SIR GILBERT BLANE. 333 



of the mind, it follows, that what is called the vis 

 inertice of matter, is not a resistance to a change 

 from rest to motion or from motion to rest, but a 

 resistance to acceleration or retardation, or to 

 change of direction. If it should be alleged, that 

 any given particle or portion of matter is carried 

 along by value of the motion of the planet to which 

 it belongs, it may be answered, that the earth or 

 any other planet is nothing more than a congeries 

 of such particles, each of which must possess a share 

 of the same energy which animates the whole 

 mass." 



" I have already acknowledged my ignorance of 

 the manner in which stimuli in general operate, 

 and that this must be admitted as an ultimate fact 

 in nature. But the operation of the will through 

 the nerves, seems involved in double obscurity; 

 for as it depends on the nature of thought, it can- 

 not be made a subject of experimental investigation. 

 For this reason I shall decline the enquiry, as not 

 being adapted to the ends of this Society : and it 

 seems impossible for human sagacity to penetrate 

 the connection of matter with sensation and volition. 

 All such attempts have consisted of abortive and 

 unsatisfactory inferences drawn from hypothetical 

 assumptions. The properties of different bodies, in 

 relation to each other, appear to be the only proper 

 subjects of experimental reasoning; for, in their 

 relation to the mind, they are only the effects, 

 perhaps the remote effects, of their intimate nature 

 upon the senses ; and we may venture to affirm that 

 human reason can no more fathom the connection 



