172 SNOW-LINE. 



could never make ice (operating, however, on a small scale) 

 when the temperature exceeded 41° F. on the level of the pits ; 

 but on such occasions the temperature is much higher at some 

 distance from the ground, and a series of bottles filled with 

 water, suspended from a mast of about seventy feet high, 

 exhibited an increase of 1° for every ten feet of elevation. 

 Mr. Scott adds, that therefore Sir H. Davy is right in sajing 

 ice may be made when the thermometer is above 50°, if he 

 allude to the upper regions of the air, or hills of moderate 

 height ; but, as has been already said, it cannot be made 

 when the thermometer, suspended at three feet from the 

 ground on the plain, stands at about 41°. Mr. Scott's ex- 

 periments extend to the height of 3400 feet, at which eleva- 

 tion, on a detached mountain, the temperature of the air at 

 sunrise is several degrees higher than in the plain of Bengal. 



6. Snoio-Une. — ^Although, as already remarked, the ther- 

 mometer sometimes stands as low as 28° F. in Malwah, yet, 

 as far as we know, snow has not been obsen'ed in India to 

 the south of the grand Himmaleh mountain-barrier. On 

 several ranges of this vast alpine land snow lies all the year. 

 The lower "boundary of this snowy covering is named the 

 snow-line, which varies in height according to the season 

 of the year, being highest during sununer and lowest during 

 winter. Of late years the height of this line in different 

 parts of the world has engaged the particular attention of 

 meteorologists, and the investigation has led to interestmg 

 results. The subject has been pursued with energy among 

 the Himmalehs by several active British officers, — of whom 

 Webb, Gerrard, and Herbert are the most distinguished. 

 In November, 1817, Captain Webb published a memoir on 

 the heights of the Himmalehs, in which, by tracing the 

 Gauri river upwards, he found that it burst from the snow 

 at the elevation of 11, .543 feet, — a striking coincidence be- 

 tween actual obserA'ation and the calculated formula of au- 

 thors, which assigns 11,400 feet. Mr. Golebrooke, in a 

 paper published in Brande's Journal from the observations 

 of Captain Webb, for the first time remarked that the inferior 

 limit of perpetual snow does not everywhere descend so low 

 as theory would lead us to conclude. 



According to theory, the height of the snow-line between 

 latitudes 27° and 35°, about the range of latitude of the 

 Himmalehs, is as follows : — 



