INDUCTIVE AFFINITY. 205 



that position, which may be indicated by inscribing cl in the circle 

 which represents the chlorine atom. The other atom of the 

 particle B, or the hydrogen, comes therefore to be the seat of 

 the opposite, or zincous pole, and is marked z. Of the two 

 atoms forming the polarizable molecule A of the zinc, the ex- 

 terior atom which is in contact with the acid has thereby zincous 

 attraction developed in it, and becomes the zincous pole, while 

 the interior becomes the chlorous pole, as indicated in both by the 

 inscribed letters. This polar condition of the zinc and acid 

 particles A and B must be supposed the necessary and im- 

 mediate consequence of their simple contact. 



But each of these particles throws a train of particles of its 

 own kind into a similar state of polarity 5 A, the contiguous 

 particles E and I of the zinc, and B the contiguous particles 

 C and D of the acid. For cl of A becoming a chlorous pole, 

 developes near it an opposite, or zincous poles in zn of E, 

 and a chlorous pole in c/, the more remote extremity of E ; 

 in the same manner as the austral pole of a magnet de- 

 velopes, by induction, a boreal and austral pole in a piece of 

 soft iron applied to it. And as the induced magnet, thus 

 formed, will react upon a second piece of iron, and render it 

 also magnetic, so the polarized particle E, renders I similarly 

 polar. The polarized condition of the particles C and D ; of 

 the acid is produced by B in the same manner. But as 

 in a series of induced magnets (Fig. 5.), the magnetism ac- 

 quired diminishes with the distance from the pole of the original 

 magnet, so in trains of chemically polarized molecules, such 

 as A, E, I and B, C, D, the amount of polarity developed 

 in each molecule will diminish with the distance from the 

 sources of induction A and B ; I being polarized to a less 

 degree than E, and D than C. 



In the electrical theory of the voltaic circle as modified by 

 Mr. Faraday, the zinc and hydrochloric acid are equally sup- 

 posed to have a polarizable molecule. The polarity is also 

 developed in these molecules by their approximation or contact. 

 The molecule of hydrochloric acid is supposed to contain the 

 positive and negative electricities which possess contrary 

 powers, like the two magnetisms ; and are in combination and 

 neutralize each other, in the non-polar condition of the mo- 

 lecule. But the contact of zinc causes the separation of 

 the two electricities in the acid molecule, its atom of chlorine 

 next the zinc becoming negative, and its atom of hydrogen 



