248 Intelligence and Miscellaneous Articles, 



meeting currents. The author does not mean to attribute the calm 

 lines in general to the spreading of a sheet of fresh water over the 

 salt water of the sea, but he thinks the general explanation is readily 

 developed from the observations and explanation in the foregoing 

 particular case. He supposes in general that in estuaries and chan- 

 nels of the sea, and in lakes and rivers, the water must often be 

 affected by various causes, such as tides, breezes, currents, and cir- 

 culation due to differences of heat, so as to be made to rise occasion- 

 ally at some places and to sink at others. Now along the line of 

 meeting and sinking of two opposing surface currents, all floating 

 objects carried by those currents will be collected together; and 

 there they will act as dampers, or floating breakwaters, for the small 

 ripple undulations. The slightest possible inequalities of the forces 

 of the two opposing currents will suffice to account for the great 

 sinuosities which the calm lines show. If there should happen to be 

 any oily scum thinly diffused on the surface of the water, this will be 

 brought together, along with seaweeds, &c, from a wide area, to the 

 line of meeting and descent of the two opposing surface currents ; 

 and to an oily film having been frequently noticed on the calm places, 

 though really brought to them in the way now suggested, the author 

 inclines to attribute the supposition that it is their cause ; but he 

 agrees that very possibly, too, an oily scum thus sometimes brought 

 together may cooperate with the seaweed and other floating objects 

 in resisting the propagation of the ripple. 



In the discussion which followed the reading of this paper, it was 

 remarked by members of the Society that, in drawing nets through 

 the sea near its surface for collecting small marine animals, they had 

 often found that these creatures were present in vastly greater abun- 

 dance in the calm lines than in the rippled sea ; and it was suggested 

 that, as the bodies of many of these contain oil, this, on their dying, 

 might be given off from their bodies, and might float on the surface, 

 and might cause the smoothness there observed ; and it was also 

 stated that shoals of herrings are much more abundantly met with 

 under the calm lines than at other parts of the sea. 



The author of the paper, in replying, pointed out that, if marine 

 animals giving off oil from their bodies were really the cause of the 

 calm lines, it would still remain as an unsolved question, and one 

 which would then be of great interest, Why should those animals be 

 found to congregate in long sinuous lines, extending often continu- 

 ously for miles over the surface of the sea ? He thought, however, 

 that the true state of the case would probably be, that the small 

 animals are brought together by the same currents which, according 

 to his supposition, collect the seaweed, leaves, and other floating 

 objects into lines, and that the animals, not wishing to descend with 

 the meeting currents into deep water, remain near the surface, and 

 that the herrings or other fishes congregate to the same lines in order 

 to feed on the smaller animals. — Proceedings of the Belfast Natural 

 History and Philosophical Society, May 7, 1862. 



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