AIM AND PROGRESS OF PHYSICAL SCIENCE. 369 



To the uninitiated, this science of ours is an accumula- 

 tion of a vast number of facts, some of which are con- 

 spicuous for their practical utility, while others are 

 merely curiosities, or objects of wonder. And, if it were 

 possible to classify this unconnected mass of facts, as was 

 done in the Linnean system, or in encyclopaedias, so that 

 each may be readily found when required, such knowledge 

 as this would not deserve the name of science, nor satisfy 

 either the scientific wants of the human mind, or the 

 desire for progressive mastery over the powers of nature. 

 For the former requires an intellectual grasp of the con- 

 nection of ideas, the latter demands our anticipation of a 

 result in cases yet untried, and under conditions that we 

 propose to introduce in the course of our experiment. 

 Both are obviously arrived at by a knowledge of the law 

 of the phenomena. 



Isolated facts and experiments have in themselves no 

 value, however great their number may be. They only be- 

 come valuable in a theoretical or practical point of view 

 when they make us acquainted with the law of a series 

 of uniformly recurring phenomena, or, it may be, only 

 give a negative result showing an incompleteness in our 

 knowledge of such a law, till then held to be perfect. 

 From the exact and universal conformity to law of natural 

 phenomena, a single observation of a condition that we 

 may presume to be rigorously conformable to law, suffices, 

 it is true, at times to establish a rule with the highest 

 degree of probability ; just as, for example, we assume our 

 knowledge of the skeleton of a prehistoric animal to be 

 complete if we find only one complete skeleton of a single 

 individual. But we must not lose sight of the fact that 

 the isolated observation is not of value in that it is 

 isolated, but because it is an aid to the knowledge of the 

 conformable regularity in bodily structure of an entire 

 species of organisms. In like manner, the knowledge of 



