410 COURSE AND LEVELS 



the great snowy Peak Purkyul was determined. The two observed angles 

 were, on the ridge 61° 27', at Shipki 95° 1', concluded angle 23° 32'. From 

 these observations the distance of Purkyul appears to be (from Shipki) 

 28,270 feet which with its bearing 353° ] I'gives a difference of latitude of 

 4" 37' 7 and of longitude 47 '". The difference of elevation deduced from the 

 observed angle of altitude (23° 9'43') is 12,036 feet. The latitude of Purkyul 

 is then 31° 53' 17" 7. 



Again from the Hangarang Pass the bearing of this Peak was found to 

 be 62° 48' correcting for the declination of the needle. The difference of 

 latitude being 343" 2, the difference of longitude is found to be 13' 04" 

 giving the longitude of Purkyul 78° 43' 54", and that of Shipki 78° 44' 41". In 

 the same way the difference of elevation was found from the observed an- 

 gle of altitude (5° 56') to be 8021 feet giving for the absolute elevation of 

 this peak above the sea 22,731 feet, and for that of Shipki 10,095 feet. 



0. We may now compare the above result of longitude with that given 

 by the Chronometer. The rate from Kotgerh to Dudu 27 days, is seen to 

 be 7° 24""losing. At Shipki during four days halt it was 8° 52*; the mean 

 of these is 7° 9' nearly. Adopting this as the most probable rate from D6- 

 du to Shipki we have 9' 55" 3 as the error on mean time under the 1st 

 Meridian of the Survey (77° 28" 30") 15th October. The difference be- 

 tween this resultand the actual error at Shipki (1508"1) is 5' 12", 8=1° 18' 

 32" giving the longitude of Shipki 78° 46' 42" or nearly 2' more than the 

 above; the same calculation applied to the returning observations would 

 give a still more erroneous result 78° 53' 10" or 8^' more than that deduc- 

 ed from Purkyul. The change of rate in the watch, which was greater 

 than 1 had ever known it in the same period, prevents my placing any con- 

 fidence in either of these results. The detail will have its use if it inspire 

 a cautious dependence on Chronometers, and a salutary suspicion of their 

 results under the most favorable circumstances. No watch that I have 



