149 
‘¢the world knows; and it is certainly not too much to say that, of 
what we know to-day of the distribution, intensity and periodic 
and secular changes of terrestrial magnetism, we are indebted quite 
as much to Bache as to any other one man.,’’ 
In connection with his colleague, Courtenay, then Professor of 
Mathematics in the University of Pennsylvania, he undertook an 
elaborate investigation of the value of the dip and the horizontal 
intensity of the earth’s magnetism at several places in the United 
States, the results of which were published in two extended memoirs 
printed in the Zransactions of the Society.* 
On his thirtieth birthday, July 19, 1836, Bache was elected Pres- 
ident of Girard College, then about to be put into operation under 
the provisions of the will of Stephen Girard; and, receiving in- 
structions to visit Europe in order to examine similar institutions 
there, he resigned his chair in the University and spent two years 
abroad. While in Europe he found opportunity to determine the mag- 
netic dip and horizontal intensity at twenty-one stations, with the 
same apparatus and by the same methods which he had employed in 
America; the results of which determinations he communicated to 
the Society in a paper entitled, ‘‘ Observations of the Magnetic 
Intensity at Twenty-one Stations in Europe.’’ + These observa- 
tions were made with the view of ascertaining the relative direction 
and strength of the magnetic force in Europe and America by the 
comparison of parallel series of observations in the two countries 
with the same instruments. ‘They also served, in most instances, to 
settle with greater precision than had previously been attained the 
relative magnetic condition of the stations at which they were 
made. 
It was while waiting for the College to go into operation that 
Prof. Bache entered into active codperation with the great under- 
taking of the British Association, ‘‘ to determine, by contempora- 
neous observations at widely separated points, the fluctuations of the 
magnetic and meteorological elements of the globe. This codper- 
* “Observations to Determine the Magnetic Dip at Baltimore, Philadelphia, New York, 
West Point, Providence, Springfield and Albany,” Trans. Amer. Phitos. Soc. (New Series), 
V, 209, 183-4. 
“‘On the Relative Horizontal Intensities of Terrestrial Magnetism at Several Places in 
the United States, with the Investigation of Corrections for Temperature and Comparisons 
of the Methods of Oscillation in Full and Rarefied Air,” Trans. Amer. Philos. Soc. (New 
Series), v, 427, 1836. 
+ Trans. Amer. Philos. Suc. (New Series), vii, 75, 1840 ; Proceedings Amer. Philos. Soc., i, 185. 
