NATURAL AND PHYSICAL SCIENCE, 1700-1800 315 



June, 1752, that he made his famous kite experiment, which showed 

 that lightning is really an electrical phenomenon, since a Leyden 

 jar can be charged from the skies, and at the same time proved that 

 atmospheric and machine-made (frictional) electricity are one and 

 the same thing. This daring experiment was performed also in 

 Europe at about the same time by others, and marks one of the 

 greatest triumphs of science in any age, for it simplified and to a 

 great extent explained one of the oldest and most awe-inspiring 

 phenomena of nature. Furthermore, by correlating the thunder- 

 bolts of Zeus and the shocks of a Leyden jar with the sparks of an 

 electrical machine, and even with those from a cat's back, it tended 

 mightily to inspire confidence in natural philosophy and to lessen 

 correspondingly the universal dread of unseen, mysterious, and 

 supposedly supernatural, powers or influences. Other important 

 work in electricity was done in this century by Beccaria in Italy, 

 Canton and Symmer in England, and many others. 



THE BEGINNINGS OF MODERN IDEAS OF THE EARTH. The 

 eighteenth century saw important progress also in biological 

 subjects, although the word biology was not yet born, and 

 zoology and botany, even, were still undifferentiated and closely 

 associated with geological knowledge under the broad and hospi- 

 table Aristotelian term "natural history." Physiology meanwhile 

 retained its close connection with its parent medical science, its 

 logical relations to zoology and botany being generally unrecog- 

 nized. Inquiries were, however, on foot destined, as we can 

 now see, to bring about changes, namely, to differentiate natural 

 history into geology, botany, and zoology and, finally, to integrate 

 the two latter sciences into one greater than either, viz. biology. 



It must have occurred to the thoughtful reader of the foregoing 

 pages that the four elements of the Greeks and their followers 

 have by this time lost their primitive character, and become 

 highly complex compounds or combinations of phenomena. Air, 

 for example, by the end of the eighteenth century was proved to 

 be a mixture of various elements and compounds, to possess weight 

 and to exert pressure, to have no part in abhorrence of vacua, and 

 to be the seat of marvellous aqueous and electrical phenomena. 



