120 NATURAL HISTORY. 



except it be joined with sound, hath no great opera 

 tion upon sounds : for whether the air be lightsome 

 or dark, hot or cold, quiet or stirring, except it be 

 with noise, sweet smelling, or stinking, or the like ; 

 it importeth not much ; some petty alteration or dif 

 ference it may make. 



227. But sounds do disturb and alter the one the 

 other : sometimes the one drowning the other, and 

 making it not heard ; sometimes the one jarring and 

 discording with the other, and making a confusion ; 

 sometimes the one mingling and compounding with 

 the other, and making an harmony. 



228. Two voices of like loudness will not be 

 heard twice as far as one of them alone : and two 

 candles of like light, will not make things seen twice 

 as far off as one. The cause is profound ; but it 

 seemeth that the impressions from the objects of the 

 senses do mingle respectively, every one with his 

 kind : but not in proportion, as is before demon 

 strated : and the reason may be, because the first 

 impression, which is from privative to active, as from 

 silence to noise, or from darkness to light, is a greater 

 degree than from less noise to more noise, or from 

 less light to more light. And the reason of that 

 again may be, for that the air, after it hath received 

 a charge, doth not receive a surcharge, or greater 

 charge, with like appetite as it doth the first charge. 

 As for the increase of virtue, generally, what pro 

 portion it beareth to the increase of the matter, it is 

 a large field, and to be handled by itself. 



