A HISTORY OF SCIENCE 

 BOOK III 



MODERN DEVELOPMENT OF THE PHYSICAL 

 SCIENCES 



WITH the present book we enter the field of the 

 distinctively modern. There is no precise date 

 at which we take up each of the successive stories, 

 but the main sweep of development has to do in each 

 case with the nineteenth century. We shall see at 

 once that this is a time both of rapid progress and of 

 great differentiation. We have heard almost nothing 

 hitherto of such sciences as paleontology, geology, and 

 meteorology, each of which now demands full attention, 

 ntime, astronomy and what the workers of the 

 r day called natural philosophy become wonder- 

 fully diversified and present numerous phases thai 

 would have been startling enough to the star-gazers 

 philosophers of thr earlier epoch, 

 us, for example-, in thr fieM of astronomy, Her- 

 schel is able, thanks to his ]>erfeete<1 lelescope, to 

 cover a new planet and then to reach out into the 



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