Reviews, and Notices respecting New Books. 1 35 



Berberis Asiatica, aristata and Wallichiana ; PotentiUa atrosan- 

 guinea and Nepalensis j Salvia nubicola, and many others." (p. 42.) 



When we search into the present distribution of animal and vege- 

 table life over the face of the globe, there are few subjects of greater 

 interest than the correspondence or difference, as the case may be, 

 between the animal or vegetable forms which are found under 

 nearly equal climates, particularly as regards temperature, whether 

 such equal temperatures be obtained by variations in altitude above 

 the level of the sea in different latitudes, or by the equal approxi- 

 mations of localities to the equator or to the poles, as may happen. 

 The Himalayan mountains rising to a great height in a warm lati- 

 tude, and bounding the lower lands of India on the northward, ne- 

 cessarily afford excellent opportunities for studying the effects of 

 diminishing temperature on animal and vegetable life as the tra- 

 veller proceeds from the heated plains at the southern base of these 

 mountains, and rises to the line of perpetual snow of the highest 

 range. These opportunities were not likely to be overlooked or 

 lost by a person of Mr. Royle's acquirements, and accordingly 

 those parts of his work which are published, contain some very 

 remarkable facts connected with this subject, and it is understood 

 that the parts which are to follow will afford us important additions 

 to them. 



Mr. Royle divides the slopes of the Himalayan mountains into 

 three belts, the first may be considered to reach " to between four 

 and five thousand feet of elevation, as several tropical perennials 

 extend to the latter, and snow does not usually fall below the 

 former. The second belt may be conceived to embrace the space 

 between five and nine thousand feet of elevation, as the winter's 

 snow is always melted from such elevations before the accession of 

 the rainy season, and the upper is nearly the limit to which the 

 herbaceous plants of tropical genera extend. The third belt may 

 be taken from this elevation up to the highest limits from which snow 

 melts away on the southern face of the Himalayan mountains." 

 (p. 16.) Among the difficulties noticed by the author which attend 

 this division of the slopes of these mountains into belts of vegeta- 

 tion, he adduces that " produced by the great difference in the ve- 

 getation of the northern and southern faces of the very same range 

 or mountain, so that frequently a straight line running along the 

 summit of the ridge may be seen dividing the luxuriant arboreous 

 and shrubby vegetation of the northern face from the brown, bar- 

 ren, and grassy covering of the southern slope." (p. 16.) 



Mr. lloyle offers the following explanation of the remarkable 

 fact, that the limit of the line of snow rises higher on the northern 

 than on the southern flank of the Himalayas. 



" From the details which have been given, it seems abundantly 

 clear that the elevation of the Indian snowy range is sufficient to 

 prevent the passage across of the clo.udy masses which deluge the 

 plains of Northern India with rain, both in the cold and in the 

 warm season. The atmosphere, therefore, on the northern face of 

 the Himalayas preserves unimpaired the dryness, which is the 

 characteristic of the rarefied air of lofty situations: hence the little 



