AN EXPOSITION AND CRITICISM. 309 



stance, or Solidity physical. This may be called Ultimate or AbsO' 



lute Incompressibility. 



2. The attribute of being contained in space implies 



(a.) Mobility or the possibility of motion and consequently of rest, 



(6.) Situation ox position. 



II. The qualities of matter, which are partly objects of perception 

 and partly causes of sensation, may be named Secundo- Primary. 

 They suppose the primary, because they have a relation to motion in 

 space, being all only various forms of resistance to our locomotive 

 energy ; but on the other side they are modes of pressure affecting 

 our sentient organism. They may be divided either from b. physical 

 or from a psychological point of view. 



1. Physically their divisions correspond to the different external 

 sources of resistance, which are three. 



(a.) Codttraction is either a. that of Gravity^ originating the rela- 

 tive qualities of heavy and light, or y8. that of Cohesion, originating 

 the relative qualities of hard and soft, solid and fluid, viscid and 

 friable, retractile (elastic) and irretractile (inelastic) &c. 



(5.) Repulsion gives rise to the counter qualities of a. the relatively 

 compressible and incompressible, /3. the resilient (elastic) and irresilient 

 (inelastic). 



(ci) Inertia, combined with Magnitude and Cohesion, comprises 

 the counter qualities of the relatively moveable and immoveable. 



2. Psychologically they are divisible in accordance (a.) with the 

 degrees of resistance offered, (5.) with the mode in which the resist- 

 ance may affect the sentient organism. The former is their objective 

 or quasi-primary aspect, the latter their subjective or secondary ; 

 but I do not carry this distribution into detail. 



III. The remaining class, which are called the Secondary Qualities 

 of matter, are, in so far as they belong to bodies, merely the powers, 

 which these are supposed to possess, of producing affections in our 

 sentient organism. I use the expression Secondary qualities, however, 

 for these subjective affections themselves; and in this sense thei' 

 varieties depend principally on the differences of the different parts of 

 our nervous apparatus {Reid's Works, Note D.) 



With regard to perception in general then it will be observed, that 

 in every act of perception I am conscious at once of myself as perceiv- 

 ing and of something which is not myself as perceived (I. p. 288 ; 

 Jteid's Works, p. 747, and passim). That this is the fact of which 



