206 Influence of Terrestrial Magnetism on Iron. 



lutely striving against the weakness of the body. He was 

 confined to bed for a few days at last; spoke much and affec- 

 tionately to his children when pain did not prevent him ; 

 looked forward with calmness and hope to his last struggle ; 

 expressed in the clearest terms his simple trust in his Savi- 

 our alone, and at last gently fell asleep to be for ever with the 

 Lord, whose works he had so ardently admired on earth, and 

 in whose atoning blood he trusted for acceptance with his 

 God. 



He married early in life and has left a numerous family, 

 for whom we regret to learn he has not been able to make 

 any provision. His eldest son has already distinguished 

 himself as a naturalist. He was employed in that capacity 

 by the late Earl Derby, on board the expedition sent by him 

 round the world ; and after his return he wrote the account 

 of the voyage of the " Rattlesnake " in a manner which has 

 justly earned him a high reputation, both as an observer and 

 a describer. He is now absent as Government Naturalist on 

 board the " Herald," which lately sailed to carry out and 

 complete the exploration of the Eastern Archipelago and 

 Southern Pacific, and we trust in due time, by means of this 

 expedition, to have a large accession to our knowledge from 

 the pen of Mr John Macgillivray. 



Influence of Terrestrial Magnetism on Iron, and the effect 

 that results from it upon the direction of the Compasses in 

 Vessels. 



The terrestrial globe may, like a magnet, exercise at a 

 distance its magnetising powers. If we hold vertically, or, 

 which is still better, in the direction of the dipping needle, a 

 bar of soft iron about a yard in length, we find that it ac- 

 quires two poles, a north pole at its lower, and a south pole 

 at its upper extremity. The existence of these two poles is 

 manifested by the attractive and repulsive action exercised 

 by the two extremities of the bar upon the same pole of a 



