HISTORY OF < 



total darkness. It is not easy to account for these 

 extraordinary appearances : some have supposed 

 that a number of luminous insects produced the 

 effect, and this is in reality sometimes the, case ; 

 jn general, however, they have every resemblance 

 to that light produced by electricity, and proba- 

 bly arise from the agitation and dashing of the 

 saline particles of the fluid against each other. 

 But the manner in which this is done, (for we 

 can produce nothing similar by any experiments 

 hitherto made), remains for some happier acci- 

 dent to discover. Our progress in the knowledge 

 of nature is slow ; and it is a mortifying consi- 

 deration, that we are hitherto more indebted for 

 success to chance than industry. 



CHAPTER XVI, 



OF THE TIDES, MOTION, AND CURRENTS OF THE SEA ; 

 WITH THEIR EFFECTS. 



IT was said, in the former chapter, that the waters 

 of the sea were kept sweet by their motion, with- 

 out which they would soon putrefy, and spread 

 universal infection. If we look for final causes, 

 here, indeed, we have a great and an obvious one 

 that presents itself before us. Had the sea been 

 made without motion, and resembling a pool of 

 stagnant water, the nobler races of animated na- 

 ture would shortly be at an end. Nothing would 



