VERTICAL A\D HORIZONTAL MOVEMENTS IN THE OCEAN 617 



'Resident Wdter A 



^Resident IVjter B 



Jntrusit^e 9^te 



:Resideni IVater D 



Fig. 10. A solid diagram to illustrate the possible fate of boluses descending 

 the eastern face of the mid-Atlantic ridge or the continental slope of North America. 

 The boluses first come to rest on the discontinuity platform between two resident 

 water masses B and C, each in adiabatically neutral equilibrium, and then spread 

 out between the resident water masses as thin lamina having lenticular structure. 



Neutral Buoyancy Floats 



These depend on the relative comprcssihiHty of the float and of 

 water (Swallow, 1955). Even in water in neutral adiabatic equi- 

 librium, the density in situ increases with depth so that some floats 

 may float within such a water mass. Nevertheless the laminated 

 structure of the deep water may result in many floats coming to 

 rest on the discontinuity platforms. These platforms are likely to 

 have the properties of glide planes with large variations in direc- 

 tion and strength of current within a vertical range of a few meters. 

 Consequently, the use of free floating devices for measuring very 

 deep currents may suffer from restrictions imposed, if the thesis is 

 true, by the very nature of the deep sea. 



Furthermore, at these discontinuities, neutral buoyancy devices 

 may, perhaps, bounce about for a while with little hysteresis loss. 



