184 THE INTELLECTUAL RISE IN ELECTRICITY. 



carry the tooth beyond the magnet, and then the magnet 

 would attract the protruding portion of the next succes- 

 sive tooth, which he probably imagined would be brought 

 nearer to it than would the rapidly-retreating face of the 

 tooth which had just passed. He states that the tooth 

 came alternately to the north and the south portion of the 

 magnet, and there was alternately attracted and repelled ; 

 but the pictures of the machine which appear in the vari- 

 ous old manuscript copies of the letter do not accord with 

 this explanation. He also adds a small ball, which falls 

 from one tooth to the other as the wheel rotates; and possi- 

 bly he supposed that the movement of this ball would add 

 something to the momentum of the wheel. Of course the 

 contrivance never could have worked. But then, paper 

 inventions often have that failing, and a large and goodly 

 company of imitators, walking in Peregrinus' footsteps, 

 are even now constantly finding this out. The law which 

 asserts that two and two make four, and no more, at all 

 times, and in all places, and that it is not given to man to 

 create anything whatever, has never been suspended in 

 favor of any mechanism, no matter how expensive or in- 

 genious, not even when it meets the approval of persons 

 of superior consequence, financial and otherwise, in the 

 community. Not having fully realized this fact ourselves 

 at the end of the nineteenth century, we may perhaps look 

 with some lenience upon the similar misapprehension of 

 Peregrinus six hundred years ago. 



Let me now recapitulate the foregoing remarkable 

 achievements. Peregrinus discovered and differentiated 

 the poles of the magnet. He revealed the law that unlike 

 magnetic poles mutually attract. He showed how to 

 detect the magnetic poles and demonstrated that in even- 

 part or fragment of a divided magnet the two poles persist. 

 He proved that not only is the iron needle attracted by 

 the lodestone, but that it will assume definite inclined or 

 angular positions when brought into proximity thereto. 

 Thus he, for the first time, disclosed the state of strain 



