130 CLIMATE AND VEGETATION OF 



collection of a nuiltitude of observations of my own. The 

 means of the month are taken by meaning the daily maxima and 

 minima, which I tliink gives too liigh a result. Those for ter- 

 restrial and nocturnal radiation are accurate as far as they go, 

 that is to say. tiiey are absolute temperatures taken by myself, 

 whicii may, I believe, be recorded in any year, but nuuh liigiier 

 are no doubt often to be obtained. The dew-points and satura- 

 tions are generally calculated from the mean of two day ob- 

 servations (10 A.M. and 4 p.m.) of the wet bulb tiiermometer, 

 toiJfether with the minimum, or are taken from observations of 

 Daniell's hygrometer. The dew-point and temperature are as- 

 sumed to coincide onlj^ at the hour of minimum temperature ; 

 but as the}^ do coincide for, on the average, 10 hours of every 

 24. tins method obviously gives too low a dew-point. On the 

 other hand, the wet bulb observations, or hysrometer, were never 

 taken at the hours of greatest dryness : and as I find the mean of 

 the temperatures of 10 a.m., 4 p.m., and the minimum to coin- 

 cide within a few tenths with the mean temperature of the whole 

 year, I assume that the mean of the wet bulb observations of 

 the same hours will give a sutHciently accurate approach to that 

 of the 24 hours. The climate of Darjiling station has been in 

 some degree altered by extensive clearances of forest, which 

 render it more variable, more exposed to night frosts and strong 

 sun, and to drought, the drying up of small streams being one 

 direct consequence. My own observations were taken at Mr. 

 Hodgson's house, elevated 7450 feet, the position of which I have 

 indicated at p. 2 of this volume (in a note), where the dift'erences 

 of climate due to local causes are sufficiently indicated to show 

 that in no two spots could similar meteorological results be ob- 

 tained. At my station, for instance, tlie uniformity of tempera- 

 ture and humidity is infinitely more remarkable than at Dr. 

 Chapman's, possibly from my guarding more effectually against 

 radiation, and from the greater forest about Mr. Hodgson's house. 

 I have not, however, ventured to interfere with the temperature 

 columns on this account. Such as they are, I believe they afford 

 amply sufficient data for the horticulturist who is anxious to exert 

 his skill and ingenuity in the cultivation of Himalayan plants in 

 general, and especially of Sikkim ones, though they will little 

 avail him except he be previously master of the climate of 

 England, for which purpose I would most strongly urge the 

 study of Mr. Daniell's essay before alluded to, and the many 

 papers in this .Journal and elsewhere of Mr. Thompson, of the 

 Horticultural Society's Gardens, which contain a vast amount of 

 valuable matter, carefully collected and extremely well arranged. 



