thousand paces; in breadth it could scarcely exceed a hundred. It is difficult to conceive how so prodigious a number of these voracious insects can find sufficient nourishment, in so naked a country, till they arrive at maturity; since we must take it for granted that the number of the larvæ greatly exceeds that of the perfect animal. Probably sudden prolific showers, which for a while renew vegetation, may at the same time assist the hatching of the eggs, and the developement of the young larvæ; yet this supposition is not a little contradicted by the observation that such swarms are seen at all times of the year, even after a long and general drought, and in countries the most bare of vegetation. On my first journey I once found in the lower Bokkeveld a whole field strewed over with the larva of another sort of insect: they sat by hundreds on a bush, gnawing the rind, and the woody fibres; every thing around was devoured, and nothing was to be seen which appeared capable of affording subsistence to these creatures: it was evident that they must have been hatched upon the spot. We may therefore presume that the eggs are hatched very suddenly, and that the young animals require little nourishment; that it is not till they become perfect, at the time when vegetation becomes more abundant, that their extreme voracity commences. The locusts of southern Africa have hitherto been supposed the same as those which infest Asia and some of the southeasterly parts of Europe, gryllus tataricus; but on the examination VOL. LVII. of some specimens which I preserved, they are determined to be a very different species, and they now bear their appropriate nume of Gryllus devastator. GIRAFFE. (From the Same.) We had scarcely travelled an hour, when the Hottentots called our attention to some object on a hill not far off on the left hand, which seemed to move. The head of something appeared almost immediately after, feeding on the other side of the hill; and it was concluded that it must be that of a very large animal: this was confirmed, when, after going scarcely a hundred steps farther, two tall swan-necked giraffes stood almost directly before us. Our transports were indescribable, particularly as the creatures themselves did not perceive us, and therefore gave us full time to examine them, and to prepare for an earnest and serious chace. The one was smaller, and of a paler colour than the other, which Vischer immediately pronounced to be a colt, the child of the larger. Our horses were saddled, and our guns loaded in an instant, when the chace commenced. Since all the wild animals of Africa run against the wind, so that we were pretty well assured which way the course of these objects of our ardent wishes would be directed, Vischer, as the most experienced hunter, separated himself from us; and, by a circuit, took the animals in front, that he might stop their 2 K way, way, while I was to attack them in the rear. I had almost got within shot of them, when they perceived me, and began to fly in the directiou we expected. But their flight was so beyond all idea extraordinary, that between laughter, astonishment, and delight, I almost forgot my designs upon the harmless creatures' lives. From the extravagant disproportion between the height of the fore to that of the hinder parts, and of the height to the length of the animal, great obstacles are presented to its moving with any degree of swiftness. When Le Vaillant asserts that he has seen the giraffe trot, he spares me any farther trouble in proving that this animal never presented itself alive before him. How in the world should an animal, so disproportioned in height, before and behind, trot? The giraffe can only gallop, as I can affirm from my own experience, having seen between forty and fifty at different times, both in the power of the muscles alone; he must bend back his long neck, by which the centre of gravity is thrown somewhat more behind, so as to assist his march; then alone it is possible for him to raise his fore-legs from the ground. The neck is however thrown back without being itself bent, it remains stiff and erect, and moves in this erect form slowly backwards and forwards with the motion of the legs, almost like the motion of a ship dancing upon the waves, or, according to the phrase used by the sailors, a reeling-ship. It is not difficult to overtake the giraffe with a tolerably good horse, especially if the ground be advantageous, and somewhat on the rise; for it will be easily comprehended that it must be extremely difficult for a creature of such a structure to move upon the ascent. PITCH WELLS. Ionian Isles, &c. their slow and hasty movement, (From Dr. Holland's Travels in the) for they only step when they are feeding quietly. But this gallop is so heavy and unwieldy, and seems performed with so much labour, that in a distance of more than a hundred paces, comparing the ground cleared, with the size of the animal, and of the surrounding objects, it might almost be said that a man goes faster on foot, The heaviness of the movement is only compensated by the length of the steps, each one of which clears on a moderate computation, from twelve to sixteen On account of the size and weight of the foreparts, the giraffe cannot move forwards through feet. The pitch wells of Zante are a natural phenomenon, which may be regarded as among the antiquities of the isle; since they were known and described as early as the time of Herodotus, and are mentioned since by Pausanias, Pliny, and other authors. They are situated about ten miles from the city, and near the shore of the bay, on the southern side of the island. We visited this spot, which is called Chieri, a day or two after our arrival in Zante. A small tract of marshy land, stretching down to the sea, and surrounded on of limestone, or a bituminous shale, is the immediate situation of the springs; they are found in three or four different places of the morass, appearing as small pools; the sides and bottom of which are thickly lined with petroleum, in a viscid state, and, by agitation, easily raised in large flakes to the surface. The most remarkable of these pools is one circular in form, about fifty feet in circumference, and a few feet in depth, in which the petroleum has accumulated to a considerable quantity. The water of the spring, which is doubtless the means of conveying the mineral upwards to the surface, forms a small stream from the pool, sensibly impregnated with bituminous matter, which it deposits in parts as it flows through the morass; the other pools are of similar character. The petroleum is collected generally once in the year; and the average quantity obtained from the springs is said to be about a hundred barrels; it is chiefly used for the caulking of vessels, not being found to answer equally well for cordage. on other sides by low eminences tion, and lassitude and uneasiness in the limbs. Those who are strongly susceptible to electrical changes in the air, such as precede and attend a thunder-storm, will easily understand the effects of the Sirocco, as an increased degree of the sensations which they then experience; and, in fact, though I am not aware that the opinion has been held, there are many reasons for believing that the peculiarity of the Sirocco wind is chiefly an electrical one, and not depending either on temperature, an undue proportion of carbonic acid, the presence of minute particles of sand, or any of the causes which have been generally assigned to it. That increased temperature is not the cause, may be inferred from the thermometer being little, if at all, raised by the access of the wind, and from much greater heat often occurring without this singularity of effect. The air of the Sirocco, as it comes from the sea, is not a dry one, but in general thick, and loaded with moisture; much of which appears to be deposited where it passes over any considerable extent of land. I have scarcely, in any instance, observed this wind, in any marked degree, without noticing, at the same time, some electrical phenomena in connection with it; to say nothing of the effects upon the body, which, as mere sensations, may perhaps be doubtfully received in evidence. In the present instance, off the coast of Ithaca, the sky, which had been obscured by the approach of evening, was suddenly kindled, as the wind came on, by broad flashes or gleams of electric light, which seemed to prevade the whole 2 K 2 hemisphere, THE SIROCCO. (From the Same.) A sudden and violent Sirocco came on from the south-east, carrying our vessel forwards eight or ten miles an hour; but bringing with it, at the same time, all the distressing effects which characterize this extraordinary wind; a sense of general oppression, a dull head-ache, aversion to mo hemisphere, and, at intervals, were so bright as to allow the reading of the smallest print. At the same time I observed a mass of clouds gathering in the northwest, the quarter to which the wind was blowing, and here the electrical appearances became peculiarly vivid, flashes of light shifting rapidly among the broken intervals of the clouds, and near the horizon, assuming at times the appearance of a chain of light, which seemed to pass from a higher to a lower surface of cloud, and often continued to the eye for two or three seconds. USEFUL USEFUL PROJECTS, &c. Sir Humphrey Davy's Discovery of a Method for preventing Explosions from the Fire Damp in Mines. It is evident, then, that to prevent explosions in coal mines, it is only necessary to use air-tight lanterns, supplied with air from tubes or canals of small diameter, or from HE numerous fatal effects of apertures covered with wire gauze which have lately engaged the public attention, having induced the eminent chemical philosopher above-mentioned to turn his studies to the subject, the result has been a very curious and valuable paper communicated to the Royal Society, and printed in their Transactions for 1815, from which the following extract, chiefly referring to the practical part, has been made. After ascertaining, by a variety of experiments, the combustibility and explosive nature of the fire-damp in mines, and finding that a mixture of this gas with air would not explode in metallic canals or troughs when their diameter was less than one-seventh of an inch, and that explosions would not pass through such canals; also that explosions would not pass through very fine wire sieves or wire gauze; Sir H. D. comes to the following inference. which explosions cannot be communicated, and having a chimney at the upper part, on a similar system for carrying off the foul air; and common lanterns may be easily adapted to the purpose, by being made air-tight in the door and sides, by being furnished with the chimney, and the system of safety apertures below and above. The principle being known, it is easy to adopt and multiply practical applications of it. The first safe-lantern that I had constructed was made of tin-plate, and the light emitted through four glass plates in the sides. The air was admitted round the bottom of the flame from a number of metallic tubes of of an inch in dia18 meter, and an inch and long.The chimney was composed of two open cones, having a common base perforated with many small apertures, and fastened to the |