390 THE INTELLECTUAL RISE IN ELECTRICITY. 



predictions of the weather. Besides all this, he made the 

 remarkable electrical experiments and discoveries now to 

 be described. 



Most of the long and arduous researches whereby physi- 

 cal science has become established have been undertaken, 

 not for the purpose of ascertaining results previously un- 

 known, but in the hope that their outcome would afford 

 support for some preconceived and favorite hypothesis. 

 In this way, as I have already pointed out, Gilbert was 

 led to his magnetic and electric investigations, trusting to 

 find in them corroboration for his cosmical theory. So 

 Cabseus undertook similar studies in the hope of eliciting 

 evidence which would break down, not only Gilbert's con- 

 ception, but the Copernican doctrine generally. So ob- 

 servation of the magnetic spectrum and its phenomena 

 resulted in the mentally conceived spirals of Descartes and 

 their percolation through and grouping about the mag- 

 net. So, in another field, the alchemists established the 

 science of chemistry through their futile experiments in 

 search of the transmutation of metals. 



In dealing with the ancient and mediaeval philosophers 

 we have seen that they seldom narrowed their observation 

 down to specific matters. Their treatises, as a rule, were 

 on the Nature of Things De Natura Rerum from the 

 days of Lucretius onward, and there was a time when a 

 writer, such as St. Isidore, might reasonably compress all 

 that was known about everything in natural philosophy, 

 both celestial and terrestial, into a very moderate-sized tome. 

 As sublunary things, however, became familiar and com- 

 monplace, philosophical speculations began to change, and 

 finally, during the sixteenth century, the fundamental 

 hypothesis was one pertaining, not to the nature of things 

 in general, but to the nature of the extra-mundane regions 

 and of the worlds moving therein. Hence to the three 

 great theories of Ptolemy, Copernicus, and Tycho Brahe 

 were added sometimes new hypotheses, sometimes new 

 supporting arguments, just in proportion as new knowl- 



