MAGNETIC TERM-DAY OBSERVATIONS 



U. S. COAST SURVEY OFFICE, CAPITOL HILL, WASIIIMiTON, D. C. 



Latitude, 38 53' 8". Longitude, 77^ 0' 11" (5A. 7m. 1.) wort of Greenwich. 



DIFFERENTIAL OBSERVATIONS OF DECLINATION IN 1851. 



The instruments used were declinometer No. 22, United States Coast Survey ; and from 

 and after June 18, declinometer No. 3, United States Coast Survey. The observations were 

 taken in the cellar of one of the Coast Survey buildings. Increasing telescopic readings denote 

 an easterly movement of the north end of the magnet of declinometer No. 22, but the reverse 

 motion for the magnet of declinometer No. 3 ; the first direction is inferred from the observed 

 diurnal movement. 



The following tables contain the scale readings. 



MARCH 10 and 20, 1851. 



