[ocr errors]

or run over (evolvatur) as if it were a was before them, and their labours fable, without fatiguing the attention, were so amply rewarded, that their fucor dwelling upon the difficulties.” ceffors who inherit the advantage of

This truly great man though he their toil can scarcely forbear to envy wanted strength to withstand the their fame. This can only be faid of temptation of becoming the founder such discoveries as may in some meaof á fyftem, has furnished the world sure be called accidental, but the revowith arguments by which the ancient lution which the state of natural philotheories were overthrown, and which, fophy experienced from the exertions in their operation, destroyed even that of Newton reflects a degree of fame upon which he himself had bestowed fo on that author which all nations and much labour. He taught men to think men have been proud to confirm. for themselves, and those arguments This philosopher possessed a strength which from the pen of the great Ve- of mind, which, added to his other perrulam not a century before had been fections, render him without hyperbole offered without effect, were heard in the boast and glory of mankind. Very a more inquiring age from the elegant early in life he had mastered the circle and active Descartes. Gassendi an en- of human learning, and added entire lightened and penetrating genius at- sciences to those already discovered and tempted to revive the doctrines of Epi- perfected. The discovery of universal curus with confiderable alterations, but gravity was obscurely made for ages he was not attended to. The multi- before his time, as we have already tode had followed Descartes, and the observed, but the greater discovery of few who think for themselves saw too the laws to which the supreme geofar into the extensive field of unculti- meter has subjected the universe was vated science to think of embracing reserved for him. His skill in making any system. Britain, the first in re experiments was not less to be admired ftoring the empire of reason and sim- than the facility with which he arplicity to philosophy, was already in ranged them, so as to mutually illuftrate possession of many of those enlarged each other, and point out the real minds who can withhold their affent theory of nature. The science of till proof can be obtained, and attached Dioptrics, first fyftematized by Descartes, only to truth are capable of viewing took a new form from the discoveries without prejudice, and relating with of Newton; and the nature of light fidelity. ` Above the mean ambition of and colours, which had been the subject attempting to reap fame from casual of endless disquisitions among philodiscoveries, they met, and communi- fophers, became one of the most percated respectively their intentions and spicuous parts of natural knowledge. pursuits. The sich harvest of nature

(To be continued.)



IFE, the sacred writings inform But a moment! What are threescore

us, is but a vapour which appear- years and ten, when put in competieth for a little while and then vaniiheth tion with everlasting ages ; but a span! away; and fo it is proved to be daily, yea, less than a span and nothing: yet by the deaths of infants and young in so short a space how much is to be people in general: indeed, by far the done?-What am I? Where am I gogreatest part of mankind die under ing? and what will be my portion in three years of age: nascentes morimur is another and eternal world ? are qaefa motto as often verified as the morn tions suited to dying immortals, and returns, or fable evening yields the should be matter of daily and serious world to night. Alas! what is the confideration. longest life compared with eternity?


HE following account of the discovery of the GEORGIUM SIDUS, drawn

up the London Magazine, will, we doubt not, prove entertaining and instructive to the lovers of astronomy. ACCOUNT OF THE NEW PLANET, DISCOVERED BY MR. HERSCHEL, OF BATH, AND BY HIM, IN COMPLIMENT TO HIS MAJESTY, CALLED


TR. HERSCHEL has for many wards, and then found it was changing years

to the its situation at the rate of about 2 in fracting of reflecting telescopes for his an hour. amusement, and has succeeded so far, Assured of this, Mr. Herschel wrote that he makes them to bear magnify- immediately to the Royal Society, ining powers of an almost incredible big- forming them of his discovery, that neis-not less than between fix and se- other astronomers might join in the obven thousand times! The effect which fervation of it: but not mentioning, in these very large magnifying powers had his first letter, that it was neceffary to on the appearance of the fixed stars, in use a very large magnifying power to shewing many to be double, triple, and distinguish it from a fixed ftar, they even quadruple, which were before did not inmediately discover it. This thought to be single stars, suggested to point being, however, explained, the Mr. Herschel the idea of attempting Astronomer Royal, as well as Professor to discover the parallax of the fixed Hornsby of Oxford, detected it immeftars by their means.

diately; and the former, almost as soon It was in pursuit of this object that as he saw it, declared his fufpicions Mr. Herschel was examining the small (extraordinary as the case seemed) that stars near the feet of Gemini, on the it was not one of that species of bodies 13th of March, 1781, between the which we ordinarily cail comets, but à hours of ten and eleven at night; when planet belonging to our fyftem, of the he took notice of one, vitībly larger fame nature with the ret, although, than the rest : being struck with its on account of its finall fize and remote uncommon magnitude, he compared it situation, it had escaped the observawith H. Geminorum, and the small itar tions of astronomers to this time. in the quadrangle, between Auriga and On the ift of April, Dr. Markelyne Gemini, and finding it so much larger wrote an account of this discovery to than they, though not quite so bril- the astronomers at Paris, and other liant, began to suspect that it was a co- places abroad, fo that in a very little met. To determine this point, he ex time, observations were made on this amined it with different magnifying very extraordinary phenomenon in most powers, from 227, the power with parts of Europe. In France it has been which he discovered it, to 2010; and observed very affiduously by Meff

. le found, continually, that the diameter Monier, De lá Lande, Mellier, Méchain, of the comet (as he supposed it to be) D'Argelet, Lévesque, and Darquier; increased in proportion to the power; in Sweden by Melf

. Wargentin and contrary to what is universally known Prosperin; by M. Bodé, at Berlin; and to be the case when different magnify- by Mlett

. Reggio, the Cæsaris, and ing powers are applied to the fixed siopé, in Italy; and, doubtless, by maftars. But in order to obtain absolute ny others whose observations have not certainty in this point, he measured its come to my knowledge. distance froin some of the neighbour Towards the latter end of May it ing fixed stars, with which he com- approached so near to the son as to pared it again a night or two after- preclude all further observations at that

LOND. MAG. July 1783.


[ocr errors][ocr errors]

time; and, therefore, M. Lexell, who this planet's orbit; but crery one fup-
happened then to be in England, applied posing it a comet, and not a planet, re-
himself to compute, as well as the few volving round the fun in an orbit near-
obfervations of which we were then in ly circular, the diameter of which was
poffeffion would admit, theelements ofits about 18 times that of the earth, though
orbit, in the same manner that the ele- they represented some of the observa-
ments of the orbits of comets have been tions well enough, yet others, made
usually computed: that is to say, by within a few days of these, were very
assuming the perihelion distance of it far from the truth. The President
from the sun, and then describing a pa- de Saron, indeed, so early as the 8th
rabola with this focal distance, through of May, declared that its distance from
three assigned points, or observed places the fun could not be less than 12 times
in the heavens. In the process of this that of the earth, from the observations
business M. Lexcll assumed, one after which had hitherto been made to agree
another, the several perihelion distances with any tolerable exactness to the com-
6, 8, 10, 12, 14, 16, and 18 times the putations. In the beginning of June
distance of the fun from the earth; but the Abbe Boscovich printed a very learn-
he found, on comparing these several ed memoir on this subject, in which,
assumptions with the observations, that by a very simple and ingenious process,
when he assumed the perihelion distance he shewed that there were four differ-
somewhere between 14 and 18 times ent parabolas which the planet might
the distance of the sun from the earth, be supposed to move in, and yet to
the calculations agreed best with the correspond equally well with the obfer-
observations: it appeared, however, to vations that had then been made. Soon
him then that it was almost indifferent after M. de la Place gave us elements of
what perihelion distance he took be- this orbit in the Connoissance des Temps
tween these two limits, as the agree- for 1784, deduced entirely from the
ment of the calculations with the ob- observations of M. Mefficr. He made
servations was nearly the same in every the perihelion distance 9.4404; the
one of them; but, in some degree, time of the perihelion January 27th,
faulty in all: and as it was impollible 1790, at 6 h. 19' app. time, by the
to determine whether this disagreement meridian of Paris, and its place ing 28°
arose from the small errors which the 12'30"
observations were liable to, or from the On the 16th of July the planet was
affumption of a false hypothesis, he again obferred by Profeffor Hornsby
laid the business aside until observations at Oxford, after its conjunction with
better suited to the purpose could be the sun; and a day or two afterwards
obtained. Some, however, found that by the Astronomer Royal at Greenwich.
all the observations would agree better M. Messier observed it on the irth,
with calculations founded on an hypo- at Paris; and these three gentlemen
thesis nearly circular, than any other, continued contantly to observe it, when
and that the radius of this circle ought the state of the heavens would permit
to be about 18 times that of the earth's them, to the time of its opposition with

. This circumstance seemed strong- the fun; which happened, according to
ly to favour Dr. Maikelyne’s surmise, M. de la Lande's calculations, from
that the newly discovered star was a the observations of M. Méchain on the
planet, appertaining to our system; 21st of December, at 18 h. 3', mean
and his opinion would have gained time at Paris: the place of the planet
ground faster than it did, if Mr. Her being then 5 0° 20'15", and its geo-
fchel's observations of its diameter, the centric latitude oo 15'6"N.
very extraordinary accuracy of which Towards the latter end of the year,
he strongly infifted on, had not tended Mr. Lexell having informed M. de la
to prove that its motion was then al- Lande that in Englandits motion was ve-
molt in-a direct line towards the earth. ry well represented b: a circle, fet about

Trials were made abroad by different computing the elements of its orbit on persons to determine the elements of that hypothelis. He made choice of


[merged small][merged small][ocr errors]

three observations, which appeared to Finding his hypothesis to agree so him very good ones; being all con well, thus far, M. de la Lande profirmed by those which immediately ceeded to calculate about 30 other obpreceded and followed them: the firít servations, made by Dr. Mafelyne, and last were by M. Méchain, and the M. Le Monier, M. Messier, M. Méchain, fecond by M. Meflier. The first of M. D'Argelet, M. Levesque; and these observations was made the 25th himself; some before, some in, and of April, the second on the 31st of others after the interval of 231 days, July, and the third on the 12th of above spoken of; and he had the satisDecember, 1781: all before the first faction to find they all agreed, reasonopposition of the planet with the sun. ably well, with the computations, exFrom these observations M. de la Lande cept two which were made about the deduced the geocentric longitudes and beginning of April 1781, and a few latitudes of the planet; and by assuming made in the course of last summer. In its distance from the sun, he calculated these calculations, M. de la Lande supthe parallax of the annual orbe, and posed that the heliocentric longitude of from thence the heliocentric longitudes the planet on the ift of January 1782, and latitudes, at the time of the first at noon, by the meridian of Paris, was and latt observations: thus he obtained 35.00 59' 22'', and its motion with the motion of the planet, as seen from respect to the equinoxes 4° 22' 22? the fun, in 231 days, the time between annually. He used the solar places of the observations. Using still the fame M. de la Caille. distance which ho had assumed for calci Finding that the errors of his hypolating the parallax of the annual orbe, by thesis amounted to 2' in July 1782; the help of Kepler's rule, he computed M. de la Lande set himself to examine the time of one revolution of the what alterations it would require to planet by the fixed stars; and thence its make the calculations agree with the motion in 2 31 days from the mean equi- observations made about that time, as nox; which motion should be the same well as with those made in the beginas that seen from the sun, and deduced ning of April 1781, and found that to from the observations, supposing the do this the distance of the planet from assumed distance of the planet from the the fun must be 18,893, the time of a fun to be true. But as it turned out revolution 82,12 years, the mean daily otherwise, he varied the distance of the motion, from the equinoxes, 43":22, planet from the sun, and repeated his and the mean heliocentric longitude, calculations, until the heliocentric mo- on the ist of January 1782, at noon, tion, computed by this means, from 381010". But he found also, that the observations, agreed with that if he adopted these numbers, the caldrawn from the interval of time and culations would differ from the obserduration of a revolution, found with vations near a minute and half at the the same distance. In this manner M. oppofition, in December 1781; he, de la Lande found that it was necessary therefore, concluded that these anomato suppose the distance of the planet lies indicated an inequality in the real from the fun 18.931 semi-diameters of motion of the planet, agreeable to what the annual orbe, and the duration of a is observed in the motions of the others; revolution 82,37 years. He afterwards but that this inequality is so small as to took the observation of the 31st of Ju- render it unnecessary, at present, to ly, between which and the first of the seck for any other orbit than a circle; three there was an interval of 97,24 and that we must not expect to discover days; and calculated, by means of the the true quantity of the central equaelements deduced above, the geocentriction without the observations of many longitude, which he found to be only years. 5." more than that deduced from the M. de la Lande has also made fome observation; a greater agreement than effays to discover the place of the node, the observations require, as they can, and the inclination of the orbit of this by no means, be depended on to twice planet to the plane of the ecliptic; but that quantity.


D 2

the small motion in latitude renders it and, moreover, notwithstanding he had very difficult to determine these points searched very carefully for that star in with any tolera!le certainty at present: the heavens he had not been able to tire geocentric latitudes observed on the find it. Should this suppoi.ticn be 25th of April and the 12th of Decem- well founded, and Mr. Nayer's origiber, 1781, were 1' 35", and 14'54", nal papers, where he minuted down the Dorth: which being reduced to the sun, observations which he made for detergive the heliocentric latitudes, at these miring the fituations of the ftars in two times, 11' 59', and 14'8"'; and that cataicgue ve found, as it is prothese, with the ination in longitude bable they may;* those observations between the two observations, 2046'3", would be of the utmost importance in give the planet's dittance from the node, feeling the mean motion of this planet, on the 25th of April, 1701, 150 4', as well as some of the elements of its and of course the place of the node orbit. Z: 12° 55' The inclination comes out In April, 1782, M. Bod composed 0° 46'

another memoir on this subject, in Again, the observed geocentric lati- which he observes that 'Tycho placed a tudes on the roth of April 1781, and star of the fixth magnitude a little above on the 26th of March 1782, were 1' u in the tail of Capricorn, which He48", and 15'5", and the heliocentric velius, after the most laborious search, latitudes deduced fin there were 12' could never find: he, therefore, con7'', and 15'10"; the aitference of the cludes that this star also was the Georobserved longitudes was 4° 7' 44''; and gium Sidrs; more especially, as his these give the place of the node 2° 12° calculations place it very near that fi2'; and the inclination of the orbit oo tuation in the beginning of 1587. 44. M. de la Lande thinks this de These circumstances have induced termination rather more to be depended M. de la Lande to wilh that the small on than the former. According to these stars which are placed in M. de la numbers the planet passed its node about Caille's catalogue, about the equifour years ago, and it will be at its noctial point Arics, were re-examined; greatest north latitude about the year as he is in poffeffion of that astrono1798.

mer's original observations; and, there. M. Bode, of Berlin, who has been fore, if it thould appear that very affiduous in observing this planet, of those stars had disappeared which he published a merroir upon it in the E- places near the situation the planet muft phemerides Allemande, for 1784, print- have been in about the year 1761 or ed in the latter end of 1781. He 1762, the time when M. de la Caille also adopts the circular hypothesis; and made his observations, there would be found, that to make the observations the greatest reason to suppose it must agree with the computations from it, have been this planet. for the fame the distance must be 18,928. He ob- reason, it would, perhaps, be adviseable ferves afterwards, that the star, No.964, to enquire into the fituation which this in Mayer's catalogue, where the places planet was in when Mr. Flamstead and of the stars are adjusted to the begin- Dr. Bradly made their observations; uing of the year 1756, was very pro- and whether fome one of the stars, bably the GEORGIUM SIDUS, because, which they have placed in that part of according to his calculations, the pla- the heavens, may not have left it; as net must have been very nearly in that by this means we may, perhaps, meet fituation about the year 1755 or 1756: with obfervations sufficient to settle the

theory Since ihis was written, I have seen a letter from M. Méchain, of the Royal Academy of Sciences, at Paris, dated June 18 h, in which he assures us thefe papers of Profeflor Mayer áre found; and that it appears from thence ihis celebrated attıonomer observed the far, 964 in his catalogue, but once, If he had been lucky enough to have oblerved it a second time, he rnult lave made the discovery which has been reserved for Mr. Herschel. How equally's and frugally, Providence diípentes iis bounties of every kind! M. Mayer's labours and disco. veries were alıcády sufficient to perpetuate his name; and needed not this addition to them.

any one

« ElőzőTovább »