156 



Terrestrial Magnetism. 



JVo. 16. Paoli, Indiana, Lat. 38° 35' JV., Lon. 86" 25' W. Sept. 20, 1840. 



The close agreement of the results of these two needles, will 

 undoubtedly surprise experimenters on magnetism. They are 

 much nearer to identity than at first I had hoped to bring them. 

 The desirable object has been accomplished partly by a fine in- 

 strument, and partly by peculiar manipulations, which, when I 

 have perfected, I shall communicate to the public. 



