448 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. [22] 



a distribution would require too long a time to occur in the case in 

 question. If there is actually a very considerable uniformity in the dis- 

 tribution of the eggs, it is mainlj' caused by the circumstance that prob- 

 ably the spawning process along the coasts takes place within an area 

 embracing the Western Baltic, so that thence the mingling can take 

 place with greater ease. 



In our special case, the question is, whether actual thrusts or pushes 

 are made against the eggs in all directions? Simple waves have only 

 motions resembling that of the pendulum, ending perpendicularly to- 

 wards the surface ; they cannot, therefore, scatter the eggs horizon- 

 tally. The waves, however, are not simple waves, but each large wave 

 consists of a number of small waves of different size. By superposition 

 they cause the tops and valleys of the waves to become sharp edges. 

 The tops are bent by the wind, and are even torn and dashed into a 

 mass of spray, and the sharp edges of the valleys fall down. Thus 

 there arise numerous horizontal movements, and when the waves be- 

 gin to foam, when during a storm the sea resembles a seething cal- 

 dron, the horizontal thrusts are sufficiently numerous. Possibly the 

 eggs also glide along the surface of the waves, and the wind lashing 

 the surface of the water scatters the eggs, both those which float near 

 the tops and those which are in the valleys. It can hardly be presumed, 

 however, that such occurrences can do moie than cause the distribution 

 of the eggs, which were originally close together, over a limited area, 

 in the most favorable case, about one square mile. Direct observations 

 frequently offer technical difficulties, for when the sea is rough, bodies 

 sunk below the surface are immediately lost to sight. I let three glass 

 floats, which, like the areometers, rose but little above the surface, swim 

 in the Kiel harbor when the waves were but small, but when there was a 

 tolerably strong west wind. After they had been separated and had 

 again come together, the smallest of the thre^ was, after 10 minutes,^ 

 found about 3 meters from the two others, whicli were deeper in the 

 water, and which were about one-half meter from each other. Soon 

 after this observation I unfortunately lost sight of them. Three meters 

 in 10 minutes makes 18 meters per hour, and 6 kilometers in 14 daysj and 

 as the waves were very small when I made this experiment, and as 

 floats like those employed by me have rather an unfavorable shape, the 

 area of one square mile (German) for the open sea, as given above, does 

 not appear too large. 



It is certain that the currents which are caused by the changes of 

 the pressure of the air on the water, and which run parallel with the 

 wind, have likewise a considerable influence on the disti ibutiou of the 

 eggs. These currents cause a very considerable motion in the Baltic ; in 

 the open sea they certainly run frequently ^ mile (German) an hour, there 

 fore in 8 hours 7.5 kilometers. This causes a considerable motion and 

 upper and lower currents, which may cross each other at different points, 

 and taking into account the constantly progressing distribution caused 

 by the motion of the waves, it becomes probable that all these motions 



