OF NATURAL PHILOSOPHY. 85 



CHAP. II. 



OF THE ANALYSIS OF PHENOMENA 



(76.) PHENOMENA, then, or appearances, as the word 

 is literally rendered, are the sensible results of 

 processes and operations carried on among external 

 objects, or their constituent principles, of which they 

 are only signals, conveyed to our minds as aforesaid 

 Now, these processes themselves may be in many in 

 stances rendered sensible ; that is to say, analysed, 

 and shown to consist in the motions or other affections 

 of sensible objects themselves. For instance, the phe- 

 nomenon of the sound produced by a musical string, 

 or a bell, when struck, may be shown to be the result 

 of a process consisting in the rapid vibratory motion 

 of its parts communicated to the air, and thence to 

 oar ears ; though the immediate effect on our organs 

 of hearing does not excite the least idea of such a 

 motion. On the other hand, there are innumerable 

 instances of sensible impressions which (at least at 

 present) we are incapable of tracing beyond the 

 mere sensation; for example, in the sensations of 

 bitterness, sweetness, &c. These, accordingly, if 

 we were inclined to form hasty decisions, might bo 

 regarded as ultimate qualities ; but the instance of 

 sounds, just adduced, alone would teach us caution 

 in such decisions, and incline us to believe them 

 mere results of some secret process going on in 

 our organs of taste, which is too subtle for us to 

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