170 GENERAL CONDITIONS OF SCIENTIFIC RESEARCH. 



and in obedience to the laws of nature, including those 

 of his own organisation ; #nd if he thinks otherwise ^as 

 he often does) he only arrives at confusion or error. 

 6th. Even the period at which he may discover new know- 

 ledge, is almost entirely beyond his power to control, 

 because the ability to evolve new truths depends upon 

 the prior possession of certain other truths, which may 

 or may not then be known to him ; he cannot discover 

 truths for the discovery of which the necessary condi- 

 tions are not sufficiently developed, and he must leave 

 such discoveries for future generations to accomplish. 

 7th. As he cannot determine the period of discovery of 

 new truths, the order of such discovery is largely beyond 

 his control, and he must be willing to follow where nature 

 leads, and to discover in the assigned route that which is 

 possible in the then existing state of scientific knowledge. 

 8th. And as his mental evolution and material well-being 

 largely depend upon the development of new scientific 

 knowledge, he must be content to work and wait, and to 

 evolve his own destiny by means of the uncontrollable 

 spirit of activity implanted within him, which he must 

 satisfy, and cannot suppress. 



CHAPTER XVII. 



STARTING-POINTS OF RESEARCHES AND DISCOVERIES. 



THE actual date of a discovery, especially of a great one, is 

 frequently indefinite, a discovery being rarely made all at 

 once. Existing knowledge and new ideas form the usual 

 starting-point of discovery ; the finding of one truth often 

 depends upon the previous discovery of another. ' Ampere, 

 who was the first to observe the rotation of a magnet upon 



