CHARACTER OF THE EXPERIMENTALIST. 221 



research disclose the laws of nature they embody. Ex- 

 haustive classification in all possible orders is out of the 

 question, because the possible orders are practically in- 

 finite in number. It is before the glance of the philoso- 

 phic mind that facts must display their meaning, and fall 

 into logical order. The natural philosopher must there- 

 fore have, in the first place, a mind of impression- 

 able character, which is readily affected by the slightest 

 exceptional phenomenon. His associating and identifying 

 powers must be great, that is, a single strange fact must 

 suggest to his mind whatever of like nature has pre- 

 viously come within his experience. His imagination 

 must be active, and bring before his mind multitudes of 

 relations in which the unexplained facts may possibly 

 stand with regard to each other, or to more common facts. 

 Sure and vigorous powers of deductive reasoning must 

 then come into play, and enable him to infer what will 

 happen under each supposed condition. Lastly, and 

 above all, there must be the love of certainty leading 

 him diligently and with perfect candour, to compare his 

 speculations with the test of fact and experiment. 



Freedom of Theorizing. 



It would be a complete error to suppose that the great 

 discoverer is one who seizes at once unerringly upon the 

 truth, or has any special method of divining it. In all 

 probability the errors of the great mind far exceed in 

 number those of the less vigorous one. Fertility of 

 imagination and abundance of guesses at truth are among 

 the first requisites of discovery ; but the erroneous guesses 

 must almost of necessity be many times as numerous as 

 those which prove well founded. The weakest analogies, 

 the most whimsical notions, the most apparently absurd 

 theories, may pass through the teeming brain, and no 



