CH. xxxn. ASTRONOMY. 297 



CHAPTER XXXII. 



SCIENCE OF THE NINETEENTH CENTURY. 



Difficulties of Contemporary History Olbers Asteroids Encke's 

 Comet Biela's Comet Adams Leverrier Discovery of Neptune 

 Sir John Herschel Comets and Meteor -systems Improved 

 Telescopes Leverrier's analysis of Planetary Orbits. 



WE have now arrived fairly at the beginning of our own 

 century, and shall have to speak of events which happened 

 as it were but yesterday, and of men whom our grandfathers, 

 or even perhaps our fathers, have seen and known. How 

 are we to find our way through the mass of discoveries 

 which have been made in every science during the last 

 seventy years, or to make our choice among the number of 

 famous men whose names we meet with every day? We 

 must begin at once by recognising that it is impossible to 

 mention all, even of the leading points, of the science of 

 our time, and then we may try to learn a few of them, if we 

 do so with a clear understanding that we are leaving im- 

 portant gaps unfilled. 



There are two special difficulties which we must en- 

 counter in the history of this century ; first, we cannot 

 avoid mentioning the work of some living men, while at the 

 same time we omit others who are equally eminent ; and 

 secondly, we must speak of many subjects which are still, as 

 it were, on their trial, and which will not be finally settled 

 till they can be judged dispassionately by future generations, 



