1837.] 



Account of the Trevandrum Observatory* 



57 



The extreme dimensions (i. e. including the verandahs) are seventy- 

 eight feet in length, east and west, and thirty-eight feet in breadth, 

 north and south j these, although small compared with most other 

 public Observatories, will, it is hoped, prove amply sufficient for all 

 useful purposes. 



The hill on which the observatory is erected is a solid mass of late» 

 rite, in which granite is largely disseminated, and is so hard as to be 

 penetrated with great difficulty ; but little depth was therefore required 

 for the foundations, which are accordingly only sunk one foot below the 

 surface, on which the granite bases for the instruments are erected— 

 this surface is by excavation three feet below the general level of the 

 soil outside, and three and a half feet below the floor of the observing 

 rooms. On it is erected, nearly to the height of the floor, but without 

 contact with it, or with the surrounding walls, a solid mass of granite 

 masonry for each instrument, consisting of large pieces of stone 

 clamped together ; that in the transit room («) is ten feet long, by four 

 feet broad ; that in the circle room (c) ten feet square, and that in the 

 centre room (6) six feet square. The walls are two feet in thickness, 

 built of squared stones of laterite, and afford a clear height in the ob- 

 serving rooms of seventeen feet. The meridional openings are three 

 in number, each two feet wide, and extend across the building to within 

 three feet of the ground on each side— they are well secured and con- 

 veniently laid open by shutters covered with canvas, and painted, and 

 having slips of copper over the abutments. The roof is flat, and on 

 the centre of it is erected a wooden circular building, of nine feet 

 diameter, with a revolving dome which covers a solid pillar of granite, 

 coming up through the centre room without contact with floor, roof, or 

 any part of the building, and terminating about three feet above the 

 flat roof. This pillar is two feet in diameter at the top, and four feet at 

 bottom, and is erected on the granite base of six feet square — the pillar 

 consists of five pieces in the form of a frustrum of a cone. Two other 

 revolving domes of the same size are placed over the circular rooms at 

 the southern corners of the Observatory, which are square turrets of 

 solid masonry. The roof or terrace is conveniently approached by two 

 stair-cases outside the building, and winding round the turrets. The 

 verandahs are divided into small rooms as sleeping apartments, com- 

 puting offices, library, &c. 



The clear dimensions (inside) of the transit room {a) are 14 ft. by 12. 



Do. of the circle room (c) 14 ft. by 12. 



Do. of the centre room (6) , 20 ft. by 12, 



The breadth of the verandah is eleven feet. 



