102 A HISTORY OF 



many a poor Greenlander has fatally experienced." Thus are these 

 amazing ice-mountains launched forth to sea, and found floating in 

 the waters 'round- bath-' th*e * poles. It is these that have hindered 

 mariners from discovering the extensive countries that lie round the 

 Sout.li P<ile w ; -tOicr -that Ipnibdbly block up the passage to China by the 



* *?* i.sVrt.x * 



I will conclude this chapter, with one effect more, produced by the 

 altness of the sea; which is the luminous appearance of its waves in 

 the night. All who have been spectators of a sea by night, a little 

 ruffled with winds, seldom fail of observing its fiery brightness. In 

 some places it shines as far as the eye can reach ;* at other times, 

 only when the waves boom against the side of the vessel, or the oar 

 dashes into the water. Some seas shine often ; others more seldom ; 

 some, ever when particular winds blow ; and others within a narrow 

 compass ; a long tract of light being seen along the surface, whilst all 

 the rest is hid in total darkness. It is not easy to account for these 

 extraordinary appearances : some have supposed that a number of lu- 

 minous insects produced the effect, and this is in reality sometimes 

 the case; in general, however, they have every resemblance to that 

 light produced by electricity ; and, probably, 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 

 accident to discover. Our progress in the knowledge of nature is 

 slow : and it is a mortifying consideration, that we are hitherto more 

 indebted for success to chance than industry. 



CHAPTER XVI. 



OP 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 ; without which they would soon putrefy, 

 and spread universal infection. If we look for final causes, here in- 

 deed 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 nature would shortly be 

 at an end. Nothing would then be left alive but swarms of ill-formed 

 creatures, with scarcely more than vegetable life ; and subsisting by 

 putrefaction. Were this extensive bed of waters entirely quiescent, 

 millions of the smaller reptile kinds would there find a proper retreat 

 to breed and multiply in : they would find there no agitation, no con- 

 cussion in the parts of the fluid to crush their feeble frames, or to 

 force them from the places where they were bred : there they would 

 iiultipiy in security and ease, enjoy a short life, and putrefying thus 

 again, give nourishment to numberless others, as little worthy of ex 

 istence as themselves. But the motion of this great element, effccla 



* Boyle, voL i. p. 294. 



