1907J 
Current-Measurements. 
7 
All  the  ohservations  in  the  ta  bles  below  have  been  worked 
out  in  full,  so  as  to  give  the  reader  a clear  idea  of  all  the  details. 
Mean  European  time  has  been  used  througiiout.  We  have  given 
the  time  when  the  ohservations  were  commenced,  and  the  time 
during  which  the  apparatus  was  working.  Fnrther  the  number  of 
i’evolutions  of  the  propeller  are  recorded.  The  velocities  have  been 
calculated  from  the  formula  given  above;  it  must  be  nnderstood  that 
velocities  under  3 cm./sec.  are  ahvays  open  to  doubt.  The  mean 
direction  has  been  corrected  for  magnetic  deviations,  though' single 
directions  have  not.  In  the  case  of  each  station  we  have  shown 
time  and  place  as  well  as  magnetic  deviation  and  depth:  while 
the  wiud  conditions  will  also  be  fonnd  stated,  together  with  the 
passage  of  the  moon  (upper  passage  in  italics)  and  tlie  age  of  the 
moon.  The  salinities  and  the  temperatures  are  also  recorded. 
The  ohservations  were  taken  during  two  cruises  of  the  ”Michael 
Sars”.  On  the  first  of  them,  during  the  eaiiier  part  of  July,  we 
were  working  in  the  Sondmore  Fiords,  and  on  the  Banks  and  Edge 
off  Aalesund.  During  this  cruise  the  measurements  were  made  by 
my  friend  Dr.  D.  Damas  and  myself.  The  next  cruise  was  to  the 
Skagerack  and  North  Sea  at  the  end  of  July  and  the  beginning  of 
August.  On  this  occasion  the  ohservations  were  made  by  Dr. 
Damas  assisted  by  Engineer  Coeneliussen.  Unfortunately  all  the 
water-samples  from  this  last  cruise  were  lost  through  an  accident  on 
board,  so  that  in  the  tables  we  have  only  shown  the  station  obser- 
vations  that  in  time  and  place  most  closely  coincide  with  our  sta- 
tions  for  current-measurements  as  per  the  International  Bulletin. 
The  ohservations  were  first  recorded  on  millimetcr-paper  with 
rectangular  co-ordinates;  the  time  along  the  abscissa  axis  and  the 
velocities  or  directions  shown  as  ordinates.  It  is  from  gr  ap  hi  cal 
represeutations  like  these  that  one  gets  the  best  impression  of  the 
variations  from  hour  to  hour.  An  example  may  be  fonnd  in  figures 
5,  6,  10  and  H.  On  such  represeutations  of  the  directions  we  see  the 
constaut  currents  represented  by  horizontal  lines.  Tidal  currents, 
v-hich  in  open  waters  are  characterised  by  constaut  change  of  di- 
rection round  all  the  points  of  the  compass,  are  represented  in  the 
rectangular  co-ordinate  system  by  means  of  lines  that  lie  across  the 
paper  (see  figure  6).  On  figures  10  and  11  we  see  typical  repre- 
sentations  of  currents  with  a single  direction  as  wel  as  tidal  currents 
