422 The Turaee and Outer Mountains of Kumaoon. [May, 



don ; but the fact that few of the trees indigenous at that altitude can 

 stand an English winter, points to a signal difference of conditions in the 

 distribution of Himalayan heat and moisture. Dr. Royle well observes, 

 after the astronomers, that, in advancing north from the equator, the 

 sun passes over 12° in the first month, 8° in the second, and only 3^° 

 in the third ; and that hence, from his longer presence there, and the 

 greatly increased length of the day, the heat is more intense at the 

 tropic than at the equator : at the latter, the sun is more or less verti- 

 cal for about six days only ; at the latter for nearly two months. The 

 distance of the Himalaya from the northern Tropic is not great ; and 

 where we have a southern exposure, is more than compensated ; there 

 indeed, the sun's rays strike vertically with intolerable power, augment- 

 ing in the ratio of our ascent, so that one is absolutely scorched while 

 walking on a glacier. What a contrast also between the generally serene 

 brilliant sky, and extremely \ dry atmosphere of the Himalaya during 

 eight or nine months of the year, and the cloudy canopy which so 

 generally rests over the British Islands ! The sun's arrival at the Tro- 

 pic of Cancer is marked here by that of the rainy season, when the 

 previously dry atmosphere is suddenly, and for three months, saturated 

 with moisture, with a sun potent enough to knock down an ox, when 

 he does show himself, which is not seldom. During this period, one 

 is alternately baked and chilled half a dozen times during the twenty- 

 four hours, and that not in the low confined vallies, but on perfectly 

 open ridges such as Almorah, where it is, consequently, a matter of some 

 difficulty to adjust one's clothing to the frequent fluctuations of tempe- 

 rature, the annual change of dress which Mr. Fortune describes amongst 

 the Chinese being here diurnal. The result at Almorah, Kussowlee, 

 &c, appears to be as much, though not so dangerous sickness as in the 



instrument (actinometer) at the same time :" again : " estimating the loss of radiant heat 

 by a vertical passage through the atmosphere at only 25 per cent. ; at an angle of eleva- 

 tion of 25°, the force of the solar rays would be reduced to a half, and at 5° to one twen- 

 tieth part," from the varying thickness and transparency of the atmosphere. Hence the 

 necessity for shelter except in the morning and afternoon. 



" The increased intensity of the sun's rays at great elevations supplies the probable rea- 

 son (suggested to me by Lt. R. Strachey) of a phenomenon noted on a former occasion, 

 \iz. that the seeds of the same species of plant ripen much earlier on the lofty passes of 

 the Himalaya than at their base. 



