VISION. 447 



source. Not only has it given us extensive com- 

 mand over the objects which surround us, and 

 enabled us to traverse and explore the most dis- 

 tant 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 remotest con- 

 fines of creation. As the perceptions supplied 

 by this sense are at once the quickest, the most 

 extensive, and the most varied, so they become 

 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 illustra- 

 tions of his reasonings ; and it is also from the 

 same inexhaustible fountain that the poet draws 

 his most pleasing and graceful, as well as his 

 sublimest imagery. 



The sense of Vision is intended to convey to 

 its possessor a knowledge of the presence, situ- 

 ation, and colour of external and distant objects, 

 by means of the light which those objects are 

 continually sending off, either spontaneously, or 

 by reflection from other bodies. It would ap- 

 pear that there is only one part of the nervous 

 system so peculiarly organized as to be capable 



