Histoire Natarelle des lies Canaries. 477 



5. La region des cumbre, ou celle 



des Retamas blancas, . 10.380. cl. N. Scotland, Drontheim. 



The first zone is considered to be too restricted, and that it should 

 have extended at least 400 feet higher. The second is not suffi- 

 ciently denned, from the variable circumstances which influence the 

 distribution of the Cerealia and cultivated plants. The third zone, 

 or that of the forests, is liable to the same objection, a want of suffi- 

 cient definition ; while the indications of the temperature, and the 

 comparison of it with the climates of Europe, do not give an exact 

 idea of the state of the atmosphere in each region, because there is 

 no proportion of time between the seasons of heat and those of cold. 

 The olive, indigenous to the Canaries, and growing at an elevation 

 of 2,109 feet, has never been naturalized in the basin of the Po, a 

 fact at variance with the stated resemblance of this zone to the cli- 

 mate of Lyons and Lombardy. Neither can the clime of the fourth 

 region be compared with that of Germany or Scotland. In those 

 countries Pimis Canariensis can never be kept alive out of the green- 

 house. 



In fixing their own divisions of the vegetation of TenerifFe, MM. 

 Webb and Berthelot have taken almost every local circumstance 

 into consideration. From numerous observations on the tempera- 

 ture, made at different heights, and kept simultaneously in various 

 stations, the following results have appeared. To the height of 

 1,500 the temperature continues very equal, varying only from one 

 to two degrees, according to the direction of the openings of the 

 valleys, or as it may be influenced by the exposure, nature of the 

 soil, or proximity to wooded hills. According to the same local 

 circumstances, its variation above a height of 1,500 to about 4,000 

 is from two to eight degrees ; but in this region clouds and vapours 

 almost constantly rest on the hills and slopes, and afford a supply 

 of moisture most favourable for vegetation, and the plants are thus 

 found here, growing luxuriantly, and distributed in large masses. 

 From 4,000 to the summit of the peak there is not the same mois- 

 ture furnished by vapour, while the temperature diminishes pro- 

 portionally to the ascent, and taking a line along the slope of 8,000, 

 a difference is perceived of from nine to seventeen or eighteen de- 

 grees below the temperature of the coast. Upon these deductions, 

 and allowing for variation from locality and the state of the atmo- 

 sphere, our authors have divided TenerifFe into three great climates, 

 and have given three tables, which, while they completely explain 

 their views, are otherwise so extremely interesting, that we are in- 

 duced to copy them. 



