Variation of the Magnetic Needle. 69 



• The variation observed by Doctor Williams at Rutland, 

 in Vermont, leads to the same result. His observations at 

 that place were 



1789 April 17 7° 3' W 



1810 May 19 6 4 



1811 Sept. 9 6 1 



Whence he concludes, that the magnetic variation at Rut- 

 land, for twenty two years past, has been decreasing at the 

 annual rate of 2' 49"-5. 



III. In May, 1819, the late Professor Fisher of Yale Col- 

 lege, commenced a series of observations on the declination 

 ot the needle, which were continued, from time to time, un- 

 til April, 1820. The instrument employed was a variation 

 compass, which had been recently constructed by a skillful 

 artist, and had all the appendages necessary for the nicest az- 

 imuth and altitude observations. From Mr. Fisher's notes, 

 we collect the following results, being the means of a great 

 number of trials at different hours of the day. 



Mean, .... 4.° 25.' 42 



Remark. — It appears from the foregoing observations, that 

 the declination of the needle at New Haven, in the years 

 1819 and 1820, was less than had been observed at either 

 of the places mentioned in the first of the above articles. 

 The least declination given by the Hon. Mr. De Witt, was 

 in August 1818, and amounted to 5°. 45', which is about 

 1°. 20' greater than the mean of the observations of Profes- 

 sor Fisher. 



