Page images
PDF
EPUB

fufpected the glass to be covered with damp, or the eye out of order: but yet a ftar of the 10th or 11th magnitude, juft north of it, was free from the fame appearance. A fecond obfervation calls it one of the most remarkable phænomena I ever have feen, and like my northern planetary nebula in its growing ftate.

"The connection between the ftar and the milky nebulofity is without all doubt.

" November 3, 1787. A bright ftar with faint nebulofity. A fecond obfervation mentions the far to be of the 9th magnitude, and the faint nebulofity of very little extent.

[ocr errors]

June 11, 1787. Sufpected, fiellar. By a fecond obfervation it is verified, and called a very small star involved in extremely faint nebulefity.

"November 25, 1788. A ftar of about the 9th magnitude, furrounded with very faint milky nebulofity; other ftars of the fame fize are perfectly free from that appearance. Less than 'in diameter. The far is either not round or double.

"March 23, 1789. A bright, confiderably well defined nucleus, with a very faint, jmall, round chevelure.

"The connection admits of no doubt; but the object is not perhaps of the fame nature with thofe which I call cloudy ftars.

"April 14, 1789. A confiderable, bright, round nebula; having a large place in the middle of nearly an equal brightness, but lefs bright towards the margin.

"This feems rather to approach to the planetary fort.

"The connection is not to be doubted.

“March 19, 1799. A very bright nucleus, with a fmall, very faint chevelure, exactly round. In a low fitu ation, where the chevelure could hardly be jeen, this object would put on the appearance of an ill-defined, planetary nebula. of 6, 8, or 10" diameter.

"November 13, 1790. A most fingular phenomenon: a far of about the 8th magnitude, with a faint luminous atmosphere, of a cir cular form, and of about 3' in diameter. The far is perfectly in the center, and the atmosphere is fo diluted, faint, and equal throughout, that there can be no furmife of its confifting of fars; nor can there be a acubt of the evident connection between the atmosphere and the fiar. Another ftar, not much less in brightness, and in the fame field with the above, was perfectly free from any fuch appear

"March 5, 1790. A pretty con fiderable star of the 9th or 10th magnitude, vifibly affected with very faint nebulofity of little extent, all around. A power of 300 fhewed the nebulofity of greater extenf.

ance.

"This laft object is fo decifive in every particular, that we need not hesitate to admit it as a pattern, from which we are authorized to draw the following important confequences.

"Suppofing the connection between the ftar and its furrounding nebulofity to be allowed, we argue, that one of the two following cafes muft neceffarily be admitted. In the first place, if the nebulofity confift of ftars that are very remote, which appear nebulous on account of the fmall angles their mutual diftances fubtend at the eye, whereby they will not only, as it were, run into one another, but also appear extremely faint and diluted; then, what must be the enormous fize of the central point, which outlines all the reft in fo fuperlative a degree as to admit of no comparifon? In the next place, if the ftar be no bigger than common, how very

НА

fmall

fmall and compreffed must be those other luminous points that are the occafion of the nebulofity which furrounds the central one? As, by the former fuppofition, the luminous central point muft far exceed the ftandard of what we call a ftar, fo, in the latter, the thining matter about the center will be much too small to come under the fame denomination; we therefore cither have a central body which is not a ftar, or have a ftar which is involved in a fhining fluid, of a nature totally unknown to us.

I can adopt no other fntiment than the latter, fince the probability is certainly not for the existence of fo enormous a body as would be required to fine like a star of the 8th magnitude, at a distance fufficiently great to caufe a vaft fyftem of stars to put on the appearance of a very diluted, milky nebulofity.

But what a field of novelty is here opened to our conceptions; a hining fluid, of a brightnefs fufficient to reach us from the remote regions of a star of the 8th, 9th, eth, 11th, or 12th magnitude, and of an extent fo confiderable as to take up 3, 4, 5, or 6 minutes in diameter! can we compare it to the corufcations of the electrical fluid in the aurora borealis? or to the more magnificent cone of the zodiacal light as we fee it in fpring or autumn? the latter, notwithstanding I have obferved it to reach at least 90 degrees from the fun, is yet of fo little extent and brightnefs as probably not to be perceived even by the inhabitants of Saturn or the Georgian planet, and must be utterly invifible at the remotenefs of the nearest fixed star.

"More extensive views may be derived from this proof of the exiftence of a thining matter. Per

haps it has been too haftily furmised that all milky nebulofity, of which there is fo much in the heavens, is owing to ftarlight only. Thefe, nebulous ftars may ferve as a clue to unravel other myfterious phænomena. If the fhining fluid that fur, rounds them is not fo effentially connected with these nebulous stars but that it can alfo exift without them, which feems to be fufficiently pro. bable, and will be examined here. after, we may with great facility explain that very extenfive, telescopic nebulofity, which, as I mentioned before, is expanded over more than fixty degrees of the heavens, about the conftellation of Orion; a luminous matter accounting much better for it than chuftering stars at a diftance. In this cafe we may alfo pretty nearly guess at its fituation, which muft commence fom where about the range of the ftars of the th magnitude, or a little farther from us, and extend equally in fome places perhaps to the regions of those of the 9th, cth, 11th, and 12th. The foundation for this furmife is, that, not unlikely, fome of the stars that happen to be fituated in a morẹ condenfed part of it, or that perhaps by their own attraction draw together fome quantity of this fluid greater than what they are entitled to by their fituation in it, will, of course, affume the appearance of cloudy ftars; and many of thofe I have named are either in this stratum of luminous matter, or very near it.

"We have faid above, that in nebulous ftars the existence of the fhining fluid does not feem to be so eflentially connected with the central points that it might not alfo exist without them. For this opinion we may affign feveral reasons. One of them is the great refemblance between the chevelure of thefe ftars

and

and the diffufed extenfive nebulofity mentioned before, which renders it highly probable that they are of the fame nature. Now, if this be ad mitted, the separate existence of the luminous matter, or its independance on a central ftar, is fully proved. We may alfo judge, very confidently, that the light of this fhining fluid is no kind of reflection from the ftar in the center; for, as we have already obferved, reflected light could never reach us at the great diftance we are from fuch objects. Befides, how impenetrable would be an atmosphere of a fufficient denfity to reflect fo great a quantity of light; and yet we obferve, that the outward p parts of the chevelure are nearly as bright as thofe that are close to the ftar; fo that this fuppofed atmofphere ought to give no obftruction to the paffage of the central rays. If, therefore, this matter is felf-luminous, it feems more fit to produce a ftar by its condenfation than to depend on the ftar for its ex

iftence.

[ocr errors]

"Many other diffufed nebulofities, befides that about the conftellation of Orion, have been obferved or fufpected; but fome of them are probably very diftant, and run out far into fpace. For inftance, about minutes in time preceding & Cygni, I fufpect as much of it, as covers near four fquare degrees; and much about the fans quantity 14 preceding the 125 Tauri. A space of al, moft 8 fquare degrees, 6' preceding Trianguli, feems to be tinged with milky nebulofity. Three minutes preceding the 46 Eridani, ftrong, milky nebulofity is expanded over more than two fquare degrees, 54′ preceding the 13th Canum venaticorum, and again 48' preceding the fame ftar, I found the field of view affected with whitish nebulofity

throughout the whole breadth of the fweep, which was 2° 39′ 4′′ following the Cygni, a confider. able fpace is filled with faint, milky nebulofity, which is pretty bright in fome places, and contains the 7th nebula of my Vth clafs, in the brighteft part of it. In the neighbourhood of the 44th Pifcium, very faint nebulofity appears to be diffused over more than 9 fquare degrees of the heavens. Now, all thefe phenomena, as we have already feen, will admit of a much easier explanation by a luminous fluid than by ftars at an immenfe diftance.

"The nature of planetary nebule, which has hitherto been involved in much darknefs, may now be explained with fome degree of fatisfaction, fince the uniform and very confiderable brightnefs of their apparent difk accords remarkably well with a much condenfed, luminous fluid; whereas to fuppofe the m to confift of clustering stars will not fo completely account for the milkinefs or foft tint of their light, to produce which it would be required that the condensation of the stars fhould be carried to an almoft inconceivable degree of accumulation. he furmife of the regeneration of ftars, by means of planetary nebule, expreffed in a former paper, will become more probable, as all the luminous matter contained in one of them, when gathered toge ther into a body of the fize of a star, would have nearly fuch a quantity of light as we find the planetary nebuke to give. To prove this expe rimentally, we may view them with a telefcope that does not magnify fufficiently to fhew their extent, by which means we fhall gather all their light together into a point, when they will be found to affume the ap, pearance of fmall ftars; that is, of

ftars

ftars at the distance of those which we call of the 8th, 9th, or cth magnitude. Indeed this idea is greatly fupported by the difcovery of a well defined, lucid point, refembling a star, in the centre of one of them; for the argument which has been used, in the cafe of nebulous ftars, to fhew the probability of the existence of a luminous matter, which refted upon the disparity between a bright point and its furrounding fhining fluid, may here be alledged with equal juftice. If the point be a generating ftar, the fur ther accumulation of the already much condensed, luminous matter, may complete it in time.

"How far the light that is perpetually emitted from millions of funs may be concerned in this fhining fluid, it might be prefumptuous to attempt to deteterinine; but, notwithstanding the unconceivable fubtilty of the particles of light, when the number of the emitting bodies is almost infinitely great, and the time of the continual emiffion indefinitely long, the quantity of emitted particles may well become adequate to the conftitution of a fhining fluid, or luminous matter, provided a caufe can be found that may retain them from flying off, or reunite them. But fuch a caufe cannot be difficult to guess at, when we know that light is fo easily reflected, refracted, inflected, and deflected;

and that, in the immenfe range of its courfe, it must pafs through innumerable fyftems, where it cannot but frequently meet with many obftacles to its rectilinear progreffion Not to mention the great counteraction of the united attractive force of whole fidereal fyftems, which must be continually exerting their power upon the particles while they are endeavouring to fly off. However, we fhall lay no ftrefs upon a furmife of this kind, as the means of verifying it are wanting: nor is it of any immediate confequence to us to know the origin of the luminous matter. Let it fuffice that its existence is rendered evident, by means of nebulous stars.

"I hope it will be found, that in what has been said I have not launched out into hypothetical reafonings; and that facts have all along been kept fufficiently in view. But, in order to give every one a fair opportunity to follow me in the reflections I have been led into, the place of every object from which I have argued has been purpofely added*, that the validity of what I have advanced might be put to the proof by those who are inclined, and furnifhed, with the neceffary inftruments to undertake an attentive and repeated infpection of the fame phæ

nomena.

W. HERSCHEL." Slough, Jan. 1, 1791.

For thefe places we must refer our readers to the eighty-firft volume of the Phis lofophical Tranfactions.

COMMU

1

COMMUNICATION from the COMMITTEE of COUNCIL appointed for the CONSIDERATION of all MATTERS relating to TRADE and FOREIGN PLANTAT ONS, to the ROYAL SOCIE TY, relative to the NATURAL HISTORY of AMBERGRIS.

"SIR,

"L

[From the fame work.]

ORD Hawkesbury, prefident of the committee of privy _council appointed for the confideration of all matters relating to trade and foreign plantations, having received a letter from Mr. Champion, a principal merchant concerned in the Southern Whale Fishery, informing him, that a fhip belonging to him had lately arrived from the faid fishery, which had brought home 362 ounces of ambergris, found by Mr. Coffin, captain of the faid fhip, in the body of a female fpermaceti whale, taken on the coaft of Guinea; his lordship thought fit to defire captain Coffin, as well as Mr. Champion, to attend the lords of the committee, that they might be examined concerning all the crcumstances of the fact before mentioned; and I am directed by their lordships to tranfmit to you a copy of the examination of these two gentlemen, that you may communicate the fame to the Royal Society, if you should think that any of the circumftances, stated in this examination, will contribute to remove the doubts hitherto entertained concerning the natural history and production of this valuable drug. I fend you alfo a piece of the ambergris fo taken out of the whale, and fome of the bills of the fifh called Squids (which are fuppofed to be the food of fperinaceti whales), and which were found

partly in the ambergris taken from this female whale, and partly on the outfide of it, and adhering to it.

"I have the honour to be, &c.
"W. FAWKENER.".

"At the council chamber, Whitehall, the 12th January, 1791.

"By the right honourable the lords of the committee of council appointed for the confideration of all matters relating to trade and foreign plantations.

"READ-Letter from Mr. Alex. ander Champion, a principal merchant concerned in the Southern Whale Fishery, to lord Hawkesbury, dated the 2d inftant, acquainting his lordship, that captain Joshua Coffin, of the ship the Lord Hawkefbury, is lately arrived from the Southern Whale Fishery; and that the faid fhip, befides a cargo of 76 tons of fpermaceti oil and head-matter, has brought home about 360 ounces of ambergris, which the faid captain took out of the body of a female fpermaceti whale on the coast of Guinea.

"Mefl. Champion and Coffin at-
tending, were then called in,
and the following questions
were put to Mr. Coffin, viz.
Q. Have any of the whales,

taken

« PreviousContinue »