^ MEASURE OP A DEGREE ON THE COROMANDEL COAST. 



down to the water, to be 21 '166 feet above t]ie sea. Which, 

 Btlded to the above, give 69'963 feet for the perpendicu- 

 lar height of the top of the stand above the level of the 

 sea. 



Now the top of the race-stand was determined by level- 

 ling to be 31 "25 feet above the north extremity of the base; 

 wliich, taken from the other, leaves 38*713 for the north 

 extremity of the base above the sea, which extremity be- 

 ing, by the table, 22*96 feet above the south extremity, 

 * we shall have 15*753 feet from the perpendicular height 

 pf the south extremity of the line above the level of tJie 

 sea; and from this height the length of the base has been 

 reduced. 



The angles of elevation and depression were taken by the 

 circular instrument, from a mean of several observations, 

 and the errour of co'hmation was corrected by turning the 

 transit over, and the horizontal plate half round. But the 

 weather was rather dull during the whole of these opera- 

 tions. 



Major Lambton then proceeds to give the particulars of 

 the measurement of his base line, commencing in lat. 13° 

 00' 29*59" N., and extending 40006*4418 feet south-west- 

 erly, making an angle of 10 36' with the meridian. 



Commencement of the operations from the hase. The large 

 theodolite. 



?roperest sta- After the completion of the base line, there remained 

 lions selected, i^othing of importance to be done until I received the large 

 instrument, which arrived in the beginning of September. 

 1 had however made an excursion down the sea coast, as far 

 as Pondicherry, for the purpose of selecting the properest 

 stations for determining the length of a meridional arc. 

 This and the measurement of a degree at right-angles to 

 the meridian 1 considered as the first object of this work: I 

 accordingly lost no time in proceeding to accompli§^h these 

 desiderata. 

 Theodolite. The instrument above alluded to was made by Mr. Cary, 



and is in most respects the same as that described by Ge- 

 neral Roy in the Philosophical Transactions for the year 

 1790, with the i^iprovements made afterwards in the micro.< 



scopes. 



