1837.] On the Climate of Darjiling. 309 



boiling point of water, as compared with the barometric indications. 

 As his thermometer for tbe latter object was only divided to 2°, 

 we have since despatched a new one of greater sensibility, whence we 

 hope soon to obtain valuable data for the correction of the usual 

 tables for the measurement of heights by the thermometer. The dew 

 points noted are curious, sometimes higher than the wet bulb or 

 evapoi ation point. Can this arise from an error in the Daniell's hygro- 

 meter ? We have always found a little iced water added drop by 

 drop to a little common water in a highly polished gilded silver cup, 

 the most trust-worthy mode of taking the dew point. It can be de- 

 pended on to the tenth of a degree. 



Upon the strength of our observations in the December Journal we 

 may, with confidence, calculate the altitude of Titalya, and Darjiling 

 from the three months' observations of October, December, and Janu- 

 ary*. Thus applying the constant correction of — .004 to Dr. 



Chapman's Bar. A, we have 



Altitude 



Corrected heights of the Barometer at 8§ a. M. Calcutta. Titalya. deduced. 



mean temperature of air 76°, 29.894 29.626 ft. 255.7 



At 4* p. m , ditto, 81.5 , 29.815 29514 293.5 



Average altitude of Titalya, ft._ 275.0 



For Darjiling the data are more numerous : 



Altitude. 

 Calcutta. Darjiling. calculated. 



Barom. Temp. Barom. Temp. feet. 



Dec. 1836, obs. 9 a. m. 30.098 68.0 23.367 44.6 6925.1 



Ditto, 5 p.m. 29.989 75. 23.298 47.6 6973.1 



Jan. 1837, obs. 9 a. m. 3D. 073 68. 23.322 42.1 6942.2 



Ditto, 5 p.m. 29.970 75. 23.247 43.4 6989.9 



Mean altitude by 120 obs. of the Barometer, ft. 6957.5 



The altitude of Darjiling hill by two observations of Capt. Herbert, 

 published with his report in the Gleanings of Science, is 7218 feet, or 

 250 feet higher than Dr. Chapman's house. The altitude deducible 

 from the thermometric indication of boiling water is only 6648.5 : 

 but little confidence is to be placed in the latter without a very 

 accurate instrument. It is to be remarked also, that the barometric 

 measure will shew a much closer agreement when not corrected bv 

 the multiplier for the assumed mean temperature of the stratum of 

 air between the two stations, Unconnected they stand thus: 6595.8, 

 6578.4, 6624.6, and 6619.2; the maximum discrepancy from the 

 mean 6604.5 being only 26 feet. A numerous series of barometrical 

 results from similar tables will enable us to form a more correct appre- 

 ciation of the influence of variations of temperature on the formula. 

 N. B. The barometric heights above stated have been all reduced to,3"2°. 



* We have since received the registers for February and March, which we in- 

 sert, deferring observations till the series is completed. 

 2 s 



