219, 



ON THE MAGNETIC DIP AT SEVERAL 



as at Springfield, in nearly the same latitude, but was surprised to find 

 it as follows. 



By needle No. 1, 71° 04'-5; by needle No. 2, 71° 05'-25 ; mean, 

 71° 04''S75. The above observations were made in a field not far 

 east from the state house, April 3, 1838, from eight to nine o'clock, 

 A. M., temperature 40°. Suspecting local attraction, I removed to a 

 wood, north west of the lunatic asylum, and went through with an- 

 other series, which gave the following results. 



Needle No. 1, 71° 04'-375 ; No. 2, 71° 05'-375 ; mean, 71° 04'-875, 

 as before. Time, ten to eleven o'clock: temperature 43°. As these 

 results agree identically, I will give the observations in full. 



No. of 

 Needle. 





Limb of 



Face of 

 Needle. 



Indication. 





Indication. 





Polarity. 



Instru- 



1st Experi- 



Mean. 



2d Experi- 



Mean. 







ment. 





ment. 





ment. 







r E 



E 



70° 55' 





70° 53' 







A J E 



^ i w 



W 



71 30 





71 27 







E 



70 45 





70 47 







W 



W 



71 25 





71 21 





1. < 

















- E 



E 



71 40 





71 45 







B <! W 



W 



70 24 





70 25 







E 



71 35 





71 39 







L w 



W 

 E 



70 22 



71 35 



71'' 04'-5 



70 18 



71 39 



71° 04'-875 



f 



r E 









A < 



E 



W 



70 32 





70 29 







W 



E 



71 38 





71 37 









W 



W 



70 28 





70 27 





2. < 

















r E 



R ^ E 



E 



71 00 





70 58 







W 



71 26 





71 31 







E 



70 45 





70 40 







W 



71 18 



71° 05-25 



71 22 



71° 05'-375 







71° 04'-875 



71° 04'-875 



As we cannot rely upon observations of this kind, but within a cer- 

 tain latitude of error, I consider the identity of the above results a mat- 

 ter of accident. In making the last observations, no reference was 

 made to the minutes of the first, lest an insensible leaning should be 

 given to the mind to make them agree. 



The latitude and longitude of the several places, except Cincinnati, 



