412 CLIMATE OF SIKKIM. Appendix F. 



temperature at the time is 51°, and the absolute amount of 

 cold therefore immaterial.. The mean minimum of London is 38°, 

 and, when lowered 5*5° by radiation, the consequent cold is very- 

 considerable. Mr. Daniell, in his admirable essay on the climate 

 of London, mentions 17° as the maximum effect of nocturnal 

 radiation ever observed by him. I have registered 16° in April 

 at Dorjiling ; nearly as much at 6,000 feet in February ; twice 

 13°, and once 14° 2 in September at 15,500 feet ; and 10° in 

 October at 16,800 feet ; nearly 13° in January at 7,000 feet ; 

 14° 5 in February at that elevation, and, on several occasions, 

 14° 7 at 10,000 feet in November. 



The annual rain-fell at Dorjiling averages. 120 inches (or 10 feet), 

 but varies from 100 to 130 in different years ; this is fully three 

 times the amount of the average English fall*, and yet not one-fourth 

 of what is experienced on the Khasia hills in Eastern Bengal, where 

 fifty feet of rain falls. The greater proportion descends between June 

 and September, as much as thirty inches sometimes falling in one 

 month. Erom November to February inclusive, the months are 

 comparatively dry ; March and October are characterised by violent 

 storms at the equinoxes, with thunder, destructive lightning, and 

 hail. 



The rain-gauge takes no account of the enormous deposition from 

 mists and fogs : these keep the atmosphere in a state of moisture, 

 the amount of which I have estimated at 0'88 as the saturation-point 

 at Dorjiling, 0*83 being that of London. In July, the dampest 

 month, the saturation-point is - 97 ; and in December, owing to the 

 dryness of the air on the neighbouring plains of India, whence 

 dry blasts pass over Sikkim, the mean saturation-point of the month 

 sometimes falls as low as 0*69. 



The dew-point is on the average of the year 49° 3, or 3° below the 

 mean temperature of the air. In the dampest month (July) the 

 mean dew-point is only eight-tenths of a degree below the tempera- 

 ture, whilst in December it sinks 10° below it. In London the 



* The general ideas on the subject of the English rain-fall are so very vague, 

 that I may be pardoned for reminding my readers that in 1852, the year of extra- 

 ordinary rain, the amounts varied from 2 8 5 inches in Essex, to 50 inches at 

 Cirencester, and 67*5 (average of five years) at Plympton St. Mary's, and 102'5 at 

 Holme, on the Dart. 



