July, 1849. TALLUM, CLIMATE, Ac, OF. 69 



change in the climate, which characterises all these rear- 

 ward lofty valleys, where very little rain falls, and that 

 chiefly drizzle ; but this is so constant that the weather 

 feels chilly, raw, and comfortless, and I never returned dry 

 from botanising. The early mornings were bright with 

 views northwards of blue sky and Kinchinjhow, while to the 

 south the lofty peak of Tukcham, though much nearer, was 

 seldom seen, and black cumuli and nimbi rolled up the steep 

 valley of the Lachen to be dissipated in mist over Tallinn. 

 The sun's rays were, however, powerful at intervals during 

 the forenoon, whence the mean maximum temperature of 

 July occurred at about 10 a.m. The temperature of the 

 river was always high, varying with the heat of the day from 

 47° to 52°; the mean being 50°. 



These streams do not partake of the diurnal rise and fall, 

 so characteristic of the Swiss rivers and those of the western 

 Himalaya, where a powerful sun melts the glaciers by 

 day, and their head-streams are frozen by night. Here 

 the clouds alike prevent solar and nocturnal radiation, the 

 temperature is more uniform, and the corroding power of 

 the damp southerly wind that blows strongly throughout 

 the day is the great melting agent. One morning I saw a 

 vivid and very beautiful halo 20° degrees distant from the 

 sun's disc ; it was no doubt caused by snow in the higher 

 regions of the atmosphere, as a sharp shower of rain fell 

 immediately afterwards : these are rare phenomena in 

 mountainous countries. 



The Singtam Soubah visited me daily, and we enjoyed 

 long friendly conversations : he still insisted that the Yang- 

 choo (the name he gave to the Lachen at this place) was 

 the boundary, and that I must not go any further. His 

 first question was always " How long do you intend to 

 remain here ? have you not got all the plants and stones 



