or other large-scale motions. Variations on the vertical motion are 

 also small enough to pose severe measuring problems. Pressure fluctu- 

 ations are almost numerically equal to the square of the velocity and 



_2 

 so are of the order of 1 dyne cm . These pressure changes would be 



difficult to detect at the expected frequencies of 0.004 sec or lower. 



In most cases the detection equipment could not be tied to a 

 ship. Free floating devices, such as Swallow's neutrally buoyant 

 cylinder, offer exceptional opportunities for quiet measurements and 

 invaluable data could be collected if telemetering devices were developed 

 to send up information directly from such cylinders. 



A promising method of studying the turbulent motion is to follow 

 the motion of two or more neutral cylinders at depth. Measurements of 

 changes in their separation with time should give detailed information 

 on the velocity structure of the water. 



-20- 



