1907] 
Current-Measurements. 
21 
At  West  er  Ho  Ila  a station  was  taken  on  the  Edge,  where 
the  depth  was  180  meters.  Here  too  we  have  a typical  region  of 
tidal  current,  but  the  conditions  are  much  more  complicated  than 
at  Ling  Bank.  There  appear  to  be  two  rather  sharply  defined 
tidal  regions.  At  50  and  100  meters  the  current  went  very  often 
right  across  the  direction  which  it  had  in  the  upper  layers,  some- 
times  in  fact  in  quite  an  opposite  direction,  but  always  with  the 
character  of  a tidal  stream. 
In  the  upper  20  meters  there  was,  to  judge  by  the  observations 
published  in  the  Bulletin  for  July  1906,  a layer  of  coast  water 
with  a comparatively  low  salinity.  From  about  25  meters  down  to 
75  meters  there  was  a layer  of  mixed  water,  of  salinities  between 
34  and  35  %o,  and  below  100  meters  there  was  salt  Atlantic 
water.  The  greatest  velocities  are  to  be  found  in  the  surface  layer 
Corning  Ifrom  South  and  North,  and  the  smallest  velocities  coming 
from  East  and  West.  In  the  central  layers  the  greatest  velocities 
are  to  be  found  going  in  a West-East  direction.  At  the  bottom, 
at  a depth  of  175  meters,  the  tidal  current  was  not  so  pronounced; 
and  the  water  was  carried  with  comparatively  slight  variations  tow- 
ards  the  South-East. 
On  the  Great  Fisher  Bank,  where  the  observations  cover 
a period  of  9 — 10  hours,  tliere  was  a typical  tidal  current  too, 
with  a considerable  eccentricity.  At  2 meters  the  velocities  were 
up  to  about  42  cm.  per  second  and  at  2 and  5 meters  the  velocities 
were  much  greater  with  a movement  from  SW  and  W than  with  a 
movement  from  E.,  which  clearly  points  to  a resulting  current  going 
eastwards.  A weak  southerly  wind  was  blowing,  which  probably 
had  some  influence  on  this  movement.  At  a depth  of  20  meters 
the  tidal  stream  was  apparently  more  in  evidence  than  the  resulting 
current.  It  is  very  remarkable  that  at  30  meters  the  movement 
was  the  whole  time  apparently  taking  place  in  an  almost  opposite 
direction  to  the  movement  in  the  higher  layers,  while  in  the  layer 
of  water  near  the  bottom  (60  meters)  the  stream  showed  a course 
almost  exactly  like  the  course  near  the  surface.  But  just  as  was 
the  case  at  the  Ling  Bank,  so  here  too  the  current  at  the  bottom 
seems  to  reach  its  maximum  or  minimum  an  hour  earlier  than  the 
current  at  the  surface.  The  salinity  at  the  bottom  was  over  35 
%o,  and  the  resulting  current  had  here  entirely  disappeared. 
