214 



MEASURING APPARATUS, &c. 



As to the operations by my predecessor, they are all before you in 

 the memoirs of this Society, excepting the last two bases, of which a detailed 

 account is found in my printed book. 



The first of these is the base of Takal Khera, which was measured by 

 Colonel Lambton on the ground, between the 6th January and 25th Janu- 

 ary, 1822. It was 37912.56, &c. feet, and consequently the daily progress 

 was 1896 feet nearly. 



The base of Seronj was measured by me on coffers, and was 38411.9 

 feet, it was completed in 20 days, i. e. between 24th November and 13th 

 December, 1824, the daily rate of progress was therefore 1920 feet. 



The base of Seronj computed from the triangulation between it and 

 Tahal Khera is 38412.16 feet, giving a difference of 0,26 feet in the whole 

 length, or .4288 of an inch in a mile. 



The Heeler base, as will be seen on reference to the Transactions of this 

 Society, was found from measurement to be 30806.176 feet, but the same 

 base deduced from the series of triangles connecting it with Takal Khera., 

 is only 30799.61, giving a difference of 6.57 feet nearly, or 13.516 inches 

 per mile. 



Thus then, it would seem, that the chain though generally correct, 

 is not of that trust-worthy nature that can induce an entire confidence in 

 the results it produces. A happy combination of errors may perhaps, 

 and generally will make them annihilate each other, but there is an uncer- 

 tainty attached to the reliance on such a contingency, which is any thing 

 but satisfactory in cases where the exact sciences are concerned. 



