INDUCTIVE EPOCH OF HIPPARCHUS. 199 



In this sense, therefore, the Hipparchian theory 

 was a real and indestructible truth, which was not 

 rejected, and replaced by different truths, but was 

 adopted and incorporated into every succeeding 

 astronomical theory ; and which can never cease to 

 be one of the most important and fundamental 

 parts of our astronomical knowledge. 



A moment's reflection will show that, in the 

 events just spoken of, the introduction and esta- 

 blishment of the theory of epicycles, those charac- 

 teristics were strictly exemplified, which we have 

 asserted to be the conditions of every real advance 

 in progressive science; namely, the application of 

 distinct and appropriate Ideas to a real series of 

 Facts. The distinctness of the geometrical concep- 

 tions which enabled Hipparchus to assign the orbits 

 of the sun and moon, requires no illustration ; and 

 we have just explained how these ideas combined 

 into a connected whole the various motions and 

 places of those luminaries. To make this step in 

 astronomy, required diligence and care exerted in 

 collecting observations, and mathematical clearness 

 and steadiness of view exercised in seeing and 

 showing that the theory was a successful analysis 

 of them. 



Sect. 3. Discovery of the Precession of the 

 Equinoxes. 



THE same qualities which we trace in the researches 

 of Hipparchus already examined, diligence in col- 

 lecting observations, and clearness of idea in repre- 



