Appendix E. SITES OF VILLAGES. LOCAL WINDS. 393 



stream, the Teesta, and run at more or less of an angle to the latter. 

 The spurs from the east flank of one ridge cross, at their ends, those 

 from the west flank of another ; and thus transverse valleys are 

 formed, presenting many modifications of climate with regard to 

 exposure, temperature, and humidity. 



The roads from the plains of India to the watershed in Tibet 

 always cross these lateral spurs. The main ridge is too winding and 

 rugged, and too lofty for habitation throughout the greater part of 

 its length, while the river-channel is always very winding, unhealthy 

 for the greater part of the year below 4000 feet, and often narrow, 

 gorge-like, and rocky. The villages are always placed above the 

 unhealthy regions, on the lateral spurs, which the traveller repeatedly 

 crosses throughout every day's inarch ; for these spurs give off 

 lesser ones, and these again others of a third degree, whence the 

 country is cut up into as many spurs, ridges, and ranges, as there 

 are rills, streams, and rivers amongst the mountains. 



Though the direction of the main atmospheric current is to the 

 north, it is in reality seldom felt to be so, except the observer be on 

 the very exposed mountain tops, or watch the motions of the upper 

 strata of atmosphere. Lower currents of air rush up both the main 

 and lateral valleys, throughout the day ; and from the sinuosities in 

 the beds of the rivers, and the generally transverse directions of their 

 feeders, the current often becomes an east or west one. In the 

 branch valleys draining to the north the wind still ascends ; it is, in 

 short, an ascending warm, moist current, whatever course be pursued 

 by the valleys it follows. 



The sides of each valley are hence equally supplied with moisture, 

 though local circumstances render the soil on one or the other flank 

 more or less humid and favourable to a luxuriant vegetation : such 

 differences are a drier soil on the north side, with a too free exposure 

 to the sun at low elevations, where its rays, however transient, rapidly 

 dry the ground, and where the rains, though very heavy, are of shorter 

 duration, and where, owing to the capacity of the heated air for re- 

 taining moisture, day fogs are comparatively rare. In the northern 

 parts of Sikkim, again, some of the lateral valleys are so placed that 

 the moist wind strikes the side facing the south, and keeps it very 

 humid, whilst the returning cold current from the neighbouring 



