MAGNETIC TERM -DAY OBSERVATIONS 



MAGNETIC OBSERVATORY IN THE SMITHSONIAN GROUNDS, WASHINGTON, D. C. 



Latitude, 38 53' 14". Longitude, 77 1' 10" (5h. 8m. 5s.) west of Greenwich. 



DIFFERENTIAL OBSERVATIONS OF DECLINATION IN 1854 AND PART OF 1855. 



The observations were obtained by means of Mr. Charles Brooke's automatic photographic 

 registration of magnetometers, and as described by Captain J. H. Lefroy, E. A., director of the 

 magnetical observatory at Toronto, Canada. 



The traces were supplied with time and declination scales, and the readings were tabulated. 

 The correction for torsion amounts in maximo to 0.1, and has hence been neglected. The un- 

 certainty in reading off amounts to twice that amount. One division equals one minute of arc. 

 The time scale may be considered correct to the nearest half minute. 



Increasing scale readings denote a westerly movement of the north end of the magnetic bar. 



MAT 26 and 27, 1854. 



