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Optical Apprarances. if the united brightness of a neigh.

From this theoretical view of bouring cluster of stars fhould, in the heavens, which has been taken, a remarkable clear.night, reach his as we observed, from a point not fight, it will put on the appearance less distant in time than in space, of a small, faint, whitish, nebulous we will now retreat to our own re- cloud, not to be perceived without tired station in one of the planets, the greatest attention. To pats by attending a star in its great combi- other situations, let him be placed nation with numberless others; in a much extended Itratum, or and, in order to investigate what branching cluster of millions of will be the appearances from this stars, such as may fail under the contracted fituation, let us begin third form of nebulæ conlidered in with the naked eye.. The itars of a foregoing paragraph. Here also the first magnitude being in all pro- the heavens will not only be richly. bability the nearest, will furnish us scattered over with brilliant conwith a step to begin our scale ; fet- ftellations, but a fining zone or ting off, therefore, with the di- milky way will be perceived to surStance of Sirius or Arcturus, for round the whole sphere of the heainstance, as unity, we will at pre- vens, owing to the combined light sent luppose, that those of the fe. of thofe stars which are too small, cond magnitude are at double, and that is, too remote to be feen. Our those of the third at treble the di- observer's light will be so confined, stance, and so forth. It is not ne- that he will imagine this single col. cetary critically to examine what lection of stars, of which he does quantity of light or magnitude of not even perceive the thousandth a ttar intitles it to be estimated of part, to be the whole contents of fuch or such a proportional distance, the heavens. Allowing him now as the common coarte estimation the use of a common telescope, he will answer our present purpose as begins to fufpect that all the milkis well; taking it then for granted, neis of the bright path which fur. that a star of the seventh magni. rounds the sphere may be owing to tude is about seven times as far as stars. He perceires a few cluiters one of the firít, it follows, that an of them in various parts of the observer, who is inclosed in a glo- heavens, and finds also that there bular cluster of stars, and not far are a kind of nebulous patches; from the centre, will never be able, but still his views are not extended with the naked eye, to fee to the fo far as to reach to the end of the end of it; for, fince, according to ftratum in which he is fituated, to the above estimations, he can only that he looks upon these patches as extend his view to about seven belonging to that system which ta times the distance of Sirius, it can him Seems to comprehend every not be expected that his eyes should celestial object. He now increa es reach the borders of a cluster which his power of vision, and, applying has perhaps not less than fifty fars himself to a close observation, finds in depth every where around him. that the inilky way is indeed nu The whole universe, therefore, to other than a collection of very him will be comprised in a set of small stars. He perceives that thoie constellations, richly ornamented objects which are called nebulz'are with scattfred stars of all fizes. Or evidently nothing but clusters of

fars

stars. He finds their number in- firmed and established by a series of crease upon him, and when he re- observations. It will appear that folves one nebula iuto stars, he dif- many hundreds of nebulæ of the covers ten new ones which he can. first and second forms are actually not resolve. He then forins the to be seen in the heavens, and their idea of immense strata of fixed itars, places will hereafter be pointed out. till, going on with such interesting Many of the third form will be dea observations, he now perceives that scribed, and instances of the fourth all these appearances muit natu- related. A few of the cavitics mens rally arise from the confined fitua. tioned in the fifth will be particu. tion in which we are placed. Con- larised, though many more have fined it may justly be called, though already been observed; so that, in no less a space than what before upon the whole, I believe it will be appeared to be the whole region of found, that the foregoing theorethe fixed stars; but which now has tical view, with all its consequenaffumed the fhape of a crookedly tial appearances, as seen by an eye branching nebula ; not indeed one inclosed in one of the nebulæ, is of the least, but perhaps very far no other than a drawing froin nafrom being the most contiderable of ture, wherein the features of the these numberless clusters that enter original have been closely copied ; into the construction of the heavens. and I hope the resemblance will not

be called a bad one, when it hall Result of Observations.

be considered how very limited mult “ I shall now endeavour to shew, be the pencil of an inhabitant of so that the theoretical view of the small and retired a portion of an infyslem of the universe, which has definite fyftem in attempting the been exposed in the foregoing part picture of so unbounded an exof this paper, is perfectly conliltent

tent." with facts, and seemns to be con

DESCRIPTION of a NEW MARINE ANIMAL. In a LETTER

from Mr. EvERARD Home, Surgeon, to John HUNTER, Efq.F.R.S.

[From the fame Publication.)

" I

SENT you, about three years enquiries among the naturalists,

The specimen I badoes, which was unlike any one sent you was found on a part of the I had ever seen. From the want of coast which had undergone very rebooks and other information in that markable changes, in consequence illand, I was unable at the time to of a violent hurricane. These find out, whether it was a new ac- changes were indeed the means of quifition, or had been described by its being discovered, and present a any authors in natural history. probable reason why it was not dis

* Since my arrival in England, covered before. The extraordinary I have examined the libraries of circumttances which brought it fome men of science for an account within our reach, and the filence of this animal, and have made other of all the authors on natural hi. 2

Story

story which I have been able to long dead, or more probably deconsult, incline me to believe it to stroyed by the motion of the rocks be a non-defcript. As the pecu- in the storm : fome few of the liarities of its structure may add to brain-stones, however, that had been the knowledge of the natural hi- thrown beyond the reef, and lodg. story of other animals of this ge• ed in the shoal water, receiving less nus, at present fo little understood, injury, the animals were preserved I have drawn out a more particular unhurt. account of it ; which, if

you

think • The animal, with the shell, is it deserves attention, you may pre- almost intirely inclosed in the brainfent to the Royal Society.

1tone, so that at the depth in which “ This animal was found on the they generally lie, they are hardly fouth-east coast of Barbadoes, close discernible through the water from to Charles Fort, about a mile from the common surface of the brain. Bridge Town, in fome fhoal wa- stone; but when in search of food, ter, separated from the sea by the they throw up two cones, with ftones and sand thrown up by the membranes twiited round them in a dreadful hurricane, which happen- fpiral manner, which have a loose ed in the year 1780, and did fo fringed edge, looking at the botmuch mischief to the island. tom of the sea like two flowers;

“ The wind, in the beginning and in this state they were discoof the storm, which was in the af- vered. ternoon, blew very furioully from “ The species of Actinia, called the north-west, making a prodigi. in Barbadoes the animal flower, ous fwell in the sea ; and in the and common to many parts of that middle of the night changing fud- itland, although rarely before seen denly to the south-east, it blew from on this part of the coast, was now that quarter upon the sea, already found in confiderable numbers in agitated, forcing it upon the fhore this thoal water. with so much violence, that it threw « The animal was first observed down the rampart of Fort Charles, by captain Hendie, the officer comwhich was opposed to it, although manding Fort Charles, in looking thirty feet broad, by the bursting for shells which were thrown up of one fea. It forced up, at the in great numbers from the bottom fame time, immense quantities of of the harbour. He found a piece large coral rocks from the bottom of brain-stone containing three of of the bay, making a reef along them in different parts of it. Some this part of the coalt for the extent little time after, I was lucky enough of several miles, at only a few yards to find another brain-stone with distance from the shore.

two in it; one of them is the fpe6 The foundings of the harbour cimen in your poffeffion; the other were found afterwards to be intire- was destined for examination, of ly changed, by the quantity of ma- which the following is the account. terials removed from the bottom in 66 The animal, wlien taken out different places. In the reef of co- of the shell, including the two cones ral was found an infinite number of and their membranes, is five inches large pieces of brain ftone, con- in length; of which the body is taining the shell of this animal; three inches and three-quarters, but the animals had either been and the apparatus for catching its

prey,

1

1

grey, which may be considered as ment; but the upper and lower its tentacula, about an inch and a ends are lying loote. quarter.

“ From the end of the body, “ The body of the animal is at. between the two upper ends of tached to its shell, for about three. these cartilages, arise what I lupquarters of an inch in length, at pofe to be the tentacula, confitting the anterior part where the two of two cones, each having a spiral cones arise, by means of two car- membrane twining round it: they tilaginous fubitances, with one tide are close to each other at their adapted to the body of the animal, bases, and diverge as they rise up, the other to the internal surface of being about an inch and a quarter the shell: the rest of the body is in length, and nearly one-lixth of unattached, of a darkish white co- an inch in thickness at their base, lour, about half an inch brdad, a and gradually diminishing till they little Hattened, and rather narrow- terminate in points.

The memer towards the tail. The muscular branes which twine round these fibres upon its back are transverse; cones also take their origin from those on the belly longitudinal, the body of the animal, and make making a band the whole length of five spiral turns and a half round the body, on the edge of which the each, being lost in the points of the transverse fibres running across the cones ; they are loote from the back terminate.

cone at the lowest spiral turn which “ The two cartilaginous fub- they make, and are nearly half an stances by which the animal ad- inch in breadth; they are exceedheres to its shell, are placed one on ingly delicate, and have at small cach fide of the body, and are distances fibres running across them joined together upon the back of from their attachment at the stem the animal at their pofterior edges : to the loose edge, which gives them they are about three quarters of an a ribbed appearance. These fibres inch long, are very narrow at their are continued about one-tenth of anterior end, becoming broader as an inch beyond the membrane, have they go backwards ; and at their ing their edges finely serrated, like polierior end they are the whole the tentacula of the Actiniæ found breadth of the body of the animal. in Barbadoes: these tentacula shortUpon their external surface there en as the spiral turns become smallare fix transverse ridges, or nar- er, and are entirely lost in that part row folds ; and along their exter- of the membrane which terminates nal edges, at the end or termina- in the point of the cone. tion of each ridge, is a little emni. . " Behind the origin of these nence refembling the point of a cones arises a small thell, which, hair pencil, so that on each side of for one fixth of an inch from its the animal there are fix of these attachment to the animal, is very little projecting ituds, for the pur- slender : it is about three-quarters pose of adhering to the fides of the of an inch in length, becoming Thell in which the animal is incloso considerably broader at the other ed. The internal surfaces of these end, which is Hat, and about onecartilages are firmly attached to the third of an inch broad; the flatbody of the animal, in their mid. tened extremity is covered with a dle part, by a kind of band or liga kind of hair, and has riting out of it two finall claws, about one-sixth « The animal, when at reft, is of an inch in length. If the hair, wholly concealed in its shell; but and mucus entangled in ir, be taken when it seeks for food, the move. away, this extremity of the Mell able thell is puthed flowly out with becomes concave, is of a piuk co- the cones and their membranes in a lour, and the two claws riding out collapsed state ; and when the whole from its middle part have each is exposed, the moveable shiell falls three short branchei, not unlike the à litile back, and the membrane horns of a deer. The body of this round each of the cones is expandThell has a soft cartilaginous cover- ed, the tentacula at the bates of ing, with an irregular but polithed the cones having jutt room enough surface: on this the cones rest in to move without touching one antheir collapsed fate, in which state other. The thin inembrane which the whole of the shell is drawn into lays between the cones and the inthe cavity of the brain-stone, ex- cloting shell is protruded in the cepting the flattened end with the furin of a fold, and lies over the two claws.

external shell which projects froin 6. Before the cones there is a thin the brain-stone. membrane, which appears to be of 6 The membranes hare a flow the fame length with the shell just spiral motion, which continues duro described. In the collapsed state it ing the whole time of their being lies between the cones and the thell expanded ; and the tentacula upon in which the animal is inclosed; their edges are in constant action. but when the tentacula are thrown The motion of the membrane of out, it is also protruded.

the one cone seems to be a little “ The Mell of this animal is a different from that of the other, tube, which is very thin, and adapt- and they change from the one kind ed to its body: the internal tửrface of motion to the other alternately, is smooth, and of a pinkish white a variation in the colour of the mem. colour : its outer surface is covered brane at the same time taking place, by the brain-itone in which it is in. either becoming a shade lighter or closed, and the turnings and wind. darker; and this change in the coings which it makes are very nume. lour, while the whole is in motion,

The end of the shell, which produces a pleasing effect, and is opens externally, rises above the most striking when the sun is very surface of the lone on one side half bright. The membranes, howerei, an inch in height, for about half at some particular times appear 10 the circumference of the aperture, be of the same colour. bending a little forwards over it, 6. While the membranes are in and becoming narrower and nar. motion, a little mucus is often les rower as it goes up, terminating at parated from the tentacula at the last in a point just over the centre point of the cone. Upon the lealt of the opening of the thell: on motion being given to the water, the other side it forms a round mar- the cones are immediately and very gin to the surface of the brain-stone, fuddenly drawn in. This part of the shell is much thick. “ This apparatus for catching er and stronger than that part which food is the molt delicate and com. is inclosed in the brain-stone: its plicated that I have seen ; but I thall outer surface is of a darkish brown not trouble you with any conjec: colour; its inner of a pinkish white, tures upon what that food may be, as

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