9^0 Rev. Mr Scoresby on some of the Laws 



3, 4, and 5 inches, the force at the distance of an inch being 

 called 100. 



In this method of determining the proportions of the mag- 

 netism induced, both with reference to the power of the magnet 

 made use of, and with respect to the distance of the bar from 

 the magnet, it was assumed that these proportions would be the 

 same at whatever distance from the magnet the compass era- 

 ployed for the deviations might be placed. In order to verify this 

 assumption, as well as to acertain the degree of consistency to 

 be expected in similar experiments, elsewhere made, another 

 series of deviations, under a similar arrangement, and with a 

 magnet and an iron-bar of the same dimensions as the former, 

 was observed some months after the foregoing deductions had 

 been calculated. The distance of the bars from the compass 

 was, in this instance, changed — being now 12 inches instead of 

 two feet. 



The following were the deviations and results obtained from 

 this series, as to the proportions of induced magnetism at the 

 different distances of 1, 2, 3, 4, and 5 inches; the magnet alone 

 producing a deviation of 61° 15^. 



Comparing the last two columns, we have a coincidence suf- 

 ficiently near to verify the assumed principles, — that the mea- 

 sure of the actual, as well as proportionate forces of induced 

 magnetism, is correctly derived from the tangents of the devia- 

 tions, and that the proportions are not dependent on, or influ- 

 enced by, the distance at which the compass is placed from the 

 magnet and iron-bar. The differences, indeed, in the ratio of in- 



