tMHODUCTIOK. 



In conclusion, the realm of science, we have often thought, 

 resembles the vast expanse of ocean that lies glistening in the 

 morning sun ; not a breath of air disturbs the glassy surface ; 

 the vessels lie la/ily without movement or sign of life, and the 

 .re nil cluarly reflected in the water. Anon as we cast 

 our eyes out to sea, we perceive a shade darkening the horizon. 

 On it comes gradually widening and expanding till it spreads 

 like the shadow of an eclipse over the sea, throwing the water 

 into foam, spreading a mantle of blue where all was white, and 

 converting the lazy boats into birds of flight, so that each hip 

 could now enter on its voyage and go where it willed, while 

 previously it had to drift with tide and current. The ocean is 

 the sea of all knowledge ; th wind is the guiding law which 

 leads to the sources and ends of all truth ; and the vessels are 

 scientific theories which drift about with the tide. Sometimes 

 the name of a man may urge a theory along and give it pro- 

 minence, just as we sometimes see a tug boat towing a vessel 

 out of a harbor. But the steamer cannot always be with it, and 

 after the vessel is alone it is still at the mercy of the tide. The 

 ships may also make a great display and noise, they may hoist 

 flags and fire off cannon, they may challenge respect and attract 

 considerable attention, but they are only becalmed after alL 

 Which, then, of all the theories before the world, is that favour- 

 able wind ? 



