LECTURE II. 63 



ceived bv our senses, and seem even to 

 elude our conceptions. Is it not then 

 most philosophical to acknowledge our 

 ignorance on these points, and to speak 

 of* what we do know, the properties of 

 the different species of substances in na- 

 ture. Thus we seem to be acquainted with 

 the properties of the aggregate forms of 

 that substance which is cognizable to the 

 eye and touch, and which we then call 

 matter ; we seem to be assured of the 

 existence, and to know something of the 

 properties, of a subtile substance which 

 pervades all nature ; and if we are allowed 

 to know any thing, we surely may be ad- 

 mitted to know the properties of our own 

 'minds. 



How diversified are our perceptions, 

 how admirably are they adapted to our 

 wants and gratifications ! for all beauty 

 of prospect, all melody of sound, all va- 

 riety of odour j^^ must by the eye of reason 

 be perceived to result from the masses 

 or molecules of surrounding matter, being 

 in various states of motion or of rest : 



