ATLANT. DEEP SEA EXPED. 1910. VOL. i| PHYSICAL OCEANOORAPHY AND METEOROLOGY 



35 



lOOm 



200 



500 



■400 



SCO 



600 



Fig. 5. Residual variations, in metres, after elimination of the diurnal and semi-diurnal variations. 



and the vertical gradient of temperature. Comparatively 

 great oscillations may seemingly appear at various depths, 

 independently of the conditions at other levels above or 

 below. 



At Stat. 115 these variations are practically insigni- 

 ficant at 100 and 400 metres, where they are quite sub- 

 ordinate in proportion to the diurnal and semi-diurnal 

 variations. They are most marked at 200 and 300 metres. 

 The amplitudes do not differ so very much within each 



layer, but nothing can be made out with regard to definite 

 periods. 



At Slat. Sc. some few of the variations at 100, 200 

 and 300 metres are very great in comparison with the 

 others. The curves from these depths remind one of 

 curves for damped oscillations. Our curves represent the 

 variations at a fi.xed station, with the early observations 

 to the left and the late to the right, so that a wave to the 

 riyht means an undulation behind a wave more to the left. 



