

THE MAGNETIC FIELD OF FORCE. 207 



venture and a new spirit of enterprise ; new distribution 

 of wealth; new thought: in a word, the world, which 

 had halted for a dozen centuries, now moved onward, not 

 doubtingly and feebly as the invalid regaining health, 

 but with the might and majesty of its new and irresisti- 

 ble energy. 



Granted that it took great acts to do this, and that 

 nothing less than the discovery of the new continent, 

 the opening of the water-way to India and the circum- 

 navigation of the globe would have sufficed ; beyond them 

 all, making them all possible, lay the slender bit of mag- 

 netized iron, quivering on its pivot yet always looking to 

 the far north. 



Of the three methods of finding the magnetic poles which 

 Peregrinus describes, two, it will be remembered, are based 

 upon the position assumed by the needle or short bit of iron 

 when placed upon the surface of the spherical magnet. In 

 one instance, we are told to draw several lines upon the 

 globe corresponding in longitudinal direction to the needle, 

 the latter being placed at different points and permitted 

 freely to direct itself. These lines are found to be merid- 

 ians, and the poles of the stone are at their intersection. 

 In another* method, the needle is moved about on the 

 sphere, until a point is observed where it becomes in- 

 clined and stands perpendicular. 



Plainly, both of these methods reveal, as I have already 

 suggested, not a force drawing the iron to the stone, nor 

 yet anything happening in either stone or iron, but a pe- 

 culiar condition in the space immediately around the stone, 

 by reason of which the needle is moved both in a hori- 

 zontal and in a vertical plane, into a determinate position. 



The circumstances here are in all respects remarkable. 

 The compass needle was then supposed to point to the 

 Pole star under the influence of virtue from that star ; or, 

 as Peregrinus believed, under the effect of virtue from all 



