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cinders, I have constantly observed The filh is seven inches long, two that the lava has soon after made inches and a half broad, has a long its appearance, either by boiling projecting mouth, and seems to be over the crater, or forcing its pas- of the genus Tetrodon. The back sage through crevices in the conical of the fish is a dark brown colour, part of the volcano. As long as I the belly part of fea-green, the remain in this country, and have sides yellow, and the fins and tail the necessary assistance of the above- of a fandy green. The body is inmentioned ingenious Monk (who is terspersed with red, green, and as excellent a draughtsman as he is white spots, the white ones particuan accurate and diligent observer) larly bright; the eyes large, the the Vesuvian diary fall be conti- iris red, its outer edge tinged with nued ; and I hope one day to have yellow, the honour of presenting these curi.. The island of Johanna is situated ous manuscripts (which begin now in latitude 12° 13' south. The coast to be voluminous) to the Royal So- is wholly composed of coral rocks, ciety, if it should think them wor- which are in many places hollowed thy of a place in the Library of the by the sea. In these cavities I Society.
found several of the electrical fishes. The water is about 56° or 60° of
heat of Fahrenheit's thermometer. An account of a new Electrical Fish.. I caught two of them in a linen
In a letter from Lieutenant Wil- bag, clofed up at one end, and open liam Paterson to Sir Joseph Banks, at the other. In attempting to take Bart. P. R. S. From the same.
one of them in my hand, it gave
me so severe an electrical shock, Sir,
that I was obliged to quit my hold.
na, one of the Comora liner bag, and carried them to the islands, in my way to the East-Indies, camp, which was about two miles with the 98th regiment, I met with diftant. Upon my arrival there, an electrical fish, which has hither- one of them was found to be dead, to escaped the observation of natu- and the other in a very weak state, ralists, and seems in many respects which made me anxious to prove, to differ from the electrical fishes by the evidence of others, that it already described; which induces possessed the powers of electricity, me to send you the following ac- while it was yet alive. I had it count of it, with a very imperfect put into a tub of water, and desired drawing, and to beg that, if you the surgeon of the regiment to lay think it deserves attention, you will hold of it between his hands ; upon do me the honour of presenting it doing which he received an evident to the Royal Society. The situation electrical stroke. Afterwards the of a subaltern officer, in an army adjutant touched it with his finger upon foreign service, will, I hope, upon the back, and felt a very flight fufficiently apologize for my fend- fhock, but sufficiently strong to aling you so very imperfect a sketch certain the fact. of the fish, which was made in the After so very imperfect an acfield, in a hot climate, under every count, I will not trouble you
any obfervations of my own upon that the, vague observations of the this fingular fish ; but beg you will comet, made by Apian in 1532, consider this only as a direction to might rather detract from, than add others who may hereafter visit that to, the evidence arising from more island, and from their situation, and certain data. Astronomers, howknowledge in natural history, may ever, have generally acquiesced in be better able to describe the fish, his first conjecture of the comets and give an account of its electri- of 1532 and 1661 being one and cal organs.
the same, and to expect its return I have the honour to be, with to its perihelium accordingly in great esteem, &c.
The interval between the passa.
in 1532 and 1661 is 128 years, 89
days, 1 hour, 29 minutes, (32 of Advertisement of the expected return the years being biffextile) which,
of the Comet of 1532 and 1661 in added to the time of the perihelium ibe year 1788. By the Rev. Ne. in 1661, together with 11 days to vil Maskelyne, D. D. F. R. S. reduce it from the Julian to the and Astronomer Royal. From the Gregorian ftile, which we now use, fame.
brings out the expected time of the
next perihelium to be April 27th, HE comet of 1531, 1607, and 1 h. 1o' in the year 1789.
1682, having returned in the The periodic times of the comet, year 1759, according to Dr. Hal- which appeared in 1531, 1607, and ley's prediction in his Synopsis Astro- 1682, having been of 76 and 75 zomie Cometicæ, first published in years alternately, Dr. Halley supthe Philosophical Transactions in posed, that the subsequent period 1705, and re-published with his would be of 76 years, and that it Astronomical Tables in 1749, there would return in the year 1758 ; is no reason to doubt that all the but, upon considering its near apother comets will return after their proach to Jupiter, in its descent toproper periods, according to the re- wards the fun in the summer of 1681, mark of the same author.
he found, that the action of Jupiter In the first edition of the Synopfes upon the comet was, for several he supposed the comets of 1532 and months together, equal to one-fif. 1661, from the similarity of the tieth part of the sun upon it, tendelements of their orbits, to be one ing to increase the inclination of the and the fame; but in the second orbit to the plane of the ecliptic, edition he has seemed to leffen the and lengthen the periodic time. weight of his firft conjecture by not Actordingly, the inclination of the repeating it. Probably he thought orbit was found by the observations it beft to establish this new point in - made in the following year 1682 to aftronomy, the doctrine of the re- be zz' greater than in the year 1607. volution of comets in elliptic or- The effect of the augmentation of bits, as all philosophical matters in the periodic time could not be seen the beginning should be, on the till the next return, which he sup, most certain grounds; and feared pafed would be protracted by Ju.
piter's action to the latter end of the ceed the latter, and consequently year 1758, or the beginning of the periodic time would be short1759. M. Clairaut, previous to ened; but probably not much, on its return, took the pains to calcu. account of the considerable distance late the actions both of Jupiter and of the comet from the planets when Saturn on it during the whole pe- it passed by them; and therefore riods from 1607 to 1682, and from we may still expect it to return to 1682 to 1759, and thence predicted its perihelium in the beginning of its return to its perihelium by the the year 1789, or the latter end of middle of April; it came about the year 1788, and certainly some the middle of March, only a month time before the 27th of April 1789. fooner, which was a sufficient ap- But of this we shall be better inproximation to the truth in so deli- formed after the end of this year, cate a matter, and did honour to this from the answers to the prize ques. great mathematician, and his labo- tion proposed by the Royal Academy rious calculations.
of Sciences at Paris, to compute The comet in question is also, the disturbances of the comet of from the position of its orbit, liable 1532 and 1661, and thence to preto be much disturbed both by Ju- dict its return *. piter and Saturn, particularly in If it should come to its periheits ascent from the sun after palling lium on the ift of January 1789, its perihelium, if they should hap- it might probably be visible, with pen to be near it, when it approaches a good achromatic telescope, in its to or crosses their orbits; because descent to the sun, the middle of it is very near the plane of them at September 1788, and sooner or lathat time. When it passed the or- ter, according as its perihelium -bit of Jupiter in the beginning of thould be sooner or later. It will
February 1682, O. S. it was 50° approach us from the southern parts in consequentia of that planet ; and of its orbit, and therefore will first when it passed the orbit of Saturn appear with considerable south lati. in the beginning of October 1663, tude and fouth declination; so that it was 17° in consequentia of it. persons residing nearer the equator Hence its motion would be accele. than we do, or in fouth latitude, rated while it was approaching to- will have an opportunity of discowards the orbit of either planet by vering it before us. It is to be its separate action, and retarded wished that it may be first seen by when it had passed its orbit; but, fome astronomer in such a situation, as it would be subjected to the effect and furnished with proper inftruof retardation through a greater ments for settling its place in the part of its orbit than to that of ac- heavens, the earliest good observa. celeration, the former would ex- tions being most valuable for de
Since this was written, I received the unwelcome news, in a letter from M. Mechain, of the Royal Academy of Sciences at Paris, that the Academy has not received satisfactory answers concerning the disturbances of the comet between 1532 and 1661, and 1661 and the approaching return, and that the prize is referred to be adjudged of at Easter 1788, and that it will be 6000 livres. N. M. I
terming its elliptic orbit, and prov- tudes and latitudes, and ditances ing its identity with the coniets of from the earth, must bere-computed 1532 and 1661. The Cape of Good accordingly. The calculations are Hope would be an excellent situation made for a parabolic orbit
from the for this purpose.
elements, determined by Dr. HalIn order to assist astronomers in ley from Hevelius's observations in looking out for this comet, I have 1661, only allowing for the prehere given its heliocentric and geo. cession of the equinoxes. The elecentric longitudes and latitudes, and ments made ule of were as folcorrespondent distances from the sun lows : and earth, on fuppofition that it Time of perihelium January 1, Thall come to its perihelium on Ja- 1789, at noon. nuary 1, 1789. But if that should
Perihelium distance, 0,44851. happen sooner or later, the helio. Place of ascending node 23 24 centric longitudes and latitudes, and 18'. distances from the fun, will stand Inclination of orbit to the eclipgood if applied to days as much tic 32° 36'. earlier or later, as the time of the Perihelium forwarder in orbit perihelium may happen fooner or than the ascendirg node 33° 28'. later; and the geocentric longi- Its motion is direct.
Computed places of the Comet, on fuppofition that it fall return to its peri
belium January 1, 1789, at noon.
tric latithe longitude.
Product of Geocen
distances tric lati
S. D. M.D. M. S. D. M.D. M, Apr. 23, 74, 04,5211 3 5430 56 SW 16 30 27 5 S 18,07 June 4, 13, 5/3,5411 7 631 25
11 26 31131 4 12,38 July 14, 53, 2,57 11 11 1631 55 3 21138
7,70 Aug. 2,462,752,1511 13 47 32 10 4 842 59 20,432, 51,7911 16 39 32 22
0/48 16 Sept. 7, 32,25 1,5111 20 932 32
3,39 24, 02, 1,2911 24 1632 36 11 13 12 56 45
2,58 Oct. 10,26 1,75 1,1311 29 24 32 30
10 28 22 56 36 1,75 26,64 1,50 1,01 0 5 51132 4 10 15 50 52 6 1,51 Nov. 9,34 1,25 0,88 0 14 1931
8 36 46 47
1,10 23,391, 00,76 o 26 428 32
4 1039 Dec. 7,2110,75/0,62 1 13 58 22 29 9 29 18 27 45 0,46 23,320,500,50 2 20 58 2 8
9 14 311 2 7 S 0,25 24,35 0,49 0,51 2 24 18 o 9 12 58100 0,25 1789 Jan. 1, ol0,4510,59 323 25 17 17 N) 2 50113 8N 0,26
The last observation made by leet into one point of view the meHevelius on the comet in 1661 morable instances of long-lived perwas when its distance from the fons, whose ages are recorded by earth was 0,986, and from the monumental inscriptions, biograsun 1,37, with what he calls a very phical writings, or even by the publong and good telescope ; at which lic prints. The only judicious attime it appeared faint and small tempt I have yet seen of this kind, with it, though still sufficiently vi- was by the ingenious Mr. Whitesible. Let us suppose this to have hurst, a few years ago, in his Inbeen a telescope of 9.feet focal quiry into the Origin and Formation length, with an aperture of 1,65 of the Earth. To the examples of inch ; then, because the diameter of longevity mentioned by him, as colthe aperture of a telescope sufficient lected by a person of veracity from to render the comet equally visible the above fources, I have now addshould be as the product of its diio ed sundry remarkable instances of tances from the fun and earth, and a fimilar kind, as they have occurthe product of the numbers above. · red to me in the course of reading ; mentioned 0,986 and 1,37 is 1,35, and have annexed the authorities, we shall have the following analogy (so far as was practicable) that you to find the aperture of a refracting may be enabled to judge of the detelescope fufficient to fhew the co gree of credibility, that may seem met as it appeared to Hevelius. As due to the respective facts, and of the 1,35 : 1,65 inch :: 9 : 11 inches, ' allowance which it may appear neso is the product of distances from cessary to make, for that natural prothe sun and earth to the diameter pensity, which mankind have ever of the aperture required in inches. betrayed for the marvellous. Now,
admitting that many of the ages may
have been somewhat exaggerated, Observations on Longevity. By An- yet still there can be no possible doubt,
thony Fothergill, M. D. F. R.S. that even these have extended far beCommunicated in a Letter to Dr. 'yond the ordinary period of life, and Percival. From Memoirs of the may therefore beentitled to a place in Literary and Philofophical Society the following tables, which I submit of Manchester.
to your connderation, as a small spe
cimen of what might be more worthy Dear Sir,
your attention, it conducted hereaf Have often thought, it would ter on a larger scale, and pursued be an useful undertaking to col- with chronological accuracy.