328 Lieutenant R. Strachey on the 



convey definite ideas of position in so vast and complicated 

 a mass of mountains. In spite of every care, they will con- 

 stantly be liable to misconception, as must always be the 

 case where a restricted signification is arbitrarily applied, in 

 a discussion of this sort, to expressions which of themselves 

 have an extended general meaning.* 



As a substitute for the declivities, then, the best standard 

 that occurs to me, to which to refer when alluding to the ele- 

 vation of the snow-line at any place, is the general mass of 

 perpetual snow, found on the more elevated parts of the 

 Himalaya, the belt of perpetual snow, which, as I before 

 stated, is about 35 miles in breadth, and runs along the 

 northern boundary of the chain. Instead of the height of the 

 snow-line on the northern or southern declivity, I shall there- 

 fore say, the height at the northern or southern limit of the 

 belt of perpetual snow, where the limits of the belt of perpetual 

 snow are to be understood as having exactly the same rela- 

 tion to the snowy surface in a horizontal plane that the snow- 

 line has in a vertical. 



It remains for me to define clearly what is meant by the 

 snow-line, and I cannot do better than adopt the words of M. 

 Humboldt, who says, " the lower limit of perpetual snow in 

 a given latitude is the boundary line of the snow which re- 

 sists the effect of summer ; it is the highest elevation to 

 which the snow-line recedes in the course of the whole year. 

 We must distinguish between the limit thus defined, and 

 three other phenomena; viz., the annual fluctuation of the 

 snow-line ; the phenomena of sporadic falls of snow, and the 

 existence of glaciers." — (Costnos, Trans., t. i., p. 327.) 



Having disposed of these preliminaries, which are essen- 

 tial to the proper apprehension of the subject, I sliall pro- 

 ceed to examine the data from which the elevation of the 

 snow-line is to be determined. In doing this, it will, I think, 

 be more convenient for me, both for the northern and south- 

 ern limits, to explain, first, my own views, and afterwards to 

 follow M. Humboldt's authorities, and point out the errors 

 into which they have fallen. 



* As a specimen, vide Captain Hutton's I'apers, noticed hereafter. 



