06 



Proceedings of the Asiatic Society. 



[March, 



of Public "Works, and 200 feet to the south of a salient point on the 

 Coast. These measurements are taken from a block survey of Cha- 

 tham Island, dated 20th May, 1865, which has been furnished by 

 Lieutenant dimming, R.E; the Executive Engineer at Port Blair. 



The station is marked by a circular pillar of masonry rising a few 

 inches above the gronnd level, on the surface of which there is a stone 

 with a mark showing the exact point over which the Astronomical 

 Circle was centered. The pillar has been covered with a" cairn of 

 stones, into which a marble slab has been built, containing the fol- 

 lowing inscription : — 



This stone marks the site of the observatory erected in 1861, on 

 Chatham Island, tor determining the position of Port Blair. 



The observations were taken by Mr. Nicolson, of the Survey De- 

 partment, WITH AN ALT-AZIMUTH INSTRUMENT, nAVING A VERTICAL CIRCLE 



of 3 feet in diameter. they were reduced in the office of the great 

 Trigonometrical Survey of India. 



results. 



Latitude, 11° 41' 13' 



Longitude east of Greenwich, 92 42 44 



The longitude was determined by 202 observations of lunar zenith 

 distances, and 29 culminations. 



I may here observe that in the Admiralty Chart which was com- 

 piled from the Surveys of Lieutenant Blair and Captain Moorsom in 

 3.789-90, and was revised by Lieutenant Heathcote in 1853, the longi- 

 Seconds of Results by Moon Culminations, 



Date. 





Result. 





Date 









Result. 



5 th June, 1862, 



• • 





4651 



4th February, 



:i 







44-85 



6th „ 



• • 



... 



29 03 



5th 



?> 





i> 



• • 



,. 



54-03 



8th „ „ 



.. 



... 



50-00 



6th 



j> 





5» 



• • 



, , 



50.00 



9th „ 



Ml 



,,, 



64-08 



7th 



» 





;> 



• • I 



, 



55-69 



13th „ „ 



... 



... 



43-74 



9th 



?> 





53 



, . 



• 



71-17 



14th „ „ 



.. 



... 



37-23 



10th 



a 





)} 



• • 



,. 



63-89 



5th November, 1862, 



• • 



50-14 



27th 



)i 





)i 



• • < 



, 



43-09 



5th January, 1863 



,.. 



.. 



3775 



28th 



i» 







• • « 



. 



51-11 



10th „ ' „ 



... 



• • 



5941 



2nd March, 



1863, 



• • 



, 



52 17 



11th „ 



.. 



• • 



61-42 



2nd 



April, 



55 





• • 1 



, 



62-27 



30th „ „ 



• • 



• • 



43-51 



3rd 



;i 



5> 





• • « 



, 



52-88 



31st „ „ 



• • 



.. 



47-12 



4th 



it 



» 





• • I 



• 



50.13 



1st February, „ 



.. 



• • 



45*21 



6th 



Si 



5? 





• • 1 



• 



56-73 



2nd „ „ 



• • 



.. 



34-83 



7th 



it 



i$ 





• • 1 



. 



67-25 



3rd „ „ 



•* 



•■ 



43-32 





















Mean 



5S5 6& 



10 m 



50-64 *. 













