89 



mode of testing the quality would secure the best steel, and 

 the best instruments, instead of risking a quality such as he 

 had shown in one of the navy needles, which was not fit for 

 a coach spring ! Measures, indeed, had been commenced 

 some years ago, after he had publicly exhibited some of his 

 improvements in compasses, for improving those of the navy. 

 He had shown his plans near four years ago to the gentlemen 

 appointed for this object, so far as his investigations had then 

 proceeded ; but nothing effectual, he believed, had yet been 

 done. Introductory to his process for the determination of 

 the temper and hardness of steel, he should state that the 

 principle had long been held that the harder the steel the 

 more permanent the magnet. The truth of this he had tried 

 in many experiments, and had always found it so. And now 

 he came to the practical rule for knowing the hardness by 

 the magnetic tenacity. If it was true that the hardest steel 

 made the most permanent magnets, then it was only necessary 

 to obtain a knowledge of the degree of permanency as the 

 measure of the hardness. [He then re-magnetized two 

 needles of similar quality, but different in hardness, and 

 compared the weights which they respectively bore after 

 being subjected to the action of the test bar ; — when one had 

 lost little, the other the whole.] Hence, he came to this 

 conclusion — that the former was the hardest, which on trial 

 by other means, was proved to be the fact. He then applied 

 the test of the deviation of the compass, and showed also by 

 this means that the hardness of the steel might be discovered 

 with great minuteness : so that of 100 bars or plates of the 

 same kind, as to quality, they could easily be arranged by 

 the aid of the test-bar and compass, in the order of their 

 respective degrees of hardness. 



Mr. Morton inquired whether the bars must be always of 

 the same diameter or of the same bulk, in order to carry out 

 the experiment perfectly. 



