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Obfervations o« Me M A G N E T I C FLUID. By Captain 

 O'BRIEN DRURY, of the Royal Navy. Communicated 

 by Co/o«e/ VALLANCEY, M.R.I.A. 



X H E magnetic fluid and its phasnomena are not lefs flngular Read Nov. 

 than obfcure, and have too long engaged the attention of philo- 

 fophers for me to offer an hypothefis on the fubjed ; I mean 

 only to fpeak to a matter of fad, which I am led to believe 

 may be ferviceable to navigation^ efpecially fhould the variation 

 of the compafs ever be made ufe of as a method for afcertaining 

 the longitude. 



It is not neceflary to enter into a detail of experiments to 

 prove the exiftence of the magnetic Jluid, which circulates con- 

 tinually around and through a magnet, as it is fully demon- 

 ftrated by the arrangement of iron fiUngs thrown on glafs, placed 

 over a magnet. 



Experience fhews us that the needle of a compafs, as well 

 as all other magnets, whether artificial or real, perpetually lofes 

 fomething of its magnetic power, which often produces a dif- 

 ference exceeding a point ; and I am well convinced that the great 

 errors in Jhip-reckonings ^''^octcd more frequently from the incor- 

 redlnef'j of the compafs than from any other caufe. 



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Steel 



