S68 Rev. Mr Scoresby on some of the Laws 



exactly in the proportion which the magnetism induced in 

 the iron bears to the actual energy of the magnet itself. The 

 relation of the induced magnetism with that of the inductive 

 energy being thus at one distance simply and experimentally 

 ascertained, the proportion of induction due to any other dis- 

 tance is as easily determinable. 



On this plan a series of experiments on the power of induc- 

 tion with a bar of soft iron of the same dimensions as the mag- 

 net, was made at a variety of distances from contact up to five 

 inches, together with two comparative series, at the same dis- 

 tances, with two other soft iron-bars of similar length and 

 breadth, but differing in thickness, one being ^^^^th of an inch 

 thick, and the other an inch, whilst the magnet itself was jth of 

 an inch thick. 



The following Table exhibits the mean deviation of both ends 

 of each iron-bar, in juxtaposition with the magnet, as placed at 

 17 different distances, the magnet, which was 13| inches long, 

 being uniformly at the distance of 24 inches from the centre of 

 the compass, where, by its sole action, it produced a deviation 

 of 18° 14'. 



Table of the Effects of Induced Magnetism on three different Bars 

 of Soft Iron, at various distances. 



