THE ELECTRIC EFFLUVIUM. 309 



of the musk which was mingled with the mortar in the. 

 building of the Mosque of St. Sophia in Constantinople. 



How then does such an effluvium attract? Does it set 

 the air in motion, and is the air-current followed by the 

 attracted bodies ; or are the latter directly drawn? If an 

 air-current moves the objects, how can a minute diamond 

 of the size of a chick-pea pull to itself so much air as to 

 sweep in a corpuscle of relatively large dimensions, seeing 

 that the air is drawn by only a small portion of one end 

 of the stone? Clearly it is not the air which is moved, for 

 then clearly the attracted body must stand still or move 

 more slowly before coming in actual contact with the 

 amber, on account of the heaping-up of the air on the sur- 

 face and its rebounding after collision. And, furthermore, 

 if there be a variation in the character of the effluvia, if 

 they go forth rare and return dense (as with vapors), then 

 clearly the body would begin to move a little after the be- 

 ginning of the application of the electric. But and here 

 is the first statement of that marvelous speed of transmis- 

 sion which, in the telegraph and telephone, annihilates 

 distance "when rubbed electrics are suddenly applied to 

 the pivoted pointer instantly the pointer turns.'' 



New ideas now crowd fast one upon the other. The in- 

 creased attractive power of the electric, as the attracted 

 body approaches it, is recognized; the motion of the body 

 is seen to be quickened, "the forces pulling it being 

 stronger." At once Gilbert perceives the similarity in this 

 respect between electric and magnetic attraction, and it 

 seems that almost of necessity he must be led to interpret 

 this as a most untoward result, tending to show the iden- 

 tity of the very phenomena which he was hoping to differ- 

 entiate. But note how he dealt with it. Not only, he says, 

 is this quickened motion, this augmenting force, true of 

 the magnetic and electric attractions, "but of all natural 

 motions." The great generalization of the correlation, not 

 only of magnetic and electric attractions with one another, 

 but with the other forces of the universe, is here suggested 



