MAGNETIC TERM-DAY OBSERVATIONS 



MAGNETIC OBSERVATORY ON D STREET NORTH, NEAR SECOND STREET WEST; AND 



FROM AND AFTER SEPTEMBER ON FOUR- AND- A-II ALE STREET WEST, NEAR 



AND NORTH OF PENNSYLVANIA AVENUE, WASHINGTON, D. C. 



D street observatory, lat. 38 53' 38" ; long. 77 0' 33" (5h. 8m. 2s.) W. of Greenwich. 

 4 street observatory, lat. 38 53' 31" ; long. 77 0' 44" (5/t. 8m. 3s.) W. of Greenwich. 



DIFFERENTIAL OBSERVATIONS OF DECLINATION IN 1852. 



The instruments used were declinometer No. 3, United States Coast Survey ; and after July 

 7, declinometer 20, Coast Survey No. 2. Increasing telescopic readings indicate a westerly 

 movement of the north end of the magnet for declinometer No. 3, and the reverse motion for 

 declinometer No. 2. 



The observations were taken in a wooden building temporarily erected in the yard of a house 

 occupied by Assistant Hilgard. 



MARCH 24 and 25, 1852. 



