334 Kev. Mr Scoresby 07i the Uniform Permeability^ ^c. 



Before Contact, and After Contact 



1, 3" 45' 3* 34' 



1,2, 6 35 6 14 



1,2,3, 9 26 9 6 



1,2,3,4, 11 46 10 26 



1,2,3,4,6, 14 4 13 



1,2,3,4,6,6, 16 64 14 30 



The transient diminution of energy by contact and juxta- 

 position, was strikingly exhibited on separating the bars after 

 the contact. Whilst they remained in contact, in the arrange- 

 ment figured at o, their directive power was indicated by a de- 

 viation of 12° 30', as just stated ; but, when removed to posi- 

 tion a, each bar being ^^th. of an inch asunder, the deviation 

 was 12° 54' ; fth of an inch asunder, it was 13° 54' ; an inch 

 asunder it was 14° 15' ; and two inches apart it was 14<° 48'. 



From these, and several other series of analogous experiments, 

 it appeared, that in all cases there was an advantage gained as 

 to power, whenever dissimilar poles were placed in contact, over 

 the corresponding arrangement with the bars separated, as a 

 comparison of experiment h with c ; of h with i ; of m with n, 

 clearly exhibit ; — and that a loss of power was sustained, by 

 bringing into contact similar poles under a like form of arrange- 

 ment, as appears from the comparison of a with o. And it was 

 further ascertained that the advantage gained by favourable 

 contact (that of dissimilar poles), was the greatest with the 

 softest bars ; whilst the loss sustained by unfavourable contact 

 (that of similar poles), was also the greatest in such bars, — the 

 hard tempered bars being, on the one hand, less susceptible of 

 benefit from induced magnetism, and, on the other hand, less 

 liable to injury from the contact of similar poles. 



(To be concluded in next Number.) 



