1843.] DIPPING NEEDLE. 3 



The unusually severe gales which then prevailed, com- 

 pelling us successively to put into Weymouth and Torbay, 

 we were prevented reaching Falmouth until the 5th of 

 February ; here I had been directed to swing the ship in 

 order to determine the amount of local attraction ; I had 

 also to receive and fit Fox's Dipping Needle, and obtain 

 final results on shore with Hansteen's Needles. These 

 latter experiments were conducted at the house of Robert 

 Were Fox, Esq., a gentleman to whom our Service and 

 the whole scientific world are deeply indebted ; and I 

 must not omit to acknowledge the kind assistance derived 

 on this occasion from the exertions of Capt. Ellice, com- 

 manding the Packet Establishment, who immediately 

 directed the boats and masters of the packets in port to 

 attend and aid our operations. 



In the ordinary duties which will be required hereafter 

 from every ship of war supplied with the compasses 

 adapted by the Committee of the Royal Society, assistance 

 from other vessels will scarcely be needed ; but in instances 

 where the Dipping Needle and other delicate instruments 

 are to be observed on the quarter-deck, and the results 

 of vessels equipped as the ' Samarang ' to be regarded of 

 authority, it is imperative that the ship be reduced to the 

 same condition as she would be when such observations 

 are to be made at sea ; that all chance of error may be 

 removed, or means pursued to arrive at data by which 

 any may be corrected. These observations referring to 

 the magnetic dip, intensity, and variation of the compass, 

 must be taken throughout the voyage from a fixed point ; 

 prior to sailing, therefore, the ship is to be reduced to her 

 sea footing ; that is to say to that state in which she would 



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