2^6 MARINE BIOLOGICAL LABORATORY. 



over the various portions of the North Atlantic. A 

 simple illustration of the way in which this effect is pro- 

 duced is obtained by placing the hand with the fingers 

 together upon the table, and then forcibly moving it for- 

 ward, when it will be found almost impossible to keep 

 the fingers together ; contact with opposing currents, 

 also, tends to reduce the velocity and breaks the main 

 band up into smaller bands. 



I would call attention to the fact that this widening 

 of the stream takes place upon its eastern side, the 

 western edge being much sharper and better defined 

 than the eastern. This is probably due to the position 

 of the Labrador current between it and the coast. The 

 line of contact between these two currents is so sharp 

 that it can often be seen in the surface water from the 

 deck of a vessel. During one of the late trips of the 

 Grampus, I had a curious illustration of the fact, that 

 under proper conditions the line of contact could be 

 noticed in the dark. We were about forty miles south 

 of Nantucket, and had just completed a set of observa- 

 tions upon one of our stations. We had a strong south- 

 westerly tide, the air was so nearly quiet that we could 

 just get headway enough to hold our course, and the 

 temperature of the surface water was 6^° F. We had 

 scarcely gotten under way, when I noticed a distinct 

 noise similar to that of a tide rip, about a mile ahead of 

 us. I watched our approach to this noise with great 

 interest, as I knew there were no tide rips in this por- 

 tion of the ocean. We soon passed into the troubled 

 water, which was producing this noise. Upon taking 

 the temperature at this point I found it to be J2° F. 

 We had passed from water flowing southwest to water 



