seventy-six miles, the variation appeared by several azimuths to be 16° 30′ West. SECTION II. The Passage from Madeira to Rio de Janeiro, with some Account of the Country, and the Incidents that happened there. On the 21st of September we saw the islands called the Salvages, to the north of the Canaries; when the principal of these bore S. W. at the distance of about five leagues, we found the variation of the compass by an azimuth to be 17° 50. I make these islands to lie in latitude 30° 11' north, and distant fifty-eight leagues from Funchiale in Madeira, in the direction of S. 16° E. On Friday the 23d we saw the Peak of Teneriffe bearing W. by S. S. and found the variation of the compass to be from 17° 22′ to 16° 30'. The height of this mountain, from which I took a new departure, was determined by Dr Heberden, who has been upon it, to be 15,396 feet, which is but 148 yards less than three miles, reckoning the mile at 1760 yards. Its appearance at sunset was very striking; when 'It is not said by what means Dr H. ascertained the height of this peak, and one may safely call in question his accuracy. In the table referred to in a former note, its height, as measured by the barometer, is stated to be 12,358 English feet, being nearly 10,000 feet lower than that of Chimborazo, the highest summit of the Andes, which is estimated at 21,440. But there is a good deal of contrariety in the statements of the heights of mountains. The following quotations from Krusenstern's ac count of his voyage will both prove this, and at the same time give the reader some lively conception of the magnificent effect of the Peak." At half past six in the morning, we distinctly saw the island of Teneriffe, and at seven the pic cleared itself of the clouds in which it had been enveloped until then, and appeared to us in all its majestic grandeur. As its summit was covered with snow, and was extremely brilliant from the reflection of the sun, this contributed very much to the beauty of the scene. On either side, to the east and west, the mountains, which nature seems to have destined to sustain this enormous mass, appeared gradually to decine. Every one of the mountains which surround the pie, would be considerable in itself; but their height scarcely attracts the attention of the beholder, although they contribute to diminish the apparent size of the pic, which, if it stood alone, would be much more striking, "At six the next morning, (this was the second morning after leaving Teneriffe) we still saw the pic from the deck; it bore by compass, N.E. 15° 30', that is, allowing for the variation, which is here 16° W.; N.W. 0° 30. At when the sun was below the horizon, and the rest of the island appeared of a deep black, the mountain still reflected his rays, and glowed with a warmth of colour which no painting can express. There is no eruption of visible fire from it, but a heat issues from the chinks near the top, too strong to be borne by the hand when it is held near them. We had received from Dr Heberden, among other favours, some salt which he collected on the top of the mountain, where it is found in large quantities, and which he supposed to be the true natrum or nitrum of the ancients: He gave us also some native sulphur exceedingly pure, which he had likewise found upon the surface in great plenty. On the next day, Saturday the 24th, we came into the north-east trade-wind, and on Friday the 30th saw Bona Vista, one of the Cape de Verd Islands; we ranged the east side of it, at the distance of three or four miles from the shore, till we were obliged to haul off to avoid a ledge of rocks which stretch out S. W. by W. from the body, or S.E. point of the island, to the extent of a league and a half. Bona Vista by our observation lies in latitude 16° N. and longitude 21° 51′ west. On the 1st of October, in latitude 14° 6′ N. and longitude 22° 10′ W. we found the variation by a very good azimuth to be 10° 37' W. and the next morning it appeared to be 10°. This day we found the ship five miles a-head of the log, and the next day seven. On the 3d, hoisted out the boat to discover whether there was a current, and found noon, we had an observation in 26° 13′ 51′′ latitude, and 16° 58 25 longitude. Between six in the morning and noon we had lessened our latitude 21' 5.", and increased our longitude 19 15". The ship was consequently, at the time we saw the pic, in 26° 35′ 45′′ lat. and 16° 39 10 long. and as, according to Borda and Pingre, the pic lies in 28° 17′ N. lat. and 19° 00′ W. long. of Paris, or 16° 40 of Greenwich, we must have seen it at six o'clock at the distance of 101 miles, and due north of us, in which direction it in fact bore. In very clear weather the pic may be seen 25 miles farther off from the mast-head; but this is the greatest distance which it is visible even from that height, and under the most fa vourable circumstances. The elevation of the pic has been determined by several observations. Borda's calculation, which is founded on a geometrical admeasurement, and is conceived to be the most correct, makes it 1905 toises, or 11,430 feet." The relations which some authors have given of the height of this famous pic or peak, are extravagant beyond all credibility. The reader will meet with some of them in Crutwell's Gazet teer.-E. 1 found one to the eastward, at the rate of three quarters of a mile an hour. During our course from Teneriffe to Bona Vista we saw great numbers of flying fish, which from the cabin-windows appear beautiful beyond imagination, their sides having the colour and brightness of burnished silver; when they are seen from the deck they do not appear to so much advantage, because their backs are of a dark colour. We also took a shark, which proved to be the Squalus Carcharias of Linnæus. Having lost the trade-wind on the 3d, in latitude 12° 14′, and longitude 22° 10′, the wind became somewhat variable, and we had light airs and calms by turns. On the 7th, Mr Banks went out in the boat, and took what the seamen call a Portuguese man of war; it is the Holuthuria Physalis of Linnæus, and a species of the Mollusca. It consisted of a small bladder about seven inches long, very much resembling the air-bladder of fishes, from the bottom of which descended a number of strings of a bright blue and red, some of them three or four feet in length, which upon being touched sting like a nettle, but with much more force. On the top of the bladder is a membrane which is used as a sail, and turned so as to receive the wind which way soever it blows: This membrane is marked in fine pink-coloured veins, and the animal is in every respect an object exquisitely curious and beau tiful. We also took several of the shell-fishes, or testaceous animals, which are always found floating upon the water, particularly the Helix Janthina and Violacea; they are about the size of a snail, and are supported upon the surface of the water by a small cluster of bubbles, which are filled with air, and consist of a tenacious slimy substance that will not easily part with its contents; the animal is oviparous, and these bubbles serve also as a nidus for its eggs. It is probable that it never goes down to the bottom, nor willingly approaches any shore; for the shell is exceedingly brittle, and that of few fresh-water snails is so thin: Every shell contains about a tea-spoonful of liquor, which it easily discharges upon being touched, and which is of the most beautiful red-purple that can be conceived, It dies linen cloth, and it may perhaps be worth enquiry, as as the shell is certainly found in the Mediterranean, whether it be not the Purpura of the ancients.* On the 8th, in latitude 8° 25 north, longitude 22° 4' west, we found a current setting to the southward, which the next day in latitude 7° 58′, longitude 22° 13, shifted to the N.N.W. W. at the rate of one mile and a furlong an hour. The variation here, by the mean of several azimuths, appeared to be 8.39 W. On the 10th, Mr Banks shot the black-toed gull, not yet described according to Linnæus's system; he gave it the name of Larus crepidatus: It is remarkable that the dung of this bird is of a lively red, somewhat like that of the liquor procured from the shells, only not so full; its principal food therefore is probably the Helix just mentioned. A current to the N.W. prevailed more or less till Monday the 24th, when we were in latitude 1° 7′ N. and longitude 28° 50′. On the 25th we crossed the Line with the usual ceremo nies, in longitude 29° 30', when, by the result of several very good azimuths, the variation was 2° 24. On the 28th, at noon, being in the latitude of Ferdinand Noronha, and, by the mean of several observations by Mr Green and myself, in longitude 32° 5' 16" W. which is to the westward of it by some charts, and to the eastward by others, we expected to see the island, or some of the shoals that 2 It is quite impossible to discuss this subject here. But it may be worth while to refer the learned reader for some curious information about it, to the illustrious Bochart's work entitled Hierozoicon, Part II. Book V. Ch. II. There are several sorts of sea-shells, that yield the pur. ple-dye so much esteemed among the ancients. Pliny, who has written on the subject, divides them into two classes, the buccinum and purpura, of which the latter was most in request. According to him, the best kinds were found in the vicinity of Tyre. That city was famous for the manufacture of purple. To be Tyrio conspectus in ostro, seemed, in the estimation of the Mantuan poet, essential to his due appearance in honour of Augustus, Geor. 3-17. But several other places in the Mediterranean afforded this precious article. Thus Horace speaks of Spartan purple, Nec Laconicas mihi Trabunt honestæ purpuras clientæ. The English reader will be much pleased with several interesting remarks as to the purple and other colours known to the ancients, given in President Goguet's valuable work on the origin of laws, arts. &c. &c. of which a translation by Dr Henry was published at Edinburgh 1761.-E. that are laid down in the charts between it and the main, but we saw neither one nor the other. In the evening of the 29th, we observed that luminous appearance of the sea which has been so often mentioned by navigators, and of which such various causes have been assigned; some supposing it to be occasioned by fish, which agitated the water by darting at their prey, some by the putrefaction of fish and other marine animals, some by electricity, and others referring it to a great variety of different causes. It appeared to emit flashes of light exactly resembling those of lightning, only not so considerable, but they were so frequent that sometimes eight or ten were visible almost at the same moment. We were of opinion that they proceeded from some luminous animal, and upon throwing out the casting-net our opinion was confirmed: It brought up a species of the Medusa, which when it came on board had the appearance of metal violently heated, and emitted a white light: With these animals were taken some very small crabs, of three different species, each of which gave as much light as a glow-worm, though the creature was not so large by nine-tenths: Upon examination of these animals, Mr Banks bad the satisfaction to find that they were all entirely new.3 On Wednesday the 2d of November, about noon, being in the latitude of 10° 38′ S. and longitude 32° 13′ 43′′ W. we passed the Line, in which the needle at this time would have pointed due north and south, without any variation: For in the morning, having decreased gradually in its deviation for some days, it was no more than 18′ W. and in the afternoon it was 34' east. On the 6th, being in latitude 19° 8 south, longitude 35° 50′ west, the colour of the water was observed to change, upon which we sounded, and found ground at the depth of thirty-two fathoms; the lead was cast three times within about four hours, without a foot difference in the depth or quality of the bottom, which was coral rock, fine sand, and shells; we therefore supposed that we had passed over the tail of the great shoal which is laid down in all our 3 The reader is referred to the account of Captain Krusenstern's circumnavigation, for a very satisfactory relation of an experiment on this subject, which clearly proves the truth of the opinion above stated, as to the cause of the shining appearance so often noticed at sea. It is too long for quotation in this place.-E. |