Water Bodies and Stationary Current Conditions at Boundary Surfaces 475 



In most cases in the ocean T^ <^ Ti, so that the ''Eigen" period of such an oscillating 

 system will always be close to the inertia period. In the vortex over the "Altair" cone 

 2/ = 120 km: the mean densities of the upper and lower layer pi and po are 1-0263 

 and 1-0283 and/- 1-023 x 10"* sec-\ then for hi = 30m and h^ = 1000 m it is 

 found that T, = 17-1 h and the "Eigen" period of the system according to equation 

 (XIV. 1 5) is r = 1 6-76 h. Thus the "Eigen" period of the vortex over the "Altair" cone 

 approaches closely the period of an inertia oscillation, as was found by observation; 

 inertia oscillations are merely the free oscillations of an enclosed sea the equihbrium 

 state of which has been disturbed. They are probably set up by external causes especially 

 by meteorological conditions (hke storms and similar phenomena). In this particular 

 case a storm occurring just before the anchoring of the "Altair" seems to be the cause 

 for the pulsation of the otherwise stationary vortex above the "Altair" submarine 

 volcano. 



