518 THE SENSORIAL FUNCTIONS. 



that they are felt by the same percipient being. 

 A colour has no sort of resemblance to a sound ; 

 nor have either of these any similarity to an 

 odour, or a taste, or to the sensations of heat, or 

 cold. But the mind, which receives these in- 

 congruous elements, has the power of giving 

 them, as it were, cohesion, of comparing them 

 with one another, of uniting them into combina- 

 tions, and of forming them into ideas of external 

 objects. All that nature presents is an infinite 

 number of particles, scattered in different parts 

 of space ; but out of these the mind forms indi- 

 vidual groups, to which she gives a unity of her 

 own creation. 



All our notions of material bodies involve that 

 of space ; and we derive this fundamental idea 

 from the peculiar sensations which attend the 

 actions of our voluntary muscles. These actions 

 first give us the idea of our own body ; of its 

 various parts, and of their figure and movements ; 

 and next teach us the position, distances, magni- 

 tudes, and figures of adjacent objects. Com- 

 bined with these ideas are the more immediate 

 perceptions of touch, arising from contact with 

 the skin, and especially with the fingers. All 

 these perceptions, variously modified, make us 

 acquainted with those mechanical properties of 

 bodies, which have been regarded by many 

 as primary or essential qualities. The per- 

 ceptions derived from the other senses can only 



