GEODETIC OBSERVATIONS. 215 



During the early part of this season (1886-87) Lieutenant Burrard 

 continued the latitude observations Avith the zenith section near the 

 meridian of 80°, observing at five stations and so extending the arc 

 to about latitude 20° N. The longitude operations were resumed 

 in Southern India, and the following arcs were measured : — 



1. Madras — Bangalore. 



2. Bangalore — Nagarkoil (near Cape Comorin). 



3. Madras — Nagarkoil. 



4. Nagarkoil — Mangalore. 



5. Madras — Mangalore. 



6. Bellary — Mangalore. 



7. Mangalore — Bombay. 



Nos. 1 and 5 were revisions of the work executed in 1872-73 and 

 rejected (as mentioned above) owing to a fault in the telescopes, and 

 No. 7 the arc which was left incomplete in 1876-77. 



Three of the old arcs in Southern India were revised in addition 

 to four new ones being measured. The season's measurements tended 

 to confirm a curious geodetic fact that the plumb-line round the 

 coasts of India deviates in the direction of the sea. They were also 

 satisfactory in showing a diminution in the circuit errors which was 

 probably as small as can be expected, while the value obtained for 

 arc No. 7 differed only by 0*023 of a second from the value of the 

 same arc as measured in 1876-77. 



Operations were resumed in 1889-90 in the Punjab, Baluchistan, 

 and Central India. Seven arcs were measured, including the 

 revision of one formerly measured in Baluchistan, and the measure- 

 ment of a cross-arc, Agra-Karachi. 



