ARTICLE IX. 



Observations of the Magnetic Intensity at twenty-one Stations in Europe. By 

 A. D. Bache, LL. D., President of the Girard College for Orphans^ one of the 

 Secretaries of the American Philosophical Society, SfC, SfC. Read March 6, 

 1840. 



The following observations of intensity and dip were made during a visit to 

 Europe in 1836-7 and 1837-8, directed by the Trustees of the Girard College 

 for Orphans, The special objects of my journey admitted of only an occasional 

 attention to the observations in question, which I did not attempt unless when 

 time and circumstances were generally favourable to their execution. The 

 stations are twenty-one in number; three in Great Britain, and the others on 

 the continent. At some of the places the magnetic elements are so well known 

 from numerous observations that my results can add but little to the informa- 

 tion already before the public; at others, few observations have been made, and 

 my determinations assume a higher relative importance. Those of the former 

 class will serve, by their accordance with the results of other observers, to give 

 a general confidence in the results of the latter, and will especially assist in 

 connecting the European stations with those in the United States, which formed 

 one principal object of experiments, the results of which I propose to commu- 

 nicate to the society in a separate memoir. 



At all the places but three the horizontal intensity and dip were observed, 

 and at two the total intensities were, in addition, compared by the statical me- 

 thod of Professor Lloyd. The observations for the horizontal intensity were 

 made by oscillating horizontal needles in a rarefied medium, in the manner ex- 



