natural debility of old age of trees and of animals ginate from a similar source?"

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Observations upon luminous Animals. By Mr. MACARTNEY.

THE Zoophite is the most splendid of the luminous inhabit ants of the ocean. The flashes of light emitted during its contractions are so vivid as to affect the sight of the spectator. The luminous state of the sea between the tropics is generally accompanied with the appearance of a great number of marine animals, of various kinds, upon the surface of the water. In the Arabian Sea have been seen several luminous spots in the water, and when the animals, supposed to be the cause of them, were examined, they were found to be insects about the third of an inch in length, resembling in appearance the wood-louse. The insect, when viewed with the microscope, 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.

He notices many others that have from time to time come under his inspection: one of these, which he denominates the beroe fulgens, is a very elegant creature, changing its colour between purple, violet, and pale blue: the body is truncated before and pointed behind; but the exact form is difficult to assign, as it is varied by particular contractions at the animal's pleasure. When this insect 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 several 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. Mr. Macartney, having noticed many other species, says, that his own observations lead him to conclude, that the medusa scintillans is the most frequent source of light of the sea round this country, and likewise in other parts of the world.

We are next informed, that the remarkable property of emitting light during life, is only met with among animals of the four last classes of modern naturalists, viz. mollusca, insects, worms, and zoophytes. The mollusca and worms contain each but a single species; the pholas dactylus in the one, and nereis noctiluca in the other. Some species yield light in the

eight following genera of insects, viz. elater, lampyris, fulgora, paussus, scolopendra, cancer, lynceus, and limulus. The luminous species of the genera lampyris and fulgora are more numerous than is generally supposed. Among the zoophytes, the genera medusa, beroe, and pennatula, contain species which afford light. The only animals that appear to possess a distinct organization for the production of light, are the luminous species of lampyris, elater, fulgora, and paussus.

The light of the lampyrides proceeds from some of the last rings of the abdomen, which, when not illuminated, are of å yellow colour. The number of luminous rings varies in different species, and, as it seems, at different periods in the same individual. Besides this luminous substance there are, in the common glow-worm, on the inner side of the last abdominal ring, two bodies, which to the naked eye appear more minute than the head of the smallest pin. They are lodged in two slight depressions, formed in the shell of the ring, which is at these points particularly transparent. These, when examined, were found to be sacs, and contain a soft yellow substance. The light that proceeds from these sacs is less under the control of the insect than that of the luminous substance spread on the rings: it is seldom entirely extinguished in the season that the glow-worm gives light, even during the day; and when all the other rings are dark, these sacs often shine brightly. In all the dissections made by Mr. Marcartney of luminous insects, he did not find that the organs of light were better, or differently supplied with either nerves or air-tubes, than other parts of the body. The power of emitting light likewise exists in some creatures which want nerves; a circumstance that strongly marks the difference between animal light and animal electricity. In general, the exhibition of light, in animals, depends upon the presence of a fluid matter, which in some instances is confined to particular parts of the body, and in others is diffused throughout the whole substance of the animal.

The property of emitting light is confined to animals of the simplest organization, the greater number of which are inhabitants of the sea. The luminous property is not constant, but in general exists only in certain periods in particular states of the animal body. The power of showing light resides in a particular substance, or fluid, which is sometimes situated in a particular organ, and in others diffused throughout the animal's body. The light is differently regulated when the luminous matter exists in the living body, and when it is abstracted from it. In the first case it is intermitting

with periods of darkness, is commonly produced or increased by a muscular effort, and is sometimes absolutely dependent upon the will of the animal. In the second case, the luminous appearance is usually permanent, until it becomes extinct, after which it may be restored directly by friction, concussion, and the application of warmth, which last causes operate on the luminous matter only indirectly by exciting the animal.

The luminous matter, in all situations, is incombustible, and loses the quality of emitting light by being dried, or much heated. The exhibition of light, however long it may be continued, causes no diminution of the bulk of the luminous matter. It does not require the presence of pure air, and is not extinguished by other gases. The luminous appearance of living animals is not exhausted by long continuance, or fre quent repetitions, nor accumulated by exposure to natural light: it is therefore not dependent upon any foreign source, but inheres as a property, in a peculiarly organized animal substance, or fluid, and is regulated by the same laws which govern all other functions of living beings. The light of the sea is always produced by living animals, and most frequently by the presence of the medusa scintillans. When great numbers of this species approach the surface, they sometimes coalesce, and cause that snowy or milky appearance of the sea, which is so alarming to navigators. These animals, when congregated on the surface of the water, can produce a flash of light like an electric corruscation. The luminous property does not ap pear to have any connection with the economy of the animals that possess it, except in flying insects, which by that means discover each other at night, for the purpose of sexual

congress.

Account of a Vegetable Wax from Brazil. By W. T. BRANDE

THE vegetable wax described in this paper is said to be the production of a tree of slow growth, called by the natives Carnauba, which produces a gum used as food for man, and another substance employed for fattening poultry. If this article can be procured in abundance, it may become a valuable addition to the comforts of mankind, by reduc ing the price and improving the quality of candles, flambeaux, &c.

The wax, in its rough state, is in the form of a coarse grey powder, soft to the touch, and mixed with various impurities, which, when separated by a sieve, amount to about 40 per

cent. It has an agreeable odour, somewhat resembling new hay, but scarcely any taste.

At 206 of Fahr. it enters into perfect fusion, and may then be further purified by passing it through fine linen: it then acquires a dirty-green colour, and its peculiar smell becomes more evident. When cold, it is moderately hard and brittle its specific gravity is 980.

Although the vegetable wax possesses the characteristic properties of bees'-wax, it differs from that substance in many of its chemical habitudes. It also differs from the other varieties of wax; namely, the wax of the myrica cerifera, of lac, and of white lac.

Perhaps the most important part of the present enquiry is that which relates to the combustion of this wax in the form of candles. The trials which have been made to ascertain its fitness for this purpose are very satisfactory. The addition, it appears, of from one-eighth to one-tenth part of tallow is sufficient to obviate the brittleness of the wax in its pure state, without producing any unpleasant effect.

Narrative of the Eruption of a Volcano in the Sea off the Island of St. Michael. By S. TILLARD, Esq. Captain in the Royal Navy. — [1812.]

APPROACHING the island of St. Michael, on Sunday the 12th of June, 1811, in his Majesty's sloop Sabrina, under my command, we occasionally observed, rising in the horizon, two or three columns of smoke, such as would have been occasioned by an action between two ships, to which cause we universally attributed its origin. This opinion was, however, in a very short time changed, from the smoke increas ing and ascending in much larger bodies than could possibly have been produced by such an event; and having heard an account, prior to our sailing from Lisbon, that in the preceding January or February a volcano had burst out within the sea near St. Michael's, we immediately concluded that the smoke we saw proceeded from that cause, and, on our anchoring the next morning in the road of Ponta del Gada, we found this conjecture correct as to the cause, but not to the time; the eruption of January having totally subsided, and the present one having only burst forth two days prior to our approach, and about three miles distant from the one before alluded to.

Desirous of examining as minutely as possible a contention so extraordinary between two such powerful elements, I set

off from the city of Ponta del Gada on the morning of the 14th, in company with Mr. Read, the consul general of the Azores, and two other gentlemen. After riding about twenty miles across the N.W. end of the island of St. Michael's, we came to the edge of a cliff, from whence the volcano burst suddenly upon our view in the most terrific and awful grandeur. It was only a short mile from the base of the cliff, which was nearly perpendicular, and formed the margin of the sea; this cliff being, as nearly as I could judge, from three to four hundred feet high. To give you an adequate idea of the scene by description is far beyond my powers; but for your satisfaction I shall attempt it.

Imagine an immense body of smoke rising from the sea, the surface of which was marked by the silvery rippling of the waves, occasioned by the light and steady breezes incidental to those climates in summer. In a quiescent state, it had the appearance of a circular cloud revolving on the water like an horizontal wheel, in various and irregular involutions, expanding itself gradually on the lee side, when suddenly a column of the blackest cinders, ashes, and stones, would shoot up in form of a spire at an angle of from ten to twenty degrees from a perpendicular line, the angle of inclination being universally to windward; this was rapidly succeeded by a second, third, and fourth, each acquiring greater velocity, and overtopping the other, till they had attained an altitude as much above the level of our eye, as the sea was below it.

As the impetus with which the columns were severally propelled diminished, and their ascending motion had nearly ceased, they broke into various branches resembling a group of pines; these again, forming themselves into festoons of white feathery smoke in the most fanciful manner imaginable, intermixed with the finest particles of falling ashes, which at one time assumed the appearance of innumerable plumes of black and white ostrich feathers surmounting each other; at another, that of the light wavy branches of a weeping willow.

During these bursts, the most vivid flashes of lightning continually issued from the densest part of the volcano; and the cloud of smoke, now ascending to an altitude much above the highest point to which the ashes were projected, rolled aff in large masses of fleecy clouds, gradually expanding themselves before the wind in a direction nearly horizontal, and drawing up to them a quantity of water-spouts, which formed a most beautiful and striking addition to the general appearance of the scene.