BY THE BOILING POINT OF WATER. 



239 



o-reat range of elevation, he states, that having deduced the heights by my for- 

 mula, he finds that it " is certainly not applicable to the Sikkim Himalaya," but 

 that Captain Boileau's Tables, founded on M. Recnault's, give, at all ordinary 

 elevations, a " very close approach to accuracy, on the mean of many observa- 

 tions." We find, however, from the results which Dr Hooker has himself given 

 at page 458, the average difference of the barometric and thermometric results is 

 far from showing a close agreement, and seems to throw a doubt on the suffi- 

 ciency of the observations for testing one formula rather than another. 



The average error (without respect to sign) of each observation is about 140 

 feet, or 0°26 of a degree, whilst it occasionally rises to half a degree, or even a 

 whole degree ; and this by the formula preferred by Dr Hooker. The average 

 deviation of my observations from the formula is only o, 08. 



Desiring to arrive at the exact truth, and to test the alleged inapplicability 

 of a linear formula to the Indian observations, I wrote to Dr Hooker, requesting 

 him to send me as large a selection as possible of direct comparisons between the 

 barometer and the boiling point at different heights. With this request he most 

 kindly complied, sending me (with much trouble to himself) a long series of com- 

 parisons, which he had drawn from his original note-books. From the extent 

 and range of these, I consider them well worthy of preservation, and accordingly 

 transcribe them in the following Table. 



Sikkim, Himalaya, Boiling Points. 







Boiling Point. 



Barom. 



Station. 



S.* L* 



Corrected. 



Great Rungeet River, 



210-8 



29-211 



Bhomsong, . 



210-2 



28-559 



Gt. Rungeet Guard-house, 



208-4 207-8 



27-972 



Do., 



208-4 207-7 



27-781 



Choongtam, . 



202-5 202-6 



24-697 



Dengha, 



200-6 



23-726 



Mr Muller's (Dorjiling), 



199-0 



23-372 



Do., . 



199-6 199-5 



23-358 



Dr Campbell's (Dorjiling), 



200-1 200-1 



23-369 



Mr Hodgson's (Dorjiling), 



199-5 199-3 



23-030 



Sinchul, 



197-0 



21-892 



Lachoong Village, 



196-4 



21-928 



Do., . 



196-4 



21-751 



Lamteng, 



196-3 



21<654 



Zemu Samdong, 



195-9 196-1 



21-605 



Do., . 



196-3 196-2 



21-596 



Do., . 



196-3 196-1 



21-633 



Mainom, 



193-4 



20-480 



Junction of Zemu & Thlonok, 



192-6-j- 192-6 



20-212 



Tallum Samdong, 



191-4 191-6 



19-758 



Do., . 



192-1 192-2 



19-881 



Yeumtong, . 



191-1 191-2 



19-490 



Do. 



191-8 



19-505 



* S means small and L large Thermometer. 





t 193-6 in my " Journals," by error apparently ; for I find IS 



2-6 in my Note- 1 



book and Calculatio 



i-book.— J. D. H. 





VOL. XXI. PART II. 



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