1866.J Astronomical points of Central Asia. 47 



The weight which is to be attached to these corrections, must de- 

 pend on the degree of exactness which regulates the scientific labours 

 of the brothers Schlagintweit ; but unfortunately, in the volume that 

 has been issued, this consideration is not dwelt on, that is to say, the 

 probability of errors in the determinations is nowhere alluded to. ^The 

 determinations themselves are not particularised minutely enough, to 

 enable us to estimate their value. 



In order to judge of the correctness of these labours, we bring for- 

 ward some examples. Thus, in the determinations of Le in Ladak, 

 the error which should be expected in the latitude would amount to 

 30 //# . The longitude of Le was determined by the transfer of one 

 chronometer which was rated at Simla on the 15th May, at Le on the 

 17th September, at Srinagar the 24th October; the longitudes of 

 Simla and Srinagar are known. The rate of the chronometer should 

 have been deduced from the longest transfer occupying 162 days, from 

 which, in the main result, a considerable error was to be expectedf 

 amounting to no less than 7 7 .5. Further an error has crept into the 

 calculations of the brothers Schlagintweit which, when corrected, will 

 alter their result by 8' (instead of 77° 14' 6" it should be 77° 22' 5" 

 east of Greenwich) . The correction of the chronometer was determined 

 on the Karakoram pass on the 9th of August ; by its action from 

 Simla (15th May) to Srinagar (24th October) the longitude of the 

 pass was determined at 77° 30' 4". But corrections of the chrono- 

 meter at Le were also obtained on the 11th July and 17th Septem- 

 ber, according to which the determinations of the Karakoram pass is 

 found to be 77° 39'' 5" or, otherwise, differing by 9'. 



* The latitude of Le was determined twice by polar heights. 



11th July, ...., 34° 7'5 



16th September, 34° 9'2 



Mean, 34° 8'3 



According to Cunningham, 34° 9'1 



Moorcroft, 34° 9'3 



f The chronometer was rated in the Observatory of Calcutta in March, 

 1855 atad April, 1857 (pp. 98 and 102). From this it must appear, that the 

 probable 24 hourly disturbance of the chronometer on the spot would not be 

 less than its. In the longitude of Le, also, one can suspect an error of at 



least ~ S ' 3 '- — ± 29s. From Simla to Le is a journey of 125 days, from 



162 

 Le to Srinagar 37 days ; whole duration of the journey 162 days. 



