216 GENERAL CONDITIONS- OF SCIENTIFIC RESEARCH. 



Society, that Picard in 1670 had measured with great 

 accuracy the length of a eertain portion of a meridian line 

 in France. He then made a second attempt and succeeded. 

 In consequence of similar reasons a scientific investi- 

 gator has sometimes to pause and consider whether the 

 state of science is sufficiently advanced to enable him to 

 verify a particular hypothesis or complete a proposed 

 research. The difficulty offered by the intrinsic import- 

 ance of a discovery, though second in magnitude to this, - 

 is often very great, and the discovery of new principles in 

 science requires an unusual combination of ability and 

 circumstances. Many think that great discoveries are 

 made all at once, and the accounts of them, as usually 

 given in books, confirm that impression ; but such is rarely 

 the case. It is true that the correct idea or hypothesis, 

 when it does occur to one's mind, does sometimes come 

 all at once; but in nearly all cases a great many false 

 hypotheses are imagined and tested before the correct one 

 is thought of. We must also remember that an hypothesis 

 does not become a discovery until exhaustive research 

 completely proves it to be correct ; he therefore is most 

 the discoverer who proves the truth. It is usually much 

 more difficult to find a new general principle in science 

 than to ascertain its quantitative relations. The discovery 

 of electro-magnetism, for example, was less easy to effect 

 than the subsequent finding of the law of its variation 

 according to distance. Many discoveries, however, are so 

 comparatively easy that even an advanced student may 

 make them. The rapid extension of organic chemistry 

 during the last thirty years has been largely due to re- 

 searches made by young chemists under the superinten- 

 dence of experienced investigators. Until an hypothesis is 

 verified it remains uncertain ; in a research, even at the 

 eleventh hour, our view may be found to be wrong ; and it 



