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variation of the magnetic needle. 
If it be equal, the oscillations of the same dipping needle 
would be performed, circumstances as to temperature and 
“ local attraction” being the same, in equal spaces of time in 
both places; but if the magnetic power in either place be 
greater, the oscillations of the needle would there be quicker. 
The number of vibrations of a horizontal needle, performed 
in a certain space of time in Greenland, is to the number per- 
formed in an equal space of time in England as 5 to 6, each 
longer vibration in England being performed in 5 seconds, and 
in Greenland in 6. No alteration was observed in the time 
required for each vibration, whether the temperature was high 
or low, but I think in a low temperature the vibrations per- 
formed by the needle before it stopped were fewer. 
5. The anomaly of variation bears a certain proportion to 
the dip of the needle, being greatest where the dip is greatest, 
diminishing as the dip decreases, and disappearing altogether 
on the magnetic equator. 
Captain Flinders, ascertained, that the medium error or 
anomaly for 8 points deviation of the Investigator's head, on 
either side of the magnetic meridian, was very nearly — of 
the dip, .05 the decimal expression of which, he considered to 
be the common multiplier to the dip, for obtaining the radius 
of error at any situation in the southern hemisphere; and .053 
to be the common multiplier, from England to the magnetic 
equator. This, however, can only be correct within certain 
limits, as on the magnetic pole, where the anomaly would 
probably be equal to the dip, or 90°, the decimal multiplier 
would require to be increased to 1.0. Hence it has been 
suggested, by an officer on board one of the vessels now in 
search of a north-west passage, that in those parts of the 
globe where the dip is 90°, the compass needle ’would pro- 
