TENERIFFE. 



mile. The number of acres is 985,600, wliicli, upon an aver- 

 age, allots about 10 acres to every individual in it ; the num- 

 ber of inhabitants being calculated to be nearly 100,000. Of 

 thefe there is annually a conliderable migration to the Spanilh 

 colonics in South America. The poor of TcncrifTe arc ealily 

 perfuaded to migrate, as the proprietors of the land do not 

 give them futficient employment throughout the year ; and 

 they have not the refource of manufaftures, except a trifling 

 one in filk, chiefly ftockings. The price of labour is under 

 a fliilling a day ; and, befide corn and roots, the principal 

 food of the common people is confined to cod-fidi, caui^ht 

 on the neighbouring coaft of Africa, or imported from 

 North America. This ifland was formerly called Nivaria, 

 which appellation it derived from the circle of fnow that 

 furrounded the peak, of Tenda, now called the peak of Tene- 

 riife ; which name was given to it, as it is faid, by the in- 

 habitants of Palma ifland, in whole language tener fignifies 

 fiiow, and eff'e a mountain. The figure of this ifland is tri- 

 angular, as it extends into three capes, the neareft: being 

 about 80 leagues or more from the coaft of Africa. The 

 hiftorical celebrity of this ifland has been very much owing 

 to its Peak, elevated to a conliderable height from a bafe 

 lying a little to the S.W. of its centre. Of its height we 

 have various ft:atements by different writers, who have af- 

 cended to its fummit. Dr. Heberden, whofe obfervations 

 in afcending it are publiflied in the Phfl. Tranf. vol. xlvii. 

 makes its height above the level of the fea to be 2566 fa- 

 thoms, or 15,396 EnglilTi feet ; and he fays that this mea- 

 fure was confirmed by two fubfequent obfervations by him- 

 felf, and another made by Mr. Crofle, the conful. Never- 

 thelefs, chevalier de Borda, who meafured the height of this 

 mountain in Augufl; 1776, makes it to be only 193 1 French 

 toifes, or 12,340 Englifli feet. Mr. Johnftone, a merchant 

 of Madeira, being on board fliip in the offing of Orotava, 

 took the angles made by a line from the horizon to the 

 fummit of the Peak, at tvi'O different fpots, and meafuring 

 the diftance between them by the log, determined the per- 

 pendicular height of the Peak to be 2023 Englilh fathoms, 

 being nearly the fame as Chev. de Borda had calculated 

 from a bafe meafured upon land. From the comparative 

 obfervations of Monf. de Borda's barometers, upon the 

 Peak, and by the fea-iide, the mountain's heigiit came within 

 two fathoms of the geometrical meafurement. The Hon. 

 Grey Bennet, who made a journey to the top of the Peak 

 in 1 8 10, ftatcs its height to be about 12,500 feet. M. de 

 Lemanon and Monges, on the 26th of Auguft 1785, afcended 

 the Peak, and fl;ating its elevation above the level of the fea 

 to be near 1900 toifes, made lome chemical experiments, in 

 order to compare the phenomena at that height witli thofe 

 which occur in our laboratories. They oblerve, that the 

 crater of the Peak is a perfeft folfatara or laboratory of 

 fulphur ; its diameter being about 50 toifes by 40, rifing 

 with a ftcep and rapid afcent from W. to E. On the edges 

 of the crater, and particularly towards the loweft part, are 

 feveral apertures or vents, exhahng watery and fulphuric acid 

 vapours, the heat of which raifed the thermometer from 9° 

 to 34°. The interior of the crater is covered with yellow, 

 red, and white clay, and fragments of lava pai-tly decom- 

 pofed. xUnder thefe were fovmd beautiful cryftals of ful- 

 phur, forming rhomboidal oftohedra, fome of which were 

 an inch thick. The fl^eam exhaled from the apertures was 

 pure water, not at all acid. The evapoa'atiou of liquids, 

 and the cold thus produced, were very confiderable. The 

 aftion of the acids on metals, earths, and alkalies was flow, 

 and the bubbles that efcaped during ihe eff^ervefcence were 

 much larger than ufual. The production of vitriols aff^urded 

 a fingular phenomenon. That of iron inftantly- aflumed a 



fine violet colour, and that of copper precipitated with * 

 very vivid hue. The fmell and ilrc ngtii of liquors appeared 

 not to have loll any thing at this elev.ition, and the volatile 

 alkali, ether, and alcohol, retained the fame ftrength. Seve- 

 ral experiments were made with a view of afcertaining the 

 nature of the vapours exhaled from the crater, and whether 

 they contained inflammable air, fixed air, or marine acid. 

 From tiiefe he concluded that no fixed air exhaled from the 

 crater, and alfo that the atmofpheric air refting upon it con- 

 tains very little, and that the inflammable vapours and ful- 

 phuric acid gas alone are confiderable, and indeed perceivable. 

 The atmofpheric eledricity was confiderable and pofitive. 

 Many new varieties of volcanic fchorls were difcovered. 

 See La Peroufe's Voyage, vol. li. p. 226, &c. 



Dr. Heberden gave fir Jofeph Banks fome fait which he 

 coUedted on the top of the mountain, where it is found in 

 large quantities, and which he fuppofed to be the true na- 

 trum, or nilrum, of the ancients. Although the vortex ap- 

 pears fliarp, and of the exadl refemblance of a cone, yet it \* 

 flat for the extent of an acre of ground, in the centre of 

 which is a dreadful volcano, whicii frequently breaks out 

 into flames, fo violent as to fhake tlie whole ifland with an 

 incredible force. Smoke conftantly iffues from the moun- 

 tain, near its fummit, but no eruption has occurred fince the 

 year 1704, when the port of Garrachica was deilroyed, and 

 the harbour filled by the lava. The ifland of Teneriffc is 

 divided in the middle by a ridge of mountains, which have 

 been compared to the roof of a church, the Peak forming 

 the fpire or fteeple in the centre. An autlior well acquainted 

 with the ifland fays, that if you divide it into twelve parts, 

 ten of thefe confill of rocks, woody and inaccefTiblc moun- 

 tains and vineyards ; and yet, from the fmall remainder of 

 arable ground, he has feen 250,000 hanackes of wheat, be- 

 fides immenfe quantities of rye and barley, produced. The 

 greatefl part of the ifland is volcanic, and all its rocks are 

 lava. Mr. Bennet (Tranf. of the Geological Society, vol.ii.) 

 conceives, that formerly a very large crater, i 2 miles in dia- 

 meter, exifled, the fides of which, under the name of Las 

 Foldas, may be flill traced a great way. The crater at the 

 top of the Peak is but fmall, and fomewhat in activity. The 

 lavas vary in their appearance : fome are compofed ot horn- 

 blende and felfpar, without any foreign body ; thefe are 

 porphyritic : fome are compofed of green-ftone, and contain 

 olivin, augite, and zeolites : fome are bafaltic ; thefe de- 

 compofe the fooneft, and conftitute the moll fertile foil ; 

 there are alfo pumice in abundance, tufa afhes, and a lava re- 

 fembling obfidian. Every circumilance, it is faid, argued 

 in favour of a volcanic formation, except the form ot the 

 mountains, whofe irregular ridges, declivities, and afceuts, 

 appeared very different from thofe exhibited by volcanic 

 mountains. In the plain beyond Laguna, on the Orotava 

 fide, the foil was not in the leaft volcanic, but compofed of 

 fine mould, or virgin earth ; a mixture of clay, vegetable 

 earth, and fand. Hollows, 30 feet deep, left dry by rivu- 

 lets, exhibit no volcanic appearance. Immediately under 

 the fuperficial foil was a layer of deep loam, next, one of 

 tougli clay, and all below was an irregular mixture of clay 

 and fand. Elfewherc the hills confifled of indurated clay, 

 and clay and iron, without any marks of the action ot fire. 

 In the whole ifland, there is no pure flint or fand-ftone. Its 

 mountains are of two forts ; one, evidently volcanic ; the 

 other, primary and compofed of indurated clay, or of clay 

 a.id calx of iron. In the low plains are layers of loofe and 

 foft argillaceous earth. (See Dr. Gillan's remarks in the 

 I ft vol. of the Embafl"y to China, p. 1 18 — 120.) Although 

 the people live on fcanty and coarfe fare, they are not much 

 fubjed to difeafe, and inftances of longevity, even to 100 



ycar«, 



