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than one of the navy needles which was made of tempered 

 steel.] On comparing his soft steel bar with the tempered 

 navy needle, he found that his soft steel would lift the same 

 or even a greater weight ; hence he concluded that the steel 

 of the naval needle was bad. But he also applied another 

 test — the test of tenacity for the magnetic principle. He 

 took a very powerful small magnet which he called a test bar, 

 and applied the magnetised pieces of steel to it, similar poles 

 of the test bar and of the bars to be tested being laid toge- 

 ther. The quantity of power left showed the degree of 

 tenacity which each had. [Dr. Scoresby then performed the 

 experiment again. He put the first needle spoken of before 

 (the inferior navy needle) on the magnet, a piece of glass 

 intervening, and found on taking it away that the magnetic 

 principle had entirely vanished. He then placed the second 

 navy needle upon the test bar without the intervention of the 

 ^lass, and on taking it off, it, too, was powerless. He lastly 

 applied a needle of his own, and on taking it off it appeared 

 not to have suffered from contact, as it still lifted a key about 

 three times the weight which either of the navy needles could 

 lift in their highest energy.] The first inference he drew 

 from this was, that his bar was of a very superior quality 

 of steel to the others, and the next was that one of the 

 needles was utterly incapable of performing the function 

 intended. In truth neither of them was sufficient for the ob- 

 jects for which they were used, as they could not adequately 

 accomplish their purposes. The improvement of such sea 

 compasses, therefore, was an object of national importance. 

 To entrust a first-class ship of war, worth £100,000, per- 

 haps, with a crew of several hundreds of men, to such 

 instruments as these, involved a heavy charge of blame some- 

 where. He had now shown the meeting the vast superiority 

 even of his single or ordinary needles over those of the 

 navy : he had shown elsewhere, as well as here, that his 



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