Rev. Mr Scoresby on the Uniform Permeability of 



eating a temporary diminution in their energy, by mere proxi- 

 mity, of nearly ^^gth of their power. 



With a pair of three-feet bars (A), tempered throughout, and 

 magnetised some weeks previous to the experiment, not any per- 

 manently deteriorating influence by juxtaposition, without con- 

 tact, was perceptible ; and the temporary or local deterioration 

 appeared to be considerably less. When these two bars, at the 

 distance of nearly 9 feet from the compass, were arranged paral- 

 lel to each other, 4 inches apart, they produced a deviation of 

 exactly 5°, whilst only :^th of an inch asunder (edge from edge), 

 the deviation was not perceptibly different ; but, when placed 

 over each other, but still :^th of an inch asunder, the power di- 

 minished to 4° 50' ; and, when placed in contact upon each other, 

 it was reduced to 4° 45'. When the magnets were again sepa- 

 rated to the distance of 4 inches, their deviating power was 

 4° 58', indicating a very small loss of magnetic energy. 



The following Table exhibits the action of these magnets se- 

 parately, and also in juxtaposition, 4 inches asunder, at differ- 

 ent distances from 1 to 6 yards : 



With these well-tempered bars, placed in juxtaposition 4 



• The first column of this division represents the sum of the mean devia- 

 tions of the two preceding divisions ; the second column the sum of the tangents 

 of the two preceding divisions, while the third column exhibits the angles 

 corresponding to these tangents. 



