266 



HISTORY OP ASTRONOMY.. 



ticut. The principal south meridian mark is situated on 

 the bare summit of a hill two miles distant, at an eleva- 

 tion of less than two degrees above the level of the transit 

 circle. 



i** 



'.UITMOUTII COLI.i:.:K OB8EBVATOBY. 



The observatory is of brick, with double walls fifteen 

 inches thick, inclosing a six-inch space of air between 

 them ; and, as the cornice and the partitions are also of 

 brick, and the roof covered with tin, it is nearly fire- 

 proof. The building consists of a central two-story ro- 

 tunda, 20 feet in diameter, with three one-story wings 

 one on the east, measuring 35 by 16 feet, and the other 

 two on the north and south, each 20 by 16 feet. The 

 foundations of the walls and of the piers all rest upon 

 the solid rock sienitic gneiss at depths varying from 

 zero to 14 feet below the underpinning. The lower cir 



