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The waves beating against the rocks or shore > yea, or 

 against one another, will occasion the same appearance, 

 and often yield -a long course of light the whole night. 

 In the Brasils the shores often seem all on fire by th** 

 waves dashing against them, hi general, the thicker 

 and fouler the seas are, the more of this light they 

 afford. In many places the sea is covered with a 

 yellowish matter like saw-dust, which seems to be the 

 excrement of some sea-animal. The water where this 

 is found gives more light, upon moving, than any other. 



Some parts of the northern seas are covered with this 

 for several leagues together, and this is often luminous 

 all over in the night, though not stirred by any thing 

 moving through it. 



In the gulph of Venice the water is luminous only 

 from the beginning of summer till the end of harvest 

 This light is most copious in places abounding with sea- 

 grass, especially when any thing moves the water. One 

 iiled a flask with this water ; but it emitted no light till 

 it was stirred in the dark. When this "was strained 

 through a fine cloth, the cloth shone in the dark, but not 

 the water. This light consisted of innumerable lucid 

 particles. When some of this sea-grass was taken up, 

 there were above thirty of these particles on one leaf, 

 one of which, when it was shaken, fell off. It was as 

 fine as an eye-lash, and about as long. Viewed with a 

 microscope it appeared to be a worm or maggot, consist- 

 ing of eleven rings, with as many ma mill on the sides 

 instead of feet. Their whole bodies were lucid, though 

 least so when at rest. In spring they confine themselves 

 to the sea-grass : but in summer they are dispersed all 

 over the sea, and mostly on the surface. When this sea 

 sparkles more than usual, it is the sure sign of a storm ; 

 and this proceeds from the greater agitation of the 

 worms, already sensible of the approaching change. 

 Hence it is clear, that the glittering of this sea, in a 

 ship's course, is occasioned by these worms, which pro- 

 bably is the case in some other seas also ; and they are 

 certainly the cause of the light in the Pinaa-Marina, 



