PEREGRINUS 1 DISCOVERIES. 185 



and stress existing in the medium surrounding the mag- 

 net, which, acting upon the light needle, compelled it to 

 set itself in the direction of lines of force proceeding from 

 the stone. Thus he first exhibited the condition of the 

 magnetic field. He saw, though dimly, that the directive 

 quality of the freely-suspended lodestone depended, not 

 alone upon some inherent virtue of the stone, but upon an 

 external influence acting upon it an influence which he 

 regarded as emanating from the celestial sphere. He found 

 the position of the poles on a globular magnet, and recog- 

 nized the magnetic meridians upon its surface. He first 

 perceived the correct way of measuring magnetic strength. 

 He discovered the mutability of the magnetic poles, and 

 that the poles of a weaker magnet could be reversed or 

 obliterated by the inductive action upon them of a stronger 

 magnet. 



He invented the first mariner's compass which could be 

 constantly used to steer by as we steer by it now, instead 

 of being employed merely to indicate the diiection of the 

 Pole star ; the first compass having a fiducial or "lubber's" 

 point and a graduated scale : the first compass capable of 

 being used to measure azimuth or bearing : the first com- 

 pass having a pivoted needle the prototype of all electri- 

 cal measuring instruments in which such an indicator is 

 employed : and, if he did not actually recognize the re- 

 tarding effect of a magnetic field upon a non-magnetic body 

 (such as silver or copper), and combine such non-magnetic 

 metal with the needle of his instrument in order to dampen 

 or check its natural vibrations and so to bring it quickly 

 to rest at its indication, he at least perceived that the mag- 

 netic field had 110 directive force upon such a body, and 

 that therefore it could be employed as an additional index 

 under the control of the magnetized needle. Finally, 

 he first suggested the conversion of magnetic (electric) 

 energy into mechanical energy in an organized machine 

 and to do useful work ; and thus he proposed the first 

 magnetic (electric) motor. 



