﻿240 
  Dr. 
  W. 
  B. 
  Carpenter 
  on 
  the 
  Nature 
  of 
  the 
  [Feb. 
  4, 
  

  

  that 
  whilst 
  the 
  whole 
  upper 
  stratum, 
  from 
  the 
  surface 
  to 
  a 
  depth 
  of 
  from 
  

   100 
  to 
  150 
  fathoms, 
  has 
  the 
  temperature 
  of 
  the 
  warm 
  flow 
  coming 
  up 
  

   from 
  the 
  S.W., 
  and 
  whilst 
  this 
  temperature 
  falls 
  so 
  gradually 
  in 
  the 
  

   " 
  warm 
  area 
  " 
  with 
  increase 
  of 
  depth 
  as 
  to 
  be 
  still 
  as 
  high 
  as 
  43° 
  Fahr. 
  

   at 
  a 
  depth 
  of 
  600 
  fathoms, 
  it 
  falls 
  so 
  suddenly 
  in 
  the 
  " 
  cold 
  area 
  " 
  be- 
  

   tween 
  150 
  aud 
  300 
  fathoms, 
  that 
  the 
  whole 
  of 
  its 
  deeper 
  stratum 
  has 
  a 
  

   temperature 
  below 
  32°, 
  the 
  bottom 
  temperature 
  descending 
  in 
  some 
  parts 
  

   to 
  29°- 
  5. 
  Now 
  on 
  this 
  " 
  cold 
  area 
  " 
  I 
  never 
  fouud 
  a 
  single 
  Globigerina, 
  

   the 
  bottom 
  consisting 
  of 
  sand 
  aud 
  gravel, 
  aud 
  the 
  Foraminifera 
  brought 
  

   up 
  from 
  it 
  being 
  almost 
  exclusively 
  those 
  which 
  form 
  arenaceous 
  tests. 
  

   The 
  " 
  warm 
  area," 
  on 
  the 
  other 
  hand, 
  is 
  covered 
  with 
  Globigerina-ooze 
  to 
  

   an 
  unknown 
  depth, 
  its 
  surf 
  ace-stratum 
  being 
  composed 
  of 
  perfect 
  shells 
  

   filled 
  with 
  sarcode, 
  whilst 
  its 
  deeper 
  layers 
  are 
  amorphous. 
  Near 
  the 
  

   junction 
  of 
  the 
  two 
  areas, 
  but 
  still 
  within 
  the 
  thermal 
  limit 
  of 
  the 
  

   " 
  warm," 
  sand 
  and 
  Globigerina-oozQ 
  are 
  miugled 
  — 
  this 
  being 
  peculiarly 
  

   noticeable 
  on 
  the 
  " 
  ffoltenia-groimd" 
  which 
  yielded 
  a 
  large 
  proportion 
  

   of 
  our 
  most 
  noteworthy 
  captures 
  in 
  this 
  locality. 
  Now 
  if 
  the 
  bottom- 
  

   deposit 
  is 
  depeudent 
  on 
  the 
  life 
  of 
  the 
  surface-stratum, 
  why 
  should 
  

   there 
  be 
  this 
  complete 
  absence 
  of 
  Globigerina-ooze 
  over 
  the 
  " 
  cold 
  area," 
  

   the 
  condition 
  of 
  the 
  surface-stratum 
  being 
  everywhere 
  the 
  same? 
  I 
  

   was 
  myself 
  formerly 
  disposed 
  to 
  attribute 
  it 
  to 
  the 
  depression 
  of 
  bottom- 
  

   temperature 
  ; 
  but 
  as 
  it 
  has 
  now 
  been 
  proved 
  by 
  the 
  ' 
  Challenger 
  ' 
  obser- 
  

   vations 
  in 
  the 
  Atlantic, 
  that 
  Globigeiina-ooze 
  prevails 
  over 
  areas 
  whose 
  

   bottom-temperature 
  is 
  but 
  little 
  above 
  32°, 
  this 
  explanation 
  can 
  no 
  longer 
  

   be 
  accepted. 
  And 
  I 
  can 
  see 
  no 
  other 
  way 
  of 
  accounting 
  for 
  it 
  than 
  by 
  

   attributing 
  it 
  to 
  the 
  drift 
  of 
  the 
  cold 
  underflow, 
  carving 
  away 
  the 
  Globi- 
  

   gerina 
  that 
  are 
  subsiding 
  through 
  it 
  towards 
  the 
  deep 
  basin 
  of 
  the 
  Atlantic, 
  

   into 
  which 
  I 
  believe 
  that 
  underflow 
  to 
  discharge 
  itself. 
  Prof. 
  Wyville 
  

   Thomson, 
  however, 
  denies 
  any 
  sensible 
  movement 
  to 
  this 
  underflow, 
  

   continuing 
  to 
  speak 
  of 
  it 
  as 
  " 
  banked 
  up 
  " 
  by 
  the 
  Grulf 
  -stream 
  *, 
  which 
  

  

  * 
  See 
  his 
  'Depths 
  of 
  the 
  Sea,' 
  p. 
  400. 
  That 
  there 
  is 
  a 
  lateral 
  pressure 
  of 
  the 
  one 
  

   flow 
  against 
  the 
  other, 
  just 
  as 
  there 
  is 
  a 
  lateral 
  pressure 
  of 
  the 
  Labrador 
  Current 
  

   against 
  the 
  G-ulf 
  -stream 
  on 
  the 
  North-American 
  coast 
  (producing 
  the 
  well-known 
  " 
  cold 
  

   wall"), 
  is 
  sufficiently 
  obvious 
  from 
  their 
  relative 
  distributions 
  on 
  the 
  bottom 
  of 
  the 
  

   channel. 
  But 
  it 
  seems 
  to 
  me 
  perfectly 
  clear 
  that 
  the 
  effect 
  of 
  this 
  pressure 
  is 
  simply 
  

   to 
  narrow 
  the 
  glacial 
  flow, 
  and 
  at 
  the 
  same 
  time 
  to 
  increase 
  its 
  velocity. 
  The 
  most 
  

   westerly 
  point 
  to 
  which 
  we 
  traced 
  it 
  was 
  near 
  the 
  edge 
  of 
  the 
  Faroe 
  Banks 
  ; 
  and 
  

   there 
  (as 
  Prof. 
  Wyville 
  Thomson 
  himself 
  pointed 
  out 
  to 
  me 
  at 
  the 
  time) 
  the 
  movement 
  

   of 
  the 
  bottom- 
  water 
  was 
  evidenced 
  by 
  the 
  rounding 
  into 
  pebbles 
  of 
  what 
  was 
  elsewhere 
  

   angidar 
  gravel. 
  But 
  it 
  is 
  even 
  more 
  conclusively 
  shown 
  by 
  a 
  comparison 
  of 
  the 
  two 
  

   serial 
  soundings 
  taken 
  in 
  the 
  " 
  cold 
  area 
  " 
  (Nos. 
  52 
  and 
  64), 
  which 
  proves 
  that 
  the 
  

   glacial 
  stratum 
  flows 
  up 
  a 
  slope 
  in 
  the 
  former 
  position 
  (just 
  as 
  the 
  cold 
  under-stratum 
  

   does 
  in 
  the 
  Florida 
  Channel), 
  which 
  it 
  could 
  not 
  do 
  unless 
  it 
  were 
  in 
  movement. 
  That 
  

   we 
  did 
  not 
  trace 
  the 
  outflow 
  of 
  this 
  cold 
  stream 
  into 
  the 
  great 
  basin 
  of 
  the 
  Atlantic, 
  

   was 
  simply, 
  as 
  I 
  believe, 
  because 
  we 
  were 
  prevented 
  from 
  ascertaining 
  the 
  bottom- 
  

   temperature 
  on 
  the 
  line 
  which 
  I 
  expected 
  that 
  flow 
  to 
  take 
  after 
  surmounting 
  the 
  

   ridge. 
  

  

  