[Footnote 67: The reader need scarcely be apprized of the necessity of verifying on modifying the account of some of the particulars now given respecting Madeira, by an appeal to more recent authorities. A hint to this effect is sufficient, without further occupying his attention on the subject.--E.]
The tides at this place flow at the fall and change of the moon, north and south; the spring-tides rise seven feet perpendicular, and the neap-tides four. By Dr Heberden's observation, the variation of the compass here is now 15° 30' west, and decreasing; but I have some doubt whether he is not mistaken with respect to its decrease: We found that the north point of the dipping needle belonging to the Royal Society dipped 77° 18'.
The refreshments to be had here, are water, wine, fruit of several sorts, onions in plenty; and some sweetmeats; fresh-meat and poultry are not to be had without leave from the governor, and the payment of a very high price. We took in 270 lib. of fresh, beer, and a live bullock, charged at 613 lib. 3,032 gallons of water, and ten tons of wine; and in the night, between Sunday the 18th and Monday the 19th of September, we set sail in prosecution of our voyage.
When Funchiale bore north, 13 east, at the distance of 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. 1/2 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 to latitude 80° 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. 1/2 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.[68] Its appearance at sunset was very striking; 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.
[Footnote 68: 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 account 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 Tenerifle, 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 decline. Every one of the mountains which surround the pic, 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 Tenerifie) 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 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' 53", 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 dear 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 favourable 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 Gazeteer.--E.]
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 32° 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 one to the eastward, at the rate of three quarters of a mile an hour.