304 THE INTELLECTUAL RISE IN ELECTRICITY. 



end, and so shows the attractive effect. Before he devised 

 this he seems to have made the electric draw to itself the 

 attracted object bodily ; but he found that the attractive 

 force, in some substances, was too weak to overcome both 

 inertia and frictional resistance, and the pivoted needle, 

 the position of which a very small drawing force could 

 easily disturb, was therefore contrived. 



This is the first of all instruments depending upon 

 amber-electricity. And again what is it essentially but 

 the compass needle? Not the freely-movable magnet 

 needle turning itself under the influence of the earth's 

 magnetic field and yielding itself to the earth's attraction, 

 but simply a freely-movable needle of any substance turn- 

 ing itself under the influence of the electric field of the 

 rubbed amber and yielding itself to the amber's attraction. 

 Here was the first electrical invention beyond the mariner's 

 compass, the adaptation of the same physical means (the 

 balanced needle rotating on its pivot) to the recognition of 

 the fact of a field of force. Gilbert had shown how that 

 colossal magnet the earth governed the compass needle, 

 and how the same control was exerted upon the needle by 

 the miniature earth the terrella. Also he had shown that 

 the excited amber would attract any substance provided 

 the latter were light in weight and so within its exertable 

 strength. A step further, and the excited glass or sulphur 

 and the compass needle the two things that lay respec- 

 tively at the beginning of the new advance and at the 

 culmination of the old came together : and the needle, 

 (immaterial whether magnetic or not, so long as it were 

 light and easily controllable,) moved in response to the 

 call of the electric. 



By means of this instrument, Gilbert says, he detected 

 his electrics, and thus suggests the amount of patient 

 labor which he brought to the task. How many sub- 

 stances he procured, rubbed and carried to his needle, only 

 to see it remain motionless, we can but surmise. In the list 

 which he gives of things which are non-electrics, because 



