INTRODUCTION. 9 



* 



chain of the Himalaya is also wanting in the imposing pheno- 

 mena of volcanoes, which in the Andes and in the Indian 

 Archipelago often reveal to the inhabitants, under the most 

 terrific forms, the existence of the forces pervading the interior 

 of our planet. 



Moreover, on the southern declivity of the Himalaya, where 

 the ascending current deposits the exhalations rising from a 

 vigorous Indian vegetation, the region of perpetual snow 

 begins at an elevation of 11,000 or 12,000 feet above the 

 level of the sea,* thus setting a limit to the development of 



p. 510, Cas.), twenty-five oaks, four birches, two chesnuts, seven maples, 

 twelve willows, fourteen roses, three species of strawberry, seven species 

 of Alpine roses (rhododendra), one of which attains a height of 20 feet, 

 and many other northern genera. Large white apes, having black faces, 

 inhabit the wild chesnut-tree of Kashmir, which grows to a height of 

 100 feet, in lat. 33 (see Carl Von Hugel's Kaschmir, 1840, 2nd pt., 

 249.) Among the coniferse, we find the Pinus deodwara, or deodara (in 

 Sanscrit, dcwa-daru the timber of the gods), which is nearly allied to 

 Pinus cedrus. Near the limit of perpetual snow, flourish the large and 

 showy flowers of the Gentiana venusta, G. Moorcroftiana, Swertia pur- 

 purescens, S. speciosa, Parnassia armata, P. nubicola, Poeonia Emodi, 

 Tulipa stellata ; and, besides varieties of European genera peculiar to these 

 Indian mountains, true European species, as Leontodon taraxacum, Pru- 

 nella vulgaris, Galium aparine, and Thlaspi arvense. The heath men- 

 tioned by Saunders, in Turner's Travels, and which had been confounded 

 with Calluna vulgaris, is an Andromeda, a fact of the greatest importance 

 in the geography of Asiatic plants. If I have made use, in this work, of 

 the unphilosophical expressions of European genera, European species, 

 groiving wild in Asia, &c., it has been in consequence of the old botanical 

 language, which instead of the idea of a large dissemination, or rather of 

 the co-existence of organic productions, has dogmatically substituted the 

 false hypothesis of a migration, which from predilection for Europe, is 

 further assumed to have been from west to east. 



* On the southern declivity of the Himalaya, the limit of perpetual snow 

 is 12,978 feet above the level of the sea; on the northern declivity, or 

 rather on the peaks which rise above the Thibet, or Tartarian plateau, 

 this limit is at 16,625 feet from 30^ to 32 of latitude, whilst at the 

 equator, in the Andes of Quito, it is 15,790 feet. Such is the result I 

 have deduced from the combination of numerous data furnished by 

 Webb, Gerard, Herbert, and Moorcroft. (See my two memoirs on the 

 mountains of India, in 1816 and 1820, in the Ann. de Chimie et de Phy- 

 sique, t. iii. p, 303, t. xiv. pp. 6, 22, 50.) The greater elevation to which 

 the limit of perpetual snow recedes on the Tartarian declivity is owing to 

 the radiation of heat from the neighbouring elevated plains, to the purity 

 of the atmosphere, and to the infrequent formation of snow in an air 

 which is both very cold and very dry. (Humboldt, Asie Centrale, t. iii. 



