparable in numbers with the ancient displays4 ,the shower1 however1 was distinctly observed4 ,r4 ,p4 ,greg1 ,esq41 of ,manchester1 ,england1 says the period of ,december #ab1 #ahfb1 was exceedingly well defined4 ,these dates indicate a period of about #bi-a_/h years4 ,thus3 #ija to #icj #a period of #bi4jjj years4 #icj to #aega #bb periods of #bi4acf #aega to #ahcc #i periods of #bi4aaa #ahcc to #ahfb #a period of #bi4jjj ,meteors of ,october #af-bj4 ,meteoric showers were observed from the #afth to the #bjth of ,october in the years #bhh1 #adcf1 #adci1 #agdc1 and #agih4 ,these dates render it somewhat probable that the period is about #bg-a_/b years4 ,thus3 ,a4,d4 #bhh to #adci #db periods of #bg4dje years each4 #adci to #agdc #aa #bg4fcf #agdc to #agih #b #bg4ejj ,if these periods are correct1 it is a remarkable coincidence that the aphelion distances of the meteoric rings of ,april #bj1 ,october #ah1 ,november #ad1 and ,december #ab1 as well as those of the comets #ahff ,i41 and #ahfg ,i41 are all nearly equal to the mean distance of ,uranus4 ,the ,meteors of ,april #cj1 ,may #a4 ,professor ,schiaparelli1 in his list of meteoric showers whose radiant points are derived from observations made in ,italy during the years #ahfh1 #ahfi1 and #ahgj1 describes one as occurring on ,april #cj and ,may #a2 the radiant being in the ,northern ,crown4 ,the same shower has also been recognized by ,r4 ,p4 ,greg1 ,f4,r4,s41 of ,manchester1 ,england4 ,this meteor-stream1 it is now proposed to show1 is probably derived from one much more conspicuous in ancient times4 ,in ,quetelet's ,physique du ,globe we find meteoric displays of the following dates4 ,in each case the corresponding day for #ahgj is also given1#bh in order to exhibit the close agreement of the epochs3 #a4 ,a4,d4 #dja1 ,april #ith2 corresponding to ,april #bith1 for #ahgj4 #b4 #ech1 #fth2 ,april #beth1 #c4 #hci1 #agth2 ,may #ast1 #d4 #ibg1 #agth2 ,april #cjth1 #e4 #icd1 #ahth2 ,may #ast1 #f4 #ajji1 #afth2 ,april #bhth1 #bh ,making proper allowance for the precession of the equinoxes4 ,the epochs of #ibg and #icd suggest as probable the short period of #g years4 ,it is found accordingly that the entire interval of #fjh years--from #dja to #ajji--;is equal to #hi mean periods of #f4hcae years each4 ,with this approximate value the six dates are all represented as follows3 ,from ,a4,d4 #dja to ,a4,d4 #ech1 #bj periods of #f4he years4 #ech to #hci1 #dd #f4hd #hci to #ibg1 #ac #f4gg #ibg to #icd1 #a #g4jj #icd to #ajji1 #aa #f4hb ,this period nearly corresponds to those of several comets whose aphelion distances are somewhat greater than the mean distance of ,jupiter4 ,so long as the cluster occupied but a small arc of the orbit the displays would evidently be separated by considerable intervals4 ,the comparative paucity of meteors in modern times may be explained by the fact that the ring has been subject to frequent perturbations by ,jupiter4 ,groups in which the ,meteoroids are sparsely scattered4 ,by the labors of ,heis1 ,greg1 ,herschel1 ,schiaparelli1 and others1 the radiants of more than fifty sparsely strewn meteor-systems have been determined4 ,of these the following1 which are well defined1 seem worthy of special study3 ,,date4 ,,position ,,of ,,radiant4 ,r4 ,a4 ,n4 ,decl4 ,january #a-d #bcd #ea ,january #ah #bcb #cf ,april #be #adb #ec ,the orbits and periods1 except in the few cases previously considered1 are entirely unknown4 ,some of the observed clusters are probably the dbris of ancient comets whose aphelia were in the vicinity of ,jupiter's orbit4 ,,chapter ,x4 ,,the ,,origin ,,of ,,comets ,,and ,,meteors4 ,the fact that comets and meteors1 or at least a large proportion of such bodies1 have entered the solar system from stellar space1 is now admitted by all astronomers4 ,the question1 however1 in regard to the origin and nature of these cosmical clouds still remains undecided4 ,the theory that they consist of matter expelled with great velocity from the fixed stars appears to harmonize the greatest number of facts1 and is accordingly entitled to respectful consideration4 ,the evidence by which it is sustained may be briefly stated as follows3 #a4 ,the observations of ,zollner1 ,respighi1 and others1 have indicated the operation of stupendous eruptive forces beneath the solar surface4 ,the rose-colored prominences1 which ,janssen and ,lockyer have shown to be masses of incandescent hydrogen1 are regarded by ,professor ,respighi as phenomena of eruption4 ,they are the seat of movements of which no terrestrial phenomenon can afford any idea2 masses of matter1 the volume of which is many hundred times greater than that of the earth1 completely changing their position and form in the space of a few minutes4 ,the nature of this eruptive force is not understood4 ,we may assume1 however1 that it was in active operation long before the sun had contracted to its present dimensions4 #b4 ,with an initial velocity of projection equal to #chj miles per second1 the matter thrown off from the sun would be carried beyond the limits of the solar system1 never to return4 ,with velocities somewhat less1 it would be transported to distances corresponding to those of the aphelia of the periodic comets4 #c4 ,on the #gth of ,september1 #ahga1 ,professor ,young1 of ,dartmouth ,college1#bi witnessed an extraordinary explosion on the sun's surface4 ,the observer1 with his telescope1 followed the expelled matter to an elevation of over #bjj1jjj miles4 ,the mean velocity between the altitudes of #ajj1jjj and #bjj1jjj miles was #aff miles per second4 ,this rate of motion in vacuo would indicate an initial velocity of about #bfj miles per second4 ,but the sun is surrounded by an extensive atmosphere1 whose resistance must have greatly retarded the velocity of the outrush before reaching the height of #ajj1jjj miles4 ,the original velocity of these hydrogen clouds was therefore sufficient1 in all probability1 to have carried them1 if unresisted1 beyond the solar domain4 ,solid or dense matter propelled with equal force would doubtless have been driven off never to return4#cj #bi ,boston ,journal of ,chemistry1 ,november1 #ahga4 #cj ,see ,mr4 ,proctor's interesting discussion of this subject in the ,monthly ,notices of the ,r4,a4,s41 vol4 xxxii4 #d4 ,this eruptive force1 whatever be its nature1 is probably common to the sun and the so-called fixed stars4 ,if so1 the dispersed fragments of ejected matter ought to be found in the spaces intervening between sidereal systems4 ,accordingly1 the phenomena of comets and meteors have demonstrated the existence of such matter1 widely diffused1 in the portions of space through which the solar system is moving4 #e4 ,according to ,mr4 ,sorby the microscopic structure of the aerolites he has examined points evidently to the fact that they have been at one time in a state of fusion from intense heat1--a fact in striking harmony with this theory of their origin4 #f4 ,the velocity with which some meteoric bodies have entered the atmosphere has been greater than that which would have been acquired by simply falling toward the sun from any distance1 however great4 ,on the theory of their sidereal origin1 this excess of velocity has been dependent on the primitive force of expulsion4 ,the shower of aerolites which fell at ,pultusk1 ,poland1 on the #cjth of ,january1 #ahfh1ca is not only a remarkable illustration of the fact here stated1 but also of another which may be accounted for by the same theory1 viz43 that meteoric bodies sometimes enter the solar system in groups or clusters4 #ca ,see ,chapter ,,vii4 #g4 ,a striking argument in favor of this theory may be derived from the researches of the late ,professor ,graham1 considered in connection with those of ,dr4 ,huggins and other eminent spectroscopists4 ,professor ,graham found large quantities of hydrogen confined in the pores or cavities of certain meteoric masses4 ,now1 the spectroscope has shown that the sun's rose-colored prominences consist of immense volumes of incandescent hydrogen2 that the same element exists in great abundance in many of the fixed stars1 and even in certain nebul2 and that the star in the ,northern ,crown1 whose sudden outburst in #ahff so astonished the scientific world1 afforded decided indications of its presence4 ,,the ,,end4 ,,by ,,the ,,author ,,of ,,this ,,volume4 ,,meteoric ,,astronomy3 ,a ,,treatise ,,on ,,shooting ,,stars1 ,,fire ,,balls1 ,,and ,,aerolites4 ,,by ,,daniel ,,kirkwood1 ,,ll4,d4 #abmo4 ,extra ,cloth4 #a4ej4 ,for sale by ,booksellers generally1 or will be sent by mail1 postpaid1 on receipt of the price by ,j4 ,b4 ,,lippincott ,,co41 ,publishers1 #gae and #gag ,market ,st41 ,philadelphia4 ,transcriber's ,note3 ,obvious errors in spelling and punctuation have been corrected4 ,footnotes have been renumbered and moved from the page end to the end of the paragraph4 ,images have been moved from the middle of a paragraph to the closest paragraph break4