262 INDUCTION AND DEDUCTION. 



atiou or deduction by means of induction, tliat is, through the combin- 

 ation of his conceptive or imaginative facultj' ; and his labor consists 

 in this, that, in conformity with the rules of experimental art, he shall 

 call into action the mediums or the substances which seem adapted to his 

 purpose, and from the reactions or phenomena which come to light, 

 draw a conclusion as to the existence or non-existence of the fact sought 

 for ; he contrives, it may be said, a series of trials, which, in their final 

 result, give the direction to his deduction. 



The difficulty lies for him herein, that the route to the fact he is seek- 

 ing is to him completely unknown ; for were it known, the conclusions 

 of the understanding would lend themselves to his aid. He is, there- 

 fore, necessitated to abide entirely by the iihenomena which his tenta- 

 tives furnish him, since these are the characters which guide his imagin- 

 ative power in its combinations. 



The remarkable discovery of ozonized oxygen in a chemical way by 

 Schonbein, affords one of the simplest examples of iuductiv^e processes. 

 Schonbein had found that, by the transmission of electrical sparks, the 

 atmospheric air acquires new properties, of which the most remarkable 

 consists in a i^owerful combination faculty of its oxygen, till then 

 unknown 5 in such air a number of bodies (silver, for instance) are 

 oxydized, on which the oxygen in air not electrified is without any 

 influence. Now, how came Schonbein to conclude thereupon, that phos- 

 phorus, by being slowly burned in air, would bring about the same 

 condition in the air as did the electric spark ? This conclusion was 

 based upon the fact that the air after electrification and after con- 

 tact with phosphorus smelled precisely alike ; the scenting principle 

 in the air, at the same time, had been found by Schonbein to pro- 

 duce the same effects. The similarity of a sensible property, of a scent, 

 led therefore to the inference of the origin and existence of a like sub- 

 stance, ozone, in tsvo processes in their nature entirely different. lu 

 this combination of ideas, had the guidance been left to the understand- 

 ing, it is highly probable that the discovery would have been imx)eded 

 by it; for to the understanding the fact of the origin of a substance 

 endued with the highest oxydizing powers, through or near a body 

 which, like phosphorus, is in the highest degree oxydizable, would have 

 ai)peared wholly improbable. 



One of the most important of Faraday's discoveries furnishes an 

 example of a more complex induction. 



Oersted had, through an electrical current, induced magnetism in 

 metallic conductors ; the problem wh ich Faraday proposed to himself was, 

 the reverse, to generate by means of a magnet an electrical current ; 

 it was directed to the production of a phenomenon, and since its law 

 and the way to its discovery were unknown, could only be solved in the 

 experimental, that is, in the inductive manner. The phenomenon once 

 known in all its relations, could then first become the subject of a 

 deductive scrutiny, and the contrast of the inductive labor of Faraday 



