THE NATURE OF THE ELECTRIC. 307 



versorium, although the flame certainly produces a heated 

 current, will cause the needle to turn. 



By any peculiar property of amber or special relation 

 between it and other bodies, because very many other sub- 

 stances partake of the same electric nature. 



By similitude or likeness, because all terrestrial things, 

 whether like or unlike, are attracted by the electric. 



Nor has the electric attraction any resemblance to the 

 drawing of moisture by plants, the purging of a morbid 

 humor by a drug, the removal of water from a stoppered 

 bottle when covered with a heap of wheat, or the mythical 

 sucking up of water by elephants' tusks. 



Then follows the list of solid non-electrics already given, 

 and to this are added many substances which either fall to 

 pieces or grow sticky by rubbing, such as pitch, soft resin, 

 camphor, galbanum, ammoniacum, storax, asa, gum ben- 

 jamin and asphalt um. 



Having thus cleared the ground negatively, Gilbert pro- 

 ceeds to draw his affirmative conclusion as to the physical 

 nature of the electric. The earth, he says, is made up of 

 two kinds of Matter ; moist and fluid, or watery, and dry 

 and firm, or terrene. Any given substance consists either 

 of both kinds of Matter or of a concretion of either kind. 

 Amber and jet are concretions of water so are all shining 

 gems and 'electrics generally have their origin in humor 

 or watery Matter. This humor can even be driven out by 

 heat and discharged as vapor. But electrics have certain 

 necessary physical characteristics ; namely, that they are 

 firmly concreted so that they shine on being rubbed, and 

 retain the u appearance and property of fluid" in a firm, 

 solid mass. These conditions present, they attract all 

 bodies, whether humid or dry, by a force which likewise 

 has its origin in the humor. 



The next step is to account for this attractive force. 

 The attraction of the magnet, it will be remembered, he 

 supposes to be due to its effused Form awakening an inert 

 Form in the drawn iron, so that the thing attracting and 



