their kitchens and cellars in general, though they were well acquainted with the injurious qualities of oxide of copper taken internally. This oxide however they used externally for cleansing and healing wounds. According to Aristotle, wounds made with weapons of bronze were more easily cured than those made with weapons of iron.

"In a note subjoined Mr. Darcet observes, that the metal of the horses of the Carrousel, taken as it is, yields copper, tin, lead, gold, and silver. If the surface be filed, so as to remove all the gilt part, nothing is found but copper, tin, and lead. If a piece perfectly free from cracks be taken, and thoroughly cleaned by the file, it yields copper and tin alone: but it is difficult to

procure such pieces, for the copper is full of flaws, and the mixture of lead and tin, with which the horses were, partly filled, has insinuated itself into every crack. On analys ing some select pieces, he found copper 99.177, tin 0823: but as sulphuric acid disturbed the transparency of the solution, he supposes a little lead was present, and that part of the tin might come from the alloy of tin and lead, which had covered the inside of the pieces he used.

"He could not procure a piece well gilt, to examine in what way the gold was applied; but he observes that the brittleness of the metal seems to indicate, that quicksilver was employed."

“THE

HE property which certain animals possess of emitting light, is so curious and interesting, that it has attracted the attention of naturalists in all ages. It was particularly noticed by Aristotle and Pliny amongst the ancients, and the publications of the different learned societies in Europe, contain numerous memoirs upon the subject. Notwithstanding the degree of regard bestowed upon the history of luminous animals, it is still very im perfect; the power of producing light appears to have been attributed to several creatures which do not possess it; some species which enjoy it in an eminent degree, have been imperfectly described, or entirely unobserved; the organs which afford the light in certain animals

have not been examined by dissection; and lastly, the explanations that have been given of the phænomena of animal light, are unsatis factory, and in some instances palpably erroneous.

As this subject forms an inte resting part of the history of organized beings, I have for some years availed myself of such op. portunities as occurred for its investigation. Having communicated the result of some of my researches to the Right Honourable Sir Joseph Banks, he immediately offered me his assistance with that liberality, which so eminently distinguishes him as a real lover of science. I am indebted to him for an inspection of the valuable journal he kept during his voyage with Captain Cook; for

permission

permission to copy the original draw ings in his possession, of those luminous animals discovered in both the voyages of Cook; and for some notes upon the luminous appearance of the sea, that were presented to him by Captain Horsburg, whose accuracy of observation is already known to this learned Society.

"In the following paper, I shall first examine the grounds on which the property of shewing light has been ascribed to certain animals, that either do not possess it, or in which its existence is questionable. I shall next give an account of some luminous species, of which some have been inaccurately described, and others quite unknown. I shall endeavour to explain from my own observations, and the information communicated to me by others, many of the circumstances attending the luminous appearance of the sea. I shall then describe the organs employed for the production of light in certain species; and, lastly, I shall review the opinions which have been entertained respecting the nature and origin of animal light, and relate the experiments I have made for the purpose of elucidating this part of the subject.

"The property of emitting light has been reported to belong to several fishes, more particularly the mackarel, the moon-fish (tetraodon mola), the dorado, mullet, sprat, &c.

"Mr. Bajon observed during the migration of the dorados, &c. that their bodies were covered with luminous points. These, however, proved, upon examination, to be minute spherical particles, that adhered to the surface of these fishes; and, he adds, appeared to be precisely the same sort of points that

illuminated the whole of the sea at the time. They were, therefore, in all probability, the minute kind of medusa, which I shall have occasion to describe hereafter.

"Godeheu de Riville states, in a paper sent to the Academy of Sciences at Paris, that on opening the scomber pelamis while alive, he found in different parts of its body an oil which gave out much light: but it should be observed, that Riville had a particular theory to support, for which this fact was very convenient, and that other parts of his memoir bear marks of inaccuracy. It may be added, that if the oil of fishes were usually luminous, which Riville supposed, it would be almost universally known, instead of resting on a solitary observation.

"As far as I am able to determine from what I have seen, the faculty of exbibiting light during life does not belong to the class of fishes. It appears probable, that' some fishes may have acquired the character of being luminous, from evolving light soon after death.

"Some species of lepas, murex, and chama, and some star-fish, have been said to possess the power of shining; and the assertion has been repeated by one writer after anoth. r, but without quoting any authority.

Brugueire, upon one occasion, saw, as he supposed, common earth worms in a luminous state; all the hedges were filled with them; he remarked that the light resided principally in the posterior part of the body.*

"Flaugergues pretended to have seen earth-worms luminous in three instances; it was at each time in October; the body shone at every part, but most brilliantly at the genital organs.t

† Journal de Physique, Tom. XVI.

"Notwithstanding

Notwithstanding this concur rence of testimony, it is next to impossible that animals so frequently before our eyes as the common earthworm, should be endowed with so remarkable a property, without every person having observed it. If they only enjoyed it during the season for copulation, still it could not have escaped notice, as these creatures are usually found joined together in the most frequented paths, and in gar, den walks.

"In different systems of natural history, the property of shining is attributed to the cancer pulex. The authorities for this opinion are Hablitzl, and Thules and Bernard. The former observed, upon one occasion, a cable that was drawn up from the sea exhibit light, which upon closer inspection, was perceived to be covered by these insects.* Thules and Bernard reported that they met with a number of this species of cancer on the borders of a river, entirely luminous. I am nevertheless disposed to question the luminous property of the cancer pulex, as I have often had the animal in my possession, and never perceived it emit any light.

"The account given by Linneus of the scolopendra phosphorea, is so improbable and inconsistent, that one might be led to doubt this insect's existence, particularly as it does not appear to have been ever seen, except by Ekeberg, the captain of an East Indiaman, from whom Liuneus learnt its history.

"I now proceed to the description of those luminous animals that have been discovered by the Right Honourable Sir Joseph Banks, Captain Horsburg, and myself.

"On the passage from Madeira

to Rio de Janeiro, the sea was ob served by Sir Joseph Banks to be un. usually luminous, flashing in many parts like lightning. He directed some of the water to be hauled up, in which he discovered two kinds of animals that occasioned the phænomenon; the one, a crustaceous in sect, which he called the cancer fulgens; the other, a large species of medusa, to which he gave the name of pellucens.

The cancer fulgens bears some resemblance to the common shrimp; it is however considerably less, the legs are furnished with numerous setæ. The light of this animal, which is very brillant, appears to issue from every part of the body.

"The medusa pellucens measures about six inches across the crown or umbella; this part is marked by a number of opake lines, that pass off from the center to the circumfer rènce. The edge of the umbella is divided into lubules, which succeed each other, one large and two smail ones alternately. From within the margin of the umbella, there are suspended a number of long cordshaped tentacula. The central part of the animal is opake, and furnished with four thick irregularly shaped processes, which hang down in the midst of the tentacula.

"This zoophyte is the most splendid of the luminous inhabitants of the ocean. The flashes of light emitted during its contractions are so vivid, as to affect the sight of the spectator.

"In the notes communicated to Sir Joseph Banks by Captain Horsburg, he remarks, that the luminous state of the sea between the tropics is generally accompanied with the appearance of a great number of ma

Біде

rine animals of various kinds upon the surface of the water: to many of which he does not, however, attribute the property of shining. At other times, when the water which gave out light was examined, it appeared only to contain small particles of a dusky straw colour, which dissolved with the slightest touch of the finger. He likewise observes, that in Bombay, during the hot weather of May and June, he has frequently seen the edges of the sea much illuminated by minute spark ling points.

"At sun-rise on April 12, 1798, in the Arabian sea, he perceived several luminous spots in the water, which conceiving to be animals, he went in the boat and caught one. It proved to be an insect somewhat re. sembling in appearance the wood louse, and was about one third of an inch in length. When viewed with the microscope, it seemed to be formed by sections of a thin crustaceous substance. During the time that any fluid remained in the animal, it shone brilliantly like the fire fly.

"In the month of June in the same year, he picked up another Juminous insect on a sandy beach, which was also covered with a thin shell, but it was a different shape, and a larger size, than the animal taken in the Arabian sea.

"By comparing the above description with an elegant pen and ink drawing which was made by Captain Horsburg, and accompanied his paper, I have no doubt that both these insects were monoculi; the first evidently belongs to the genus limulus of Muller; I shall therefore beg leave to distinguish it by the name of limulus poctilucus.

"My pursuits, and the state of my health, having frequently led me to the coast, I have had many op

portunities of making observations upon the animals which illuminate our own seas. Of these I have discovered three species; one of which is a beroe not hitherto described by authors; another agrees so nearly with the medusa hemispherica, that I conceive it to be the same, or at least a variety of that species; the third is a minute species of medusa, which I believe to be the luminous animal so frequently seen by navi gators, although it has never been distinctly examined or described.

"I first met with these animals in the month of October 1804, at Herne Bay, a small watering place upon the northern coast of Kent, Having observed the sea to be extremely luminous for several nights, I had a considerable quantity of the water taken up. When perfectly at rest, no light was emitted, but on the slightest agitation of the vessel in which the water was contained, a brilliant scintillation was perceiv ed, particularly towards the surface; and when the vessel was suddenly struck, a flash of light issued from the top of the water, in consequence of so many points shining at the same moment. When any of these sparkling points were removed from the water, they no longer yielded any light. They were so transparent, that in the air they appeared like globules of water. They were more minute than the head of the smallest pin. Upon the slightest touch, they broke and vanished from the sight. Having strained a quantity of the luminous water, a great number of these transparent corpuscles were obtained upon the cloth, and the water which had been strained, did not afterwards exhibit the least light. I then put some sea-water that had been rendered particularly clear, by repeated filtrations, into a large glass, and baving

floated

floated in it a fine cloth, on which I had previously collected a number of luminous points, several of them were liberated, and became distinctly visible in their natural element, by placing the glass before a piece of dark coloured paper. They were observed to have a tendency to come to the surface of the water; and after the glass was set by for some time, they were found congregated cogether, and when thus collected in a body, they had a dusky straw colour, although individually they were so transparent, as to be perfectly invisible, except under particular circumstances. Their substance was indeed so extremely tender and delicate, that they did not become opaque in distilled vinegar or alcohol, until immersed in these liquors for a considerable time.

"On examining these minute globules with the microscope, I found that they were not quite perfect spheres, but had an irregular depression on one side, which was formed of an opaque substance, that projected a little way inwards, producing such an appearance as would arise from tying the neck of a round bag, and turning it into the body.

"The motions of these creatures in the water were slow and graceful, and not accompanied by any visible contraction of their bodies. After death they always subsided to the bottom of the vessel.

"From the sparkling light afforded by this species, I shall distinguish it by the name of medusa scintillans.

"The night following that, on which I discovered the preceding animal, I caught the two other luminous species. One of these I shall call the beroe fulgens.

"This most elegant creature is of a colour changing between purple, violet, and pale blue; the body is

truncated before, and pointed behind; but the form is difficult to assign, as it is varied by partial contractions, at the animal's pleasure. I have represented the two extremes of form that I have seen this creature assume: the first is somewhat that of a cucumber, which, as being the one it takes when at rest, should perhaps be considered as its proper shape: the other resembles a pear, and is the figure it has in the most contracted state. The body is hollow, or forms internally an infundibular cavity, which has a wide opening before, and appears also to have a small aperture, posteriorly through which it discharges its excrement. The posterior two-thirds of the body are ornamented with eight longitudinal ciliated ribs, the processes of which are kept in such a rapid rotatory motion, while the animal is swimming, that they appear like the continual passage of a fluid along the ribs. The ciliated ribs have been described by Professor Mitchell as arteries, in a luminous beroe, which I suspect was no other than the species I am now giving an account of.

When the beroe fulgens swam gently near the surface of the water, its whole body became occasionally illuminated in a slight degree; during its contractions, a stronger light issued from the ribs, and when a sudden shock was communicated to the water, in which several of these animals were placed, a vivid flash was thrown out. If the body were broken, the fragments continued luminous for some seconds, and being rubbed on the hand, left a light like that of phosphorus: this, however, as well as every other mode of emitting light, ceased after the death of the animal.

"The hemispherical species that I discovered, had a very faint purple