400 THE SENSORIAL FUNCTIONS. 



to the physical laws of light, and that all its parts 

 are finished with that mathematical exactness which 

 the precision of the effect requires, and which no 

 human effort can ever hope to approach, — far less 

 to attain. 



To the prosecution of this inquiry we are farther 

 invited by the consciousness of the incalculable 

 advantages we derive from the sense of sight, the 

 choicest and most enchanting of our corporeal en- 

 dowments. The value of this sense must, indeed, 

 appear inestimable, when we consider of how large 

 a portion of our sensitive and intellectual existence 

 it is the intermediate source. Not only has it given 

 us extensive command over the objects which sur- 

 round us, and enabled us to traverse and explore 

 the most distant regions of the globe, but it has 

 introduced us to the knowledge of the bodies which 

 compose the solar system, and of the countless 

 hosts of stars which are scattered through the 

 firmament; thus expanding our views to the re- 

 motest confines of creation. As the perceptions 

 supplied by this sense are at once the quickest, the 

 most extensive, and the most varied, so they be- 

 come the fittest vehicles for the introduction of 

 other ideas. Visual impressions are those which, 

 in infancy, furnish the principal means of deve- 

 loping the powers of the understanding: it is to 

 this class of perceptions that the philosopher resorts 

 for the most apt and perspicuous illustrations of 

 his reasonings ; and it is also from the same inex- 

 haustible fountain that the poet draws his most 

 pleasing and graceful, as well as his sublimest 

 imagery. 



