Skip to main content

Full text of "The physical geography of the sea"

See other formats 


K^r 


U^: 


■WA 


WMimt 


irishi 


Marine  Biological  Laboratory  Ubrary 

Woods  Hole,  /Massachusetts 


Gift  of  Dean  Bumpus  -   1976 


; 


/' 


/ 


// 


THE 


/»   - 


PHYSICAL  GEOGRAPHY 


1-1 

OP 


THE    SEA. 


BY   M.  P.  MAURY,  LLD,  U.S.N., 

STJPEEINTENDENT  OP  THE  NATIONAL  OBSERVATOBT. 


AN     ENTIRELY     NEW     EDITION,     WITH     ADDENDA. 


NEW    YOEK: 

HARPER    &    BROTHERS,    PUBLISHERS. 

LONDON: 

SAMPSON    LOW,    SON    &    CO. 

18  5  8. 


Entered,  according  to  Act  of  Congress,  in  the  year  one  thousand  eight 
hundred  and  fifty-six,  by 

Harper  &  Brothers, 

in  the  Clerk's  Ofiice  of  the  District  Court  of  the  Southern  District  of 

New  York. 


AS 


A  TOKEN  OF  FRIENDSHIP,  AND  A  TRIBUTE  TO  WORTH, 

GEORGE    MANNING, 

OF  NEW  YORK. 
Washington  Observatoby,  April,  1856. 


INTRODUCTION^  TO  THE  FIRST  EDITION.-1855. 


The  primaiy  object  of  "The  Wind  and  Current  Charts,"  out 
of  which  has  grown  this  Treatise  on  the  Physical  Geography  of 
the  Sea,  was  to  collect  the  experience  of  every  navigator  as  to  the 
winds  and  currents  of  the  ocean,  to  discuss  his  observations  upon 
them,  and  then  to  present  the  world  with  the  results  on  charts  for 
the  improvement  of  commerce  and  navigation. 

By  putting  down  on  a  cliart  the  tracks  of  many  vessels  on  the 
same  voyage,  but  at  different  times,  in  different  years,  and  during 
all  seasons,  and  by  projecting  along  each  track  the  winds  and  cur- 
rents daily  encountered,  it  was  plain  that  navigators  hereafter,  by 
consulting  this  chart,  would  have  for  their  guide  the  results  of  the 
combined  experience  of  all  whose  tracks  were  thus  pointed  out. 

Perhaps  it  might  be  the  first  voyage  of  a  young  navigator  to 
the  given  port,  when  his  own  personal  experience  of  the  winds  to 
be  expected,  the  currents  to  be  encountered  by  the  way,  would  it- 
self be  blank.  If  so,  there  would  be  the  wind  and  current  chart. 
It  would  spread  out  before  him  the  tracks  of  a  thousand  vessels 
that  had  preceded  him  on  the  same  voyage,  wherever  it  might  be, 
and  that,  too,  at  the  same  season  of  the  year.  Such  a  chart,  it 
was  held,  would  show  him  not  only  the  tracks  of  the  vessels,  but 
the  experience  also  of  each  master  as  to  the  winds  and  currents 
by  the  way,  the  temperature  of  the  ocean,  and  the  variation  of  the 
needle.  All  this  could  be  taken  in  at  a  glance,  and  thus  the  young 
mariner,  instead  of  groping  his  way  along  until  the  lights  of  expe- 
rience should  come  to  him  by  the  slow  teachings  of  the  dearest 
of  all  schools,  would  here  find,  at  once,  that  he  had  already  the 
experience  of  a  thousand  navigators  to  guide  him  on  his  voyage. 
He  might,  therefore,  set  out  upon  his  first  voyage  with  as  much 
confidence  in  his  knowledge  as  to  the  winds  and  currents  he  might 
expect  to  meet  with,  as  though  he  himself  had  already  been  that 
way  a  thousand  times  before. 

Such  a  chart  could  not  fail  to  commend  itself  to  intelligent 


viii  INTRODUCTION. 

ship-masters,  and  such  a  chart  was  constructed  for  them.  They 
took  it  to  sea,  they  tried  it,  and  to  their  surprise  and  delight  they 
found  that,  with  the  knowledge  it  afforded,  the  remote  corners  of 
the  earth  were  "brought  closer  together,  in  some  instances  by  many 
days'  sail.  The  passage  hence  to  the  equator  alone  was  shorten- 
ed ten  days.  Before  the  commencement  of  this  undertaking,  the 
average  passage  to  California  was  183  days  ;  but  with  these  charts 
for  their  guide,  navigators  have  reduced  that  average,  and  brought 
it  down  to  135  days. 

Between  England  and  Australia,  the  average  time  going,  with- 
out these  charts,  is  ascertained  to  be  124  days,  and  coming,  about 
the  same ;  making  the  round  voyage  one  of  about  250  days  on 
the  average. 

These  charts,  and  the  system  of  research  to  which  they  have 
given  rise,  bid  fair  to  bring  that  colony  and  the  mother  country 
nearer  by  many  days,  reducing,  in  no  small  measure,  the  average 
duration  of  the  round  voyage.* 

At  the  meetino;  of  the  British  Association  of  1853,  it  was  stated 
by  a  distinguished  member — and  the  statement  was  again  repeat- 
ed at  its  meeting  in  1854 — that  in  Bombay,  whence  he  came,  it 
was  estimated  that  this  system  of  research,  if  extended  to  the  In- 
dian Ocean,  and  embodied  in  a  set  of  charts  for  that  sea,  such  as 
I  have  been  describing,  would  produce  an  annual  saving  to  Brit- 
ish commerce,  in  those  waters  alone,  of  one  or  two  millions  of  dol- 
lars ;t  and  in  all  seas,  often  millions.  { 

*  The  outward  passage,  it  has  since  heen  ascertained,  has  been  reduced  to  97  days 
on  the  average,  and  the  homeward  passage  has  been  made  in  63. 

t  See  Inaugural  Address  of  the  Earl  of  Harrowby,  President  of  the  British  Associ- 
ation at  its  twenty- fourth  meeting.     Liverpool,  1854. 

t  •  •  •  "  Now  let  us  make  a  calculation  of  the  annual  saving  to  the  commerce  of  the 
United  States  effected  by  those  charts  and  sailing  directions.  According  to  Mr.  Maury, 
the  average  freight  from  the  United  States  to  Rio  Janeiro  is  17.7  cts.  per  ton  per  day ; 
to  Australia,  20  cts. ;  to  California,  also,  about  20  cts.  The  mean  of  this  is  a  Uttle 
over  19  cents  per  ton  per  day  ;  but  to  be  within  the  mark,  we  will  take  it  at  15,  and 
include  all  the  ports  of  South  America,  China,  and  the  East  Indies. 

"  The  sailing  directions  have  shortened  the  passages  to  Cahfornia  30  days,  to  Aus- 
traUa  20,  to  Rio  Janeiro  10.  The  mean  of  this  is  20,  but  we  will  take  it  at  15,  and 
also  include  the  above-named  ports  of  South  America,  China,  and  the  East  Indies. 

"We  estimate  the  tonnage  of  the  United  States  engaged  in  trade  with  these  places 
at  1,000,000  tons  per  annum. 


INTRODUCTION.  j^ 

A  system  of  pliilosophical  research,  which  is  so  rich  with  fruits 
and  abundant  with  promise,  could  not  fail  to  attract  the  attention 
and  commend  itself  to  the  consideration  of  the  seafaring  commu- 
nity of  the  whole  civilized  world.  It  was  founded  on  observation ; 
it  was  the  result  of  the  experience  of  many  observant  men,  now 
brought  together  for  the  first  time  and  patiently  discussed.  The 
results  tended  to  increase  human  knowledge  with  regard  to  the  sea 
and  its  wonders,  and  therefore  the  system  of  research  could  not  be 
wanting  in  attractions  to  right-minded  men. 

The  results  of  the  first  chart,  however,  though  meagre  and  un- 
satisfactory, were  brought  to  the  notice  of  navigators ;  their  at- 
tention was  called  to  the  blank  spaces,  and  the  importance  of 
more  and  better  observations  than  the  old  sea-logs  generally  con- 
tained was  urged  uj^on  them. 

They  were  told  that  if  each  one  would  agree  to  co-operate  in  a 
general  plan  of  observations  at  sea,  and  would  send  regularly,  at 
the  end  of  every  cruise,  an  abstract  log  of  their  voyage  to  the 
National  Observatory  at  Washington,  he  should,  for  so  doing,  be 
furnished,  free  of  cost,  with  a  copy  of  the  charts  and  sailing  di- 
rections that  might  be  founded  upon  those  observations. 

The  quick,  practical  mind  of  the  American  ship-master  took 
hold  of  the  proposition  at  once.  To  him  the  field  was  inviting, 
for  he  saw  in  it  the  promise  of  a  rich  harvest  and  of  many  useful 
results. 

So,  in  a  little  while,  there  were  more  than  a  thousand  naviga- 
tors engaged  day  and  night,  and  in  all  parts  of  the  ocean,  in  mak- 
ing and  recording  observations  according  to  a  uniform  plan,  and 
in  furthering  this  attempt  to  increase  our  knowledge  as  to  the 
winds  and  currents  of  the  sea,  and  other  phenomena  that  relate  to 
its  safe  navigation  and  physical  geography. 

"  With  these  data,  we  see  that  there  has  been  effected  a  saving  for  each  one  of  these 
tons  of  15  cents  per  day  for  a  period  of  15  days,  which  will  give  an  aggregate  of 
S2, 250, 000  saved  per  annum.  This  is  on  the  outward  voyage  alone,  and  the  tonnage 
trading  with  all  other  parts  of  the  world  is  also  left  out  of  the  calculation.  Take  these 
into  consideration,  and  also  the  fact  that  there  is  a  vast  amount  of  foreign  tonnage 
trading  between  these  places  and  the  United  States,  and  it  will  be  seen  that  the  an- 
nual sum  saved  will  swell  to  an  enormous  amount." — Extract  from  Hunfs  Merchant's 
Magazine,  May,  1854. 


X  INTRODUCTION. 

To  enlist  the  service  of  such  a  large  corps  of  ohservers,  and  to 
have  the  attention  of  so  many  clever  and  observant  men  directed 
to  the  same  subject,  was  a  great  point  gained :  it  was  a  giant 
stride  in  the  advancement  of  knowledge,  and  a  great  step  toward 
its  spread  upon  the  waters. 

Important  results  soon  followed,  and  great  discoveries  were 
made.  These  attracted  the  attention  of  the  commercial  world, 
and  did  not  escape  the  notice  of  philosophers  every  where. 

The  field  was  immense,  the  harvest  was  plenteous,  and  there 
was  both  need  and  room  for  more  laborers.  Whatever  the  reap- 
ers should  gather,  or  the  merest  gleaner  collect,  was  to  inure  to  the 
benefit  of  commerce  and  navigation — the  increase  of  knowledge — 
the  good  of  all. 

Therefore,  all  who  use  the  sea  were  equally  interested  in  the 
undertaking.  The  government  of  the  United  States,  so  consider- 
ing the  matter,  proposed  a  uniform  system  of  observations  at  sea, 
and  invited  all  the  maritime  states  of  Christendom  to  a  conference 
upon  the  subject. 

This  conference,  consisting  of  representatives  from  France,  En- 
gland and  Russia,  from  Sweden  and  Norway,  Holland,  Denmark, 
Belgium,  Portugal,  and  the  United  States,  met  in  Brussels,  August 
23, 1853,  and  recommended  a  plan  of  observations  which  should  be 
followed  on  board  the  vessels  of  all  friendly  nations,  and  especial- 
ly of  those  there  present  in  the  persons  of  their  representatives. 

Prussia,  Spain,  Sardinia,  the  Holy  See,  the  free  city  of  Ham- 
burg, the  republics  of  Bremen  and  Chili,  and  the  empires  of  Aus- 
tria and  Brazil,  have  since  off*ered  their  co-operation  also  in  the 
same  plan. 

Thus  the  sea  has  been  brought  regularly  within  the  domains  of 
philosophical  research,  and  crowded  with  observers. 

In  peace  and  in  war  these  observations  are  to  be  carried  on ; 
and,  in  case  any  of  the  vessels  on  board  of  which  they  are  con- 
ducted may  be  captured,  the  abstract  log — as  the  journal  which 
contains  these  observations  is  called — is  to  be  held  sacred. 

Baron  Humboldt  is  of  opinion  that  the  results  already  obtained 
from  this  system  of  research  are  sufiicient  to  give  rise  to  a  new  de- 
partment of  science,  which  he  has  called  the  Physical  Geogea- 


INTRODUCTION.  ^j 

FHY  OF  THE  Sea.  If  SO  much  have  already  been  accomplished 
by  one  nation,  what  may  we  not  expect  in  the  course  of  a  few 
years  from  the  joint  co-operation  of  so  many  ? 

Rarely  before  has  there  been  such  a  sublime  spectacle  presented 
to  the  scientific  world :  all  nations  agreeing  to  unite  and  co-op- 
erate in  carrying  out  one  system  of  philosophical  research  with 
regard  to  the  sea.  Though  they  may  be  enemies  in  all  else,  here 
they  are  to  be  friends.  Every  ship  that  navigates  the  high  seas 
with  these  charts  and  blank  abstract  logs  on  board  may  henceforth 
be  regarded  as  a  floating  observatory,  a  temple  of  science.  The 
instruments  used  by  every  co-operating  vessel  are  to  be  compared 
with  standards  that  are  common  to  all ;  so  that  an  observation 
that  is  made  any  where  and  in  any  ship,  may  be  referred  to  and 
compared  with  all  similar  observations  by  all  other  ships  in  all 
parts  of  the  world. 

But  these  meteorological  observations  which  this  extensive  and 
admirable  system  includes  will  relate  only  to  the  sea.  This  is 
not  enough.  The  plan  should  include  the  land  also,  and  be  uni- 
versal. Other  great  interests  of  society  are  to  be  benefited  by 
such  extension  no  less  than  commerce  and  navigation  have  been. 
A  series  of  systematic  observations,  directed  over  large  districts  of 
country,  nay,  over  continents,  to  the  improvement  of  agricultural 
and  sanitary  meteorology,  would,  I  have  no  doubt,  tend  to  a  devel- 
opment of  many  interesting,  important,  and  valuable  results. 

The  agricultural  societies  of  many  states  of  the  Union  have  ad- 
dressed memorials  to  the  American  Congress,  asking  for  such  ex- 
tension ;  and  it  is  hoped  that  that  enlightened  body  will  not  fail 
favorably  to  respond. 

This  plan  contemplates  the  co-operation  of  all  the  states  of 
Christendom,  at  least  so  far  as  the  form,  method,  subjects  of  ob- 
servations, time  of  making  them,  and  the  interchange  of  results 
are  concerned.  I  hope  that  my  fellow-citizens  will  not  fail  to  sec- 
ond and  co-operate  in  such  a  humane,  wise,  and  noble  scheme. 
The  Secretary  of  the  Navy,  taking  the  enlarged  and  enlightened 
views  which  do  honor  to  great  statesmen,  has  officially  recom- 
mended the  adoption  of  such  a  system,  and  the  President  has 
asked  the  favorable  consideration  thereof  by  Congress.     These  re- 


xii  INTRODUCTION. 

searches  for  the  land  look  not  only  to  the  advancement  of  the  great 
interests  of  sanitary  and  agricultural  meteorology,  but  they  involve 
also  a  study  of  the  laws  which  regulate  the  atmosphere,  and  a 
careful  investigation  of  all  its  phenomena. 

Another  beautiful  feature  in  this  system  is,  that  it  costs  noth- 
ing additional.  The  instruments  that  these  observations  at  sea 
call  for  are  such  as  are  already  in  use  on  board  of  every  well-con- 
ditioned ship,  and  the  observations  that  are  required  are  precisely 
those  which  are  necessary  for  her  safe  and  proper  navigation. 

As  great  as  is  the  value  attached  to  what  has  been  accomplished 
by  these  researches  in  the  way  of  shortening  passages  and  lessen- 
ing the  dangers  of  the  sea,  a  good  of  higher  value  is,  in  the  opin- 
ion of  many  seamen,  yet  to  come  out  of  the  moral,  the  educational 
influence  which  they  are  calculated  to  exert  upon  the  seafaring 
community  of  the  world.  A  very  clever  English  shipmaster, 
speaking  recently  of  the  advantages  of  educational  influences 
amono;  those  who  intend  to  follow  the  sea,  remarks : 

"To  the  cultivated  lad  there  is  a  new  world  spread  out  when 
he  enters  on  his  first  voyage.  As  his  education  has  fitted,  so  will 
he  perceive,  year  by  year,  that  his  profession  makes  him  acquaint- 
ed with  things  new  and  instructive.  His  intelligence  will  enable 
him  to  appreciate  the  contrasts  of  each  country  in  its  general  as- 
pect, manners,  and  productions,  and  in  modes  of  navigation  adapt- 
ed to  the  character  of  coast,  climate,  and  rivers.  He  will  dwell 
with  interest  on  the  phases  of  the  ocean,  the  storm,  the  calm,  and 
the  breeze,  and  will  look  for  traces  of  the  laws  which  regulate 
them.  All  this  will  induce  a  serious  earnestness  in  his  work,  and 
teach  him  to  view  lightly  those  irksome  and  often  ofiensive  duties 
incident  to  the  beginner,"* 

And  that  these  researches  do  have  such  an  effect  many  noble- 
hearted  mariners  have  testified.  Captain  Phinney,  of  the  Ameri- 
can ship  Gertrude,  writing  from  Callao,  January,  1855,  thus  ex- 
presses himself: 

"  Having  to  proceed  from  this  to  the  Chincha  Islands  and  re- 

*  "  The  Log  of  a  Merchant  Officer  ;  viewed  with  reference  to  the  Education  of 
young  Olficers  and  the  Youth  of  the  Merchant  Service.  By  Robert  Methren,  com- 
mander in  the  Peninsular  and  Oriental  Company,  and  author  of  the  '  Narrative  of  the 
Blenheim  Hurricane  of  1851.'"  London:  John  Weale,  59  High  Holborn ;  Smith, 
Elder  &  Co.,  Cornhill ;  Ackerman  &  Co.,  Strand.     1854. 


INTRODUCTION.  -^m 

main  three  months,  I  avail  myself  of  the  present  opportunity  to 
forward  to  you  abstracts  of  my  two  passages  over  your  southern 
routes,  although  not  required  to  do  so  until  my  own  return  to  the 
United  States  next  summer ;  knowing  that  you  are  less  amply 
supplied  with  abstracts  of  voyages  over  these  regions  than  of  many 
other  parts  of  the  ocean,  and,  such  as  it  is,  I  am  happy  to  con- 
tribute my  mite  toward  furnishing  you  with  material  to  work  out 
still  farther  toward  perfection  your  great  and  glorious  task,  not 
only  of  pointing  out  the  most  speedy  routes  for  ships  to  follow 
over  the  ocean,  but  also  of  teaching  us  sailors  to  look  about  us, 
and  see  by  what  w^onderful  manifestations  of  the  wisdom  and  good- 
ness of  the  great  God  we  are  continually  surrounded. 

"  For  myself,  I  am  free  to  confess  that  for  many  years  I  com- 
manded a  ship,  and,  although  never  insensible  to  the  beauties  of 
nature  upon  the  sea  or  land,  I  yet  feel  that,  until  I  took  up  your 
work,  I  had  been  traversing  the  ocean  blindfolded.  I  did  not 
think ;  I  did  not  know  the  amazing  and  beautiful  combination  of 
all  the  works  of  Him  whom  you  so  beautifully  term  '  the  Great 
First  Thought.' 

"I  feel  that,  aside  from  any  pecuniary  profit  to  myself  from 
your  labors,  you  have  done  me  good  as  a  man.  You  have  taught 
me  to  look  above,  around,  and  beneath  me,  and  recognize  God's 
hand  in  every  element  by  which  I  am  sun'ounded.  I  am  grateful 
for  this  personal  benefit.  Your  remarks  on  this  subject,  so  fre- 
quently made  in  your  work,  cause  in  me  feelings  of  the  greatest 
admiration,  although  my  capacity  to  comprehend  your  beautiful 
theory  is  very  limited. 

"The  man  of  such  sentiments  as  you  express  will  not  be  dis- 
pleased with,  or,  at  least,  will  know  how  to  excuse,  so  much  of 
what  (in  a  letter  of  this  kind)  might  be  termed  irrelevant  matter. 
I  have  therefore  spoken  as  I  feel,  and  with  sentiments  of  the 
gTeatest  respect."  Sentiments  like  these  can  not  fail  to  meet  with 
a  hearty  response  from  all  good  men,  whether  ashore  or  afloat. 

Never  before  has  such  a  corps  of  observers  been  enlisted  in  the 
cause  of  any  department  of  physical  science  as  is  that  which  is 
now  about  to  be  engaged  in  advancing  our  knowledge  of  the  Phys- 
ical Geography  of  the  Sea,  and  never  before  have  men  felt  such  an 
interest  with  regard  to  this  knowledge. 


xiy  INTRODUCTION. 

Under  this  term  will  be  included  a  philosophical  account  of  the 
winds  and  currents  of  the  sea ;  of  the  circulation  of  the  atmosphere 
and  ocean  ;  of  the  temperature  and  depth  of  the  sea ;  of  the  won- 
ders that  he  hidden  in  its  depths  ;  and  of  the  phenomena  that  dis- 
play themselves  at  its  surface.  In  short,  I  shall  treat  of  the  econ- 
omy of  the  sea  and  its  adaptations — of  its  salts,  its  waters,  its  cli- 
mates, and  its  inhabitants,  and  of  whatever  there  may  be  of  gen- 
eral interest  in  its  commercial  uses  or  industrial  pursuits,  for  all 
such  things  pertain  to  its  Physical  Geography. 

The  object  of  this  little  book,  moreover,  is  to  show  the  present 
state,  and,  from  time  to  time,  the  progress  of  this  new  and  beautiful 
system  of  research,  as  well  as  of  this  interesting  department  of  sci- 
ence ;  and  the  aim  of  the  author  is  to  present  the  gleanings  from 
this  new  field  in  a  manner  that  may  be  interesting  and  instructive 
to  all,  whether  old  or  young,  ashore  or  afloat,  who  desire  a  closer 
look  into  "  the  wonders  of  the  great  deep,"  or  a  better  knowledge 
as  to  its  winds,  its  adaptations,  or  its  Physical  Geography.* 

*  There  is  an  old  and  very  rare  book  which  treats  upon  some  of  the  subjects  to  which 
this  little  work  relates.  It  is  by  Count  L.  F.  Marsigli,  an  Italian,  and  is  called 
Natural  Description  of  the  Seas.  The  copy  to  which  I  refer  was  translated  into 
Dutch  by  Boerhaave  in  1786. 

The  French  count  made  his  observations  along  the  coast  of  Provence  and  Langue- 
doc.  The  description  only  relates  to  that  part  of  the  Mediterranean.  The  book  is  di- 
vided into  four  chapters  :  the  first,  on  the  bottom  and  shape  of  the  sea ;  the  second,  of 
sea  water  ;  the  tliird,  on  the  movements  of  sea  water  ;  and  the  fourth,  of  sea  plants. 

He  divides  sea  water  into  surface  and  deep-sea  water  ;  because,  when  he  makes  salt 
from  surface  water  (not  more  than  half  a  foot  below  the  upper  strata),  this  salt  will 
give  a  red  color  to  blue  paper ;  whereas  the  salt  from  deep-sea  water  will  not  alter  the 
colors  at  all.  The  blue  paper  can  only  change  its  color  by  the  action  of  an  acid.  The 
reason  why  this  acid  (iodine'?)  is  found  in  surface  and  not  in  deep-sea  water  is,  it  is 
derived  from  the  air  ;  but  he  supposes  that  the  saltpetre  that  is  found  in  sea  water,  by 
the  action  of  the  sun's  rays  and  the  motion  of  the  waves,  is  deprived  of  its  coarse  parts, 
and,  by  evaporation,  embodied  in  the  air,  to  be  conveyed  to  beasts  or  plants  for  their 
existence,  or  deposited  upon  the  earth's  crust,  as  it  occurs  on  the  plains  of  Hungary, 
where  the  earth  absorbs  so  much  of  this  saltpetre  vapor. 

Donati,  also,  was  a  valuable  laborer  in  this  field.  His  inquiries  enabled  Mr.  Trem- 
bley^  to  conclude  that  there  are,  "  at  the  bottom  of  the  water,  mountains,  plains,  val- 
leys, and  caverns,  just  as  upon  the  land." 

But  by  far  the  most  interesting  and  valuable  book  touching  the  physical  geography 
of  the  Mediterranean  is  Admiral  Smyth's  last  work,  entitled  "  The  Mediterranean;  a 
Memoir,  Physical,  Historical,  and  Nautical.  By  Rear-admiral  William  Henry 
Smyth,  K.S.F.,  D.C.L.,"  &c.     London  :  John  W.  Parker  and  Son.     1854. 


1  Philosophical  Transactions. 


INTRODUCTION  TO  THE  SIXTH  EDITION. 


The  department  of  the  Physical  Geography  of  the  Sea  is  a  new 
field  of  research ;  there  is  great  activity  in  it,  and  it  is  the  aim  of 
the  author  of  this  work  to  keep  its  readers  posted  up  with  the  im- 
provements, the  developments,  and  the  contributions  that  are  made 
in  this  interesting  field  from  time  to  time. 

The  present  edition  contains  much  that  is  new ;  for  the  fifth 
edition  has  been  most  carefully  revised,  much  of  it  has  been  re- 
cast, and  some  parts  omitted. 

The  desire  is,  that  this  work  shall  keep  pace  with  the  progress 
of  research.  As  it  may  be  supposed,  facts  are  sometimes  misin- 
terpreted or  not  understood  when  first  developed.  Whenever  sub- 
sequent research  shows  such  to  have  been  the  case,  I  have  not 
hesitated  to  tear  down  whatever  of  conjecture  or  theory  may  have 
been  built  on  unstable  foundations,  and  to  reconstruct  according 
to  the  best  lights. 

It  is  proper  to  say  that,  in  accounting  for  the  various  phenome- 
na that  present  themselves,  I  am  wedded  to  no  theories,  and  do  not 
advocate  the  doctrines  of  any  particular  school.  Truth  is  my  ob- 
ject. Therefore,  when  the  explanation  which  I  may  have  at  any 
time  offered  touching  any  facts  fails  to  satisfy  farther  developments, 
it  is  given  up  the  moment  one  is  suggested  which  will  account  for 
the  new,  and  equally  as  well  for  the  old  system  of  facts.  In  every 
instance  that  theory  is  preferred  which  is  reconcilable  with  the 
greatest  number  of  known  facts.  The  chapter  of  the  Gulf  Stream 
has  been  enriched  with  the  results  of  recent  investigation,  and  the 
theory  of  it  farther  developed.  So  also  that  on  the  Salts  of  the 
Sea ;  the  Open  Sea  in  the  Arctic  Ocean  ;  the  Basin  of  the  Atlan- 
tic, and  several  others,  but  these  especially  have  been  greatly  im- 
proved. 


xvi  INTRODUCTION  TO  THE  SIXTH  EDITION. 

A  separate  chapter  is  now  devoted  to  the  Land  and  Sea  Breezes, 
and  extensive  contributions  have  been  made  to  that  on  Monsoons, 
Trade  Winds,  and  Cyclones.  Lieutenant  Jansen,  of  the  Dutch 
Navy,  has  helped  me  to  enrich  these  with  his  fine  thoughts.  The 
reader  will,  I  am  sure,  feel,  as"  I  do,  deeply  indebted  to  him  for  so 
much  instructive  matter,  set  forth  in  his  very  delightful  and  pleas- 
ing manner. 

National  Observatory,  Washington,  April,  1856. 

Since  the  above  date,  explorations  have  been  made  in  this  in- 
teresting department  of  science,  and  new  veins  of  precious  ore  have 
been  hit  upon.  We  have  not  yet  gone  deep  enough  into  them  to 
justify  a  final  report ;  a  preliminary  one  is  given  in  the  Addenda. 

In  1849  Congress  passed  an  act  requiring  the  Secretary  of  the 
Navy  to  employ  three  small  vessels  in  assisting  me  to  perfect  my 
discoveries.  A  few  weeks  ago.  Lieutenant  Berryman  put  to  sea 
in  the  "  Arctic"  on  this  duty.  His  attention  was  especially  direct- 
ed to  deep-sea  soundings  along  the  great  telegraphic  plateau 
stretching  from  Newfoundland  to  Ireland.  The  results,  so  far, 
are  of  the  highest  interest.  Among  them  is  the  discovery  of  a  line 
of  volcanic  cinders  along  a  line  a  thousand  miles  in  length,  and 
reaching  entirely  across  the  Gulf  Stream  where  the  submarine 
telegraph  is  to  cross  it. 

There  is  also  among  the  Addenda  Lieutenant  Jansen's  exper- 
iments upon  Ozone,  which  cast  unexpected  light  upon  the  circu- 
lation of  the  atmosphere. 

Matter  of  more  general  or  higher  scientific  importance  than  that 
contained  in  these  Addenda  is  seldom  gathered  from  any  fields  of 
research. 

December,  1856. 


CONTENTS, 


CHAPTER  I. 

THE    GULF    STREAM. 

Its  Color,  ^  2. — Theories,  5. — Capt.  Livingston's,  6. — Dr.  Franklin's,  7. — Admiral 
Smyth  and  Mediterranean  Currents,  8. — Trade  Winds  not  the  Cause  of  the  Gulf 
Stream,  9. — Drift  of  Bottles,  12. — Sargasso  Sea,  13. — Hypothetical  System  of  Cur- 
rents, 19. — Galvanic  Properties  of  the  Gulf  Stream,  26. — Saltness  of  ditto,  29. — 
Effects  produced  upon  Currents  by  Evaporation,  32. — Gulf  Stream  Roof-shaped, 
39. — Effects  of  Diurnal  Rotation  upon  Running  Water,  42. — Course  of  the  Gulf 
Stream  not  altered  by  Nantucket  Shoals,  52. — The  Trough  in  the  Sea  through 
which  the  Gulf  Stream  flows  has  a  Vibratory  Motion,  54. — Streaks  of  Warm  and 
Cold  Water  in  the  Gulf  Stream,  57. — Runs  up  Hill,  59. — A  Cushion  of  Cold  Wa- 
ter, 60 Page  25 

CHAPTER  H. 

INFLUENCE    OP    THE    GULF    STREAM    UPON    CLIMATES. 

How  the  Climate  of  England  is  regulated  by  it,  §  61. — Isothermal  Lines  of  the  At- 
lantic, 65. — Deep-sea  Temperatures  under  the  Gulf  Stream,  68. — Currents  indi- 
cated by  the  Fish,  70. — Sea-nettles,  73. — Climates  of  the  Sea,  75. — Offices  of  the 
Sea,  76. — Influence  of  the  Gulf  Stream  upon  the  Meteorology  of  the  Ocean,  78. — 
Furious  Storms,  80. — Dampness  of  the  English  Climate  due  t'le  Gulf  Stream,  83.' 
— Its  Influence  upon  Storms,  85. — Wreck  of  the  Steamer  San  Francisco,  88. — 
Influence  of  the  Gulf  Stream  upon  Commerce  and  Navigation,  96. — Used  for  find- 
ing Longitude,  103. — Commerce  in  1769,  106 50 

CHAPTER  III. 

THE     ATMOSPHERE. 

Its  Connection  with  the  Physical  Geography  of  the  Sea,  ^  113. — Description,  114. — 
Order  in  Sea  and  Air,  119. — The  Language  and  Eloquence  of  Nature,  120. — The 
Trade-winds,  122. — Plate  I.,  Circulation  of  the  Atmosphere,  123. — An  Illustration, 
126. — Theory,  128. — Where  and  why  the  Barometer  stands  highest,  133. — The 
Pleiades,  142. — Trade-wind  Clouds,  146. — Forces  concerned,  149. — Heat  and  Cold, 
150. — How  the  Winds  turn  about  the  Poles,  155. — Offices  of  the  Atmosphere,  159. 
— Mechanical  Power  of,  167. — Whence  come  the  Rains  for  the  Northern  Hemi- 
sphere'? 169. — Quantity  of  Rain  in  each  Hemisphere,  175. — The  saltest  Portion  of 
the  Sea,  179. — The  Northeast  Trade-winds  take  up  Vapors  for  the  Southern  Hem- 
isphere, 181. — Rainy  Seasons,  187. — In  Oregon,  189. — California,  191. — Panama, 
193.— Rainless  Regions,  194.— Rainy  Side  of  Mountains,  199.— The  Ghauts,  200. 
— The  greatest  Precipitation — where  it  takes  place,  203. — Evaporation,  207. — Rate 
of,  in  India,  210. — Adaptations  of  the  Atmosphere,  219 70 


xviii  CONTENTS. 

CHAPTER  IV. 

LAND    AND    SEA    BREEZES. 

Lieutenant  Jansen,  <5»  228. — His  Contributions,  229. — The  Sea-breeze,  230. — An  Il- 
lustration, 231. — The  Land-breeze,  232. — Jansen's  Account  of  the  Land  and  Sea 
Breeze  in  the  East  Indies,  234.— A'Morning  Scene,  235.— The  Calm,  237.— The 
Inhabitants  of  the  Sea  going  to  Work,  239. — Noon,  240. — The  Sea-breeze  dies,  245. 
- — The  Land-breeze,  247. — A  Discussion,  248. — Why  Land  and  Sea  Breezes  are 
not  of  equal  Freshness  on  the  Sea-shore  of  all  Countries,  252. — The  Sea-breeze  at 
Valparaiso,  255.— The  Night,  258.— A  Contrast,  263 Page  104 

CHAPTER  V. 

RED    FOGS   AND    SEA    DUST. 

Where  found,  ^  266.— Tallies  on  the  Wind,  272.— Where  taken  up,  278.— Humboldt's 
Description,  282. — Questions  to  be  answered,  284. — What  Effects  the  Deserts  have 
upon  the  General  Circulation  of  the  Air,  286. — Information  derived  from  Sea  Dust, 
288.— Limits  of  Trade-winds,  289.— Breadth  of  Calm  Belts,  290 116 

CHAPTER  VI. 

ON   THE    PROBABLE    RELATION    BETWEEN   MAGNETISM    AND    THE    CIRCULATION    OF    THE 

ATMOSPHERE. 

Faraday's  Discoveries,  ^  299. — Is  there  a  crossing  of  Air  at  the  Calm  Belts'?  301. — 
Whence  comes  the  Vapor  for  Rains  in  extra-tropical  Regions  1  305. — Significant 
Facts,  310. — Wet  and  dry  Winds,  311. — Regions  of  Precipitation  and  Evaporation, 
312. — \Vhat  guides  the  Wind  in  his  Circulations  1  313. — Distribution  of  Rains  and 
Winds  not  left  to  Chance,  315. — A  Conjecture  about  Magnetism,  318. — Circum- 
stantial Evidence,  323.  —  More  Evaporating  Surface  in  the  Southern  than  in  the 
Northern  Hemisphere,  326. — Whence  come  the  Vapors  that  feed  the  great  Rivers 
with  Rains  1  329. — Rain  and  Thermal  Maps,  330. — The  Dry  Season  in  California, 
the  Wet  in  the  Mississippi  Valley,  332. — Importance  of  Meteorological  Observations 
in  British  America,  333. — Importance  of  extending  the  System  from  the  Sea  to  the 
Land,  334. — Climate  of  the  Interior,  335. — The  extra-tropical  Regions  of  the  North- 
ern Hemisphere  Condenser  for  the  Trade-winds  of  the  Southern,  336. — Plate  VII., 
339. — Countries  most  favorable  for  having  Rains,  343. — How  does  the  Air  of  the 
-Northeast  and  Southeast  Trades  cross  in  the  Equatorial  Calms,  350. — Rain  for  the 
Mississippi  Valley,  357. — Blood  Rains,  372. — Track  of  the  Passat-Staub  on  Plate 
VII.,  374.— The  Theory  of  Ampere,  378.— Calm  Regions  about  the  Poles,  380.— 
The  Pole  of  maximum  Cold,  381 125 

CHAPTER  VII. 

CURRENTS    OF   THE    SEA. 

Governed  by  Laws,  <J  396.— The  Capacity  of  Water  to  convey  Heat,  399.— The  Red 
Sea  Current,  404.— The  per  centum  of  Salt  in  Sea  Water,  418.— The  Mediterra- 
nean Current,  423. — Under  Current  from,  424. — Admiral  Smyth's  Soundings,  426. — 
Lyell's  Views,  429. — Admiral  Smyth's  Views,  436. — Currents  of  the  Indian  Ocean, 
439._Gulf  Stream  of  the  Pacific,  441.— Its  resemblance  to  that  of  the  Atlantic, 
442. — An  ice-bearing  Current  between  Africa  and  Australia,  449. — Currents  of  the 


CONTENTS.  ^-^ 

Pacific,  451. — A  Sargasso  Sea  in  the  Pacific,  452. — Drift-wood  upon  the  Aleutian 
Islands,  453. — Cold   Ochotsk,  454. — Humboldt's   Current,  455. — Warm   Current 

in  the  South  Pacific,  456. — Equatorial  Currents  in  the  South  Pacific,  458. The 

Effect  of  Rain  and  Evaporation  upon  Currents,  459. — Under  Currents  of  the  Atlan- 
tic, 461. — Equilibrium  of  the  Sea  maintained  by  Currents,  467. — The  Brazil  Cur- 
rent, 469 _  Page  148 

CHAPTER  Vni. 

THE    OPEN    SEX    IN    THE    ARCTIC    OCEAN. 

The  Habit  of  Whalemen,  «$>  473.— Right  Whales  can  not  cross  the  Equator,  475. — An 
under  Current  into  the  Polar  Basin,  478.— Indications  of  a  Wami  Climate,  481. — 
De  Haven's  Water  Sky,  482.— The  open  Sea  of  Dr.  Kane,  484.— Drift  of  an  aban- 
doned Ship,  487 173 

CHAPTER  IX. 

THE    SALTS    OF    THE    SEA. 

Why  is  the  Sea  Salt?  ^91. — An  Hypothesis,  494. — The  Adaptations  of  the  Sea,  498. 
— Components  of  Sea  Water  every  where  alike,  500. — Proportion  of  solid  Contents, 
502. — The  Influence  of  Wind  upon  the  Circulation  of  the  Sea,  508. — The  Influence 
of  Heat,  511. — The  Influence  of  Evaporation,  517. — The  Influence  of  Precipitation, 
519. — Under  Current  from  the  Mediterranean  and  Red  Sea  due  to  the  Salts  of,  523. 
— Space  that  the  Salts  of  the  Sea  would  occupy  in  a  Solid  State,  527. — De  Haven's 
Drift  from  the  Arctic  Ocean,  530. — An  under  Current  flowing  into  it,  534. — The 
Water  Sky,  540. — Sea  Shells,  545, — Their  Agency  in  the  System  of  Oceanic  Circu- 
lation, 548. — They  assist  to  regulate  Climate,  557. — Compensation  in  the  Sea,  563. 
— Insects  of  the  Sea,  565. — Geological  Records  concerning  the  Salts  of  the  Sea, 
568. — Light  from  the  Bible,  571. — Whence  come  the  Salts  of  the  Seal  574. — Pro- 
fessor Chapman's  Experiments,  579 179 

CHAPTER  X. 

THE    EQUATORIAL    CLOUD-RING. 

The  "  Doldrums,"  ^  583.— Oppressive  Weather,  586.— Offices  of  the  Clouds,  587.— 
Weight  for  the  Wind,  589.  —  Galileo  and  the  Pump-maker,  590.  —  Temperature 
and  Pressure  under  the  Cloud- ring,  591.  —  Its  eflfect  upon  Climate,  596.  —  Its  Of- 
fices, 599. — Whence  come  the  Vapors  that  form  the  Cloud-ring  1  602. — Its  Appear- 
ance, 605 209 

CHAPTER  XI. 

ON   THE    GEOLOGICAL    AQENCY    OF    THE    WINDS. 

Nature  regarded  as  a  Whole,  ^  611. — The  Dead  Sea,  614. — Annual  fall  of  Rain  upon 
less  now  than  formerly,  615. — The  Caspian,  617. — The  great  American  Lakes,  622. 
—Gulf  of  Mexico,  its  Depth,  624.— The  Eflfect  of  cutting  off"  the  Gulf  Stream,  625. 
— ^Uprising  of  Continents,  627. — The  Causes  that  change  the  Water-level  of  a 
country,  633. — Foot-prints  of  the  Clouds,  638. — Andes  rising  from  the  Sea,  640. — 
Rains  for  Europe,  651. — Terrestrial  Adaptations,  655. — Evaporating  Force  in  the 
Mediterranean,  661. — Display  of  Harmony,  663. — The  Age  of  the  Andes  and  Dead 
Sea  compared,  671 220 

B 


XX 


CONTENTS. 


CHAPTER  XII. 

THE  DEPTHS  OF  THE  OCEAN. 

Soundings  by  other  Nations,  <$)  676. — Contrivances  for  Deep  Soundings,  678. — Clock- 
work,  679.— Torpedo,  680.— Magnetic  Telegraph,  681.— The  Myths  of  the  Sea, 
683. — Attempts  to  Sound,  688. — The' Observatory  Plan  for  Sounding,  690. — Prac- 
tical Difficulties,  692. — Oceanic  Circulation,  695. — Law  of  Plummet's  Descent,  698. 
— Brooke's  Sounding  Apparatus,  700. — Greatest  Depths  yet  reached,  701. — Speci- 
mens from  the  Pacific,  703 Page  240 

CHAPTER  XIIL 

THE    BASIN    OF    THE    ATLANTIC. 

Us  Shape,  (}  704.— Plate  XL,  709.— The  deepest  Part  of  the  Atlantic,  710.--The  Use 
of  Deep-sea  Soundings,  713. — The  telegraphic  Plateau,  714. — It  extends  around 
the  Earth  as  a  Ridge,  715. — The  first  Specimens  with  Brooke's  Lead,  717. — The 
Bottom  of  the  Sea  a  Burial-place,  724. — The  leveling  Agencies  at  work  there,  730. 
— Marine  Insects  presented  in  a  new  Light,  734. — Conservators  of  the  Sea,  739.— 
Calcareous  Shells,  742.— Tallying  marine  Currents,  745.— A  Cast  of  7000  Fathoms 
in  the  Indian  Ocean,  750. — Bottom  from  the  Coral  Sea,  751. — Microscopic  Exam- 
ination of,  753.— The  Bed  of  the  Ocean,  761 251 

CHAPTER  XIV. 

THE    WINDS. 

Belt  of  Southeast  broader  than  Northeast,  <$>  764. — Tracks  of  Vessels  across  the  South- 
east Trades,  767. — Scenes  in  the  Trade-wind  Regions,  770. — The  Effect  of  South 
Africa  and  America  upon  the  Winds,  779. — Monsoons,  787. — Dove's  Theory,  789. 
— Proof  that  the  Southwest  Monsoons  are  the  Southeast  Trades  deflected,  797. — 
Hov/  the  Southwest  Monsoons  march  toward  the  Equator,  806. — How  the  Monsoon 
Season  may  be  known,  809. — Influence  of  Deserts  upon  the  Winds,  810. — Chang- 
ing of  the  Monsoons,  819. — West  Monsoon  in  Java  Sea,  823. — Water-spouts,  826. 
— Influence  of  Currents  upon  Winds,  829. — The  Calm  Belts,  835. — The  Equatorial 
Calms,  837.— The  Horse  Latitudes,  840.— The  Westerly  Winds,  843.— The  brave 
West  Winds  of  the  Southern  Hemisphere,  846 266 

CHAPTER  XV. 

CLIMATES    OF    THE    OCEAN. 

Milky  Way  of  the  Sea,  ^  848. — Contrasted  with  Climates  Ashore,  852. — Movements 
of  Isotherms,  854. — Mean  Temperature  of  Sea  and  Air,  860. — Rain  in  high  Lati- 
tudes at  Sea,  863. — Climate  of  England  affected  by  Coast  Line  of  Brazil,  871. — 
The  Gulf  of  Guinea,  875. — Summer  in  the  Northern  Hemisphere  hotter  than  in  the 
Southern,  883. — A  Harbor  for  Icebergs,  884. — Course  of  the  Isothermal  Line  across 
the  Atlantic,  887 294 

CHAPTER  XVI. 

THE    DRIFT    OF    THE    SEA. 

Data  used  for  Plate  IX.,  ^  893.— The  Antarctic  Flow,  896.— A  large  Flow  from  the 
Indian  Ocean,  902. —  Patches  of  colored  Water,  905.  —  The  Lagullas  Current, 


CONTENTS.  -jj^^ 

909.— An  immense  Current,  911.— Tide  Rips,  914.— Pulse  of  the  Sea,  920.— 
Diurnal  Change  of  Sea  Temperature,  922. — The  Fisheries,  925. — The  Sperm 
Whale,  926 Page  308 

CHAPTER  XVII. 

STORMS. 

Data  for  Plate  V.,  ^  929.— Typhoons,  936.— Monsoons  in  the  China  Sea,  937.— Mau- 
ritius Hurricanes,  938. — West  India,  ditto,  939. — Jansen  on  Hurricanes  and  Cy- 
clones, 940. — Extra-tropical  Gales,  950. — The  Steamer  San  Francisco's  Gale,  951. 
— More  Rains,  Gales,  &c.,  in  the  North  than  in  the  South  Atlantic  (Plate 
XIII.),  956 326 

CHAPTER  XVIII. 

ROUTES. 

How  Passages  have  been  shortened,  ^  959. — How  closely  Vessels  follow  each  other's 
Track,  961. — The  Archer  and  the  Flying  Cloud,  962. —  The  great  Race-course  upon 
the  Ocean,  964. — Description  of  a  Ship-race,  966. — Present  Knowledge  of  the 
Winds  enables  the  Navigator  to  compute  his  Detour,  991 336 

CHAPTER  XIX. 

A    LAST    WORD. 

Brussels  Conference,  §  996. — How  Navigators  may  obtain  a  Set  of  the  Maury  Charts, 
•  997.— The  Abstract  Log,  998 345 

AiJdenda 359 


APPENDIX. 

The  Atlantic  Telegraph 361 


EXPLANATION  OF  THE  PLATES. 

Plate  I.  (p.  75)  is  a  diagram  to  illustrate  the  circulation  of  the  atmosphere  (Chap. 
III.).  The  arrows  and  bands  within  the  circumference  of  the  circle  are  intended  to 
show  the  calm  belts,  and  prevailing  direction  of  the  wind  on  each  section  of  those 
belts.  The  arrows  exterior  to  the  periphery  of  the  circle— which  is  a  section  of  the 
earth  supposed  to  be  made  in  the  plane  of  the  meridian — are  intended  to  show  the 
direction  of  the  upper  and  lower  strata  of  winds  in  the  general  system  of  atmospher- 
ical circulation  ;  and  also  to  illustrate  how  the  air  brought  by  each  stratum  to  the 
calm  belts  there  ascends  or  descends,  as  the  case  may  be  ;  and  then,  continuing  to 
flow  on,  how  it  crosses  over  in  the  direction  in  v/hich  it  was  traveling  when  it  arrived 
at  the  calm  zone. 

Plates  II.  and  III.  (p.  250)  are  drawings  of  Brooke's  Deep-sea  Sounding  Appa- 
ratus, for  bringing  up  specimens  of  the  bottom  [^  701). 

Plate  IV.  (p.  293)  is  intended  to  illustrate  the  extreme  movements  of  the  isotherms 
50°,  60°,  70°,  &c.,  in  the  Atlantic  Ocean  during  the  year.  The  connection  between 
the  law  of  this  motion  and  the  climates  of  the  sea  is  exceedingly  interesting. 

Plate  V.  is  a  section  taken  from  one  of  the  manuscript  charts  at  the  Observatory. 
It  illustrates  the  method  adopted  there  for  co-ordinating  for  the  Pilot  Charts  the  winds 
as  reported  in  the  abstract  logs.  For  this  purpose  the  ocean  is  divided  into  conven- 
ient sections,  usually  five  degrees  of  latitude  by  live  degrees  of  longitude.  These  par- 
allelograms are  then  subdivided  into  a  system  of  engraved  squares,  the  months  of  the 
year  being  the  ordinates,  and  the  points  of  the  compass  being  the  abscissse.  As  the 
wind  is  reported  by  a  vessel  that  passes  through  any  part  of  the  parallelogram,  so  it 
is  assumed  to  have  been  at  that  time  all  over  the  parallelogram.  From  such  investi- 
gations as  this  the  Pilot  Charts  (<$»  929)  are  constructed. 

Plate  VI.  illustrates  the  position  of  the  channel  of  the  Gulf  Stream  (Chap.  I.)  for 
summer  and  winter.  The  diagram  A  shows  a  thermometrical  profile  presented  by 
cross-sections  of  the  Gulf  Stream,  according  to  observations  made  by  the  hydrograph- 
ical  parties  of  the  United  States  Coast  Survey.  The  elements  for  this  diagram  were 
kindly  furnished  me  by  the  superintendent  of  that  work.  They  are  from  a  paper  on 
the  Gulf  Stream,  read  by  him  before  the  American  Association  for  the  Advancement 
of  Science  at  its  meeting  in  "Washington,  1854.  Imagine  a  vessel  to  sail  from  the 
Capes  of  Virginia  straight  out  to  sea,  crossing  the  Gulf  Stream  at  right  angles,  and 
taking  the  temperature  of  its  waters  at  the  surface  and  at  various  depths.  The  dia- 
gram shows  the  elevation  and  depression  of  the  thermometer  across  this  section  as 
they  were  actually  observed  by  such  a  vessel. 

The  black  lines  x,  y,  z,  in  the  Gulf  Stream,  show  the  course  which  those  threads 

of  warm  waters  take  (<^  57).     The  lines  a,  h  show  the  computed  drift  route  that  the 

unfortunate  steamer  San  Francisco  would  take  after  her  terrible  disaster  in  December, 

1853. 

.  Plate  VII.  is  intended  to  show  how  the  winds  may  become  geological  agents.     It 


EXPLANATION  OF  THE  PLATES.  xxiii 

shows  where  the  winds  that,  in  the  general  system  of  atmospherical  circulation,  blow 
over  the  deserts  and  thirsty  lands  in  Asia  and  Africa  (where  the  annual  amount  of 
precipitation  is  small)  arc  supposed  to  get  their  vapors  from  ;  where,  as  surface  winds, 
they  are  supposed  to  condense  portions  of  it ;  and  whither  they  are  supposed  to  trans- 
port the  residue  thereof  through  the  upper  regions,  retaining  it  until  they  again  be- 
come surface  winds. 

Plate  VIIL  shows  the  prevailing  direction  of  the  wind  during  the  year  in  all  parts 
of  the  ocean,  as  derived  from  the  series  of  investigations  illustrated  on  Plate  VIL  It 
also  shows  the  principal  routes  across  the  seas  to  various  places.  Where  the  cross- 
lines  representing  the  yards  are  oblique  to  the  keel  of  the  vessel,  they  indicate  that 
the  winds  are,  for  the  most  part,  ahead  ;  when  perpendicular  or  square,  that  the  winds 
are,  for  the  most  part,  fair.  The  figures  on  or  near  the  diagrams  representing  the 
vessels  show  the  average  length  of  the  passage  in  days. 

The  arrows  denote  the  prevailing  direction  of  the  wind ;  they  are  supposed  to  fly 
with  it ;  so  that  the  wind  is  going  as  the  arrows  point.  The  half-bearded  and  half- 
feathered  arrows  represent  monsoons  (<$>  763),  and  the  stippled  or  shaded  belts  the 
calm  zones. 

In  the  regions  on  the  polar  side  of  the  calms  of  Capricorn  and  of  Cancer,  where 
the  arrows  are  flying  both  from  the  northwest  and  the  southwest,  the  idea  intended 
to  be  conve}' ed  is,  that  the  prevailing  direction  of  the  wind  is  between  the  northwest 
and  the  southwest,  and  that  their  frequency  is  from  these  two  quarters  in  proportion 
to  the  number  of  arrows. 

Plate  IX.  is  intended  to  show  the  present  state  of  our  knowledge  with  regard  to 
the  drift  of  the  ocean,  or,  more  properly,  with  regard  to  the  great  flow  of  polar  and 
equatorial  waters,  and  their  channels  of  circulation  as  indicated  by  the  thermometer 
(i^  889).  Further  researches  will  enable  us  to  improve  this  chart.  The  most  favorite 
places  of  resort  for  the  whale — right  in  cold,  and  sperm  in  warm  water — are  also  ex- 
hibited on  this  chart. 

Plate  X.  exhibits  the  actual  path  of  a  storm,  which  is  a  type  (§  85)  of  the  West 
India  hurricanes.  Mr.  Redfield,  Colonel  Reid,  and  others,  have  traced  out  the  paths 
of  a  number  of  such  storms.  All  of  this  class  appear  to  make  for  the  Gulf  Stream  ; 
after  reaching  it,  they  turn  about  and  follow  it  in  their  course  {^  95). 

Mr.  Piddington,  of  Calcutta,  has  made  the  East  India  hurricanes,  which  are  similar 
to  these,  the  object  of  special,  patient,  and  laborious  investigation.  He  calls  them 
cyclones,  and  has  elicited  much  valuable  information  concerning  them,  which  may  be 
found  embraced  in  his  "  Sailor's  Horn-book,"  "  Conversations  about  Hurricanes,"  and 
numerous  papers  pubUshed  from  time  to  time  in  the  Journal  of  the  Asiatic  Society. 

Plates  XI.  and  XII.  speak  for  themselves.  They  are  orographic  for  the  North 
Atlantic  Ocean,  and  exhibit  completely  the  present  state  of  our  knowledge  with  re- 
gard to  the  elevations  and  depressions  in  the  bed  of  the  sea;  Plate  XII.  exhibiting  a 
vertical  section  of  the  Atlantic,  and  showing  the  contrasts  of  its  bottom  with  the  sea- 
level  in  a  line  from  Mexico  across  Yucatan,  Cuba,  San  Domingo,  and  the  Cape  de 
Verds,  to  the  coast  of  Africa,  marked  A  on  Plate  XI. 

Plate  XIII. — The  data  for  this  Plate  are  furnished  by  Maury's  Storm  and  Rain 
Charts,  including  observations  for  107,277  days  in  the  North  Atlantic,  and  158,025  in 
the  South  ;  collated  by  Lieutenant  J.  J.  Guthrie,  at  the  Washington  Observatory,  in 
1855. 

The  heavy  vertical  lines,  5°,  10°,  15°,  etc.,  represent  parallels  of  latitude,  the  other 


xxiv  EXPLANATION  OF  THE  PLATES. 

vertical  lines,  months;  and  the  horizontal  lines,  per  cents.,  or  the  number  of  days  in 
a  hundred. 

The  continuous  curve  line  stands  for  phenomena  in  the  North,  and  the  broken  curve 
line  for  phenomena  in  the  South  Atlantic.  Thus  the  Gales'  Curve  shows  that  in  every 
hundred  days,  and  on  the  average,  in  tjje  month  of  January  of  different  years,  there 
have  been  observed,  in  the  northern  hemisphere,  36  gales  (36  per  cent.)  between  the 
parallels  of  50°  and  55° ;  whereas  during  the  same  time  and  between  the  same  par- 
allels in  the  southern  hemisphere,  only  10  gales  on  the  average  (10  per  cent.)  have 
been  reported. 

The  fact  is  here  developed  that  the  atmosphere  is  in  a  more  unstable  condition  in 
the  North  than  in  the  South  Atlantic ;  that  we  have  more  calms,  more  rains,  more 
fogs,  more  gales,  and  more  thunder  in  the  northern  than  in  the  southern  hemisphere, 
particularly  between  the  equator  and  the  55th  parallel.  Beyond  that  the  influence 
of  Cape  Horn  becomes  manifest. 


THE 


PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  I. 

THE    GULF    STREAM. 

Its  Color,  ^  2. — Theories,  5. — Capt.  Livingston's,  6. — Dr.  Franklin's,  7. — Admiral 
Smyth  and  Mediterranean  Currents,  8. — Trade  Winds  not  the  Cause  of  the  Gulf 
Stream,  9. — Drift  of  Bottles,  12. — Sargasso  Sea,  13. — Hypothetical  System  of  Cur- 
rents, 19. — Galvanic  Properties  of  the  Gulf  Stream,  26. — Saltness  of  ditto,  29. — 
Effects  produced  upon  Currents  by  Evaporation,  32. — Gulf  Stream  Roof-shaped, 
39. — Effects  of  Diurnal  Rotation  upon  Running  Water,  42. — Course  of  the  Gulf 
Stream  not  altered  by  Nantucket  Shoals,  52. — The  Trough  in  the  Sea  through  which 
the  Gulf  Stream  flows  has  a  Vibratory  Motion,  54. — Streaks  of  Warm  and  Cold  Wa- 
ter in  the  Gulf  Stream,  57. — Runs  up  Hill,  59. — A  Cushion  of  Cold  W^ater,  60. 

1.  There  is  a  river  in  the  ocean.  In  the  severest  droughts  it 
never  fails,  and  in  the  mightiest  floods  it  never  overflows.  Its 
banks  and  its  bottoms  are  of  cold  water,  while  its  current  is  of 
warm.  The  Gulf  of  Mexico  is  its  fountain,  and  its  mouth  is  in 
the  Arctic  Seas.  It  is  the  Gulf  Stream.  There  is  in  the  world 
no  other  such  majestic  flow  of  waters.  Its  current  is  more  rapid 
than  the  ]\Iississippi  or  the  Amazon,  and  its  volume  more  than  a 
thousand  times  greater. 

2.  Its  waters,  as  far  out  from  the  Gulf  as  the  Carolina  coasts, 
are  of  an  indigo  blue.  They  are  so  distinctly  marked  that  their 
line  of  junction  witli  the  common  sea- water  may  be  traced  by  the 
eye.  Often  one  half  of  the  vessel  may  be  perceived  floating  in 
Gulf  Stream  water,  while  the  other  half  is  in  common  water  of  the 
sea ;  so  sharp  is  the  line,  and  such  the  want  of  affinity  between 
those  waters,  and  such,  too,  the  reluctance,  so  to  speak,  oil  the  part 
of  those  of  the  Gulf  Stream  to  mingle  with  the  common  water  of 
the  sea. 


26  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

3.  At  the  salt-works  in  France,  and  along  the  shores  of  the 
Adriatic,  where  the  ''salines'^  are  carried  on  by  the  process  of  so- 
lar evaporation,  there  is  a  series  of  vats  or  pools  through  which 
the  w^ater  is  passed  as  it  comes  from  the  sea,  and  is  reduced  to 
the  briny  state.  The  longer  it  is' exposed  to  evaporation,  the  Salter 
it  grows,  and  the  deeper  is  the  hue  of  its  blue,  until  crystallization 
is  about  to  commence,  when  the  now  deep  blue  water  puts  on  a 
reddish  tint.  Now  the  waters  of  the  Gulf  Stream  are  Salter  (§  29) 
than  the  waters  of  the  sea  through  which  they  flow,  and  hence  we 
can  account  for  the  deep  indigo  blue  which  all  navigators  observe 
off  the  Carolina  coasts. 

4.  These  salt-makers  are  in  the  habit  of  judging  of  the  richness 
of  the  sea- water  in  salt  by  its  color — the  greener  the  hue,  the  fresh- 
er the  water.  We  have  in  this,  perhaps,  an  explanation  of  the 
contrasts  which  the  waters  of  the  Gulf  Stream  present  with  those 
of  the  xitlantic,  as  well  as  of  the  light  green  of  the  North  Sea  and 
other  Polar  waters ;  also  of  the  dark  blue  of  the  trade-wind  re- 
gions, and  especially  of  the  Indian  Ocean,  which  poets  have  de- 
scribed as  the  "black  waters." 

5.  What  is  the  cause  of  the  Gulf  Stream  has  always  puzzled 
philoso^ohers.  Many  are  the  theories  and  numerous  the  specula- 
tions that  have  been  advanced  with  regard  to  it.  ]\Iodern  inves- 
tigations and  examinations  are  beginning  to  throw  some  light  upon 
the  subject,  though  all  is  not  yet  clear. 

Early  writers  maintained  that  the  Mississippi  River  was  the 
father  of  the  Gulf  Stream.  Its  floods,  they  said,  produce  it ;  for 
its  velocity,  it  was  held,  could  be  computed  by  the  rate  of  the  cur- 
rent of  the  river. 

6.  Captain  Livingston  overturned  this  hypothesis  by  showing 
that  the  volume  of  water  which  the  Mississippi  Eiver  empties  into 
the  Gulf  of  ]\Iexico  is  not  equal  to  the  three  thousandth  part  of 
that  which  escapes  from  it  through  the  Gulf  Stream. 

Moreover,  the  water  of  the  Gulf  Stream  is  salt — that  of  the 
Mississippi,  fresh;  and  those  philosophers  (§  5)  forgot  that  just  as 
much  salt  as  escapes  from  the  Gulf  of  Mexico  through  this  stream, 
must  enter  the  Gulf  through  some  other  channel  from  the  main 
ocean ;  for,  if  it  did  not,  the  Gulf  of  Mexico,  in  process  of  time, 


THE  GULF  STREAM.  27 

unless  it  had  a  ssil  bed  at  the  bottom,  or  was  fed  with  salt  springs 
from  below — neither  of  which  is  probable — would  become  a  fresh- 
water basin. 

The  above  quoted  argument  of  Captain  Livingston,  however, 
was  held  to  be  conclusive  ;  and  upon  the  remains  of  the  hypoth- 
esis which  he  had  so  completely  overturned,  he  set  up  another, 
which,  in  turn,  has  been  upset.  In  it  he  ascribed  the  velocity  of 
the  Gulf  Stream  as  depending  "on  the  motion  of  the  sun  in  the 
ecliptic,  and  the  influence  he  has  on  the  waters  of  the  Atlantic." 

7.  But  the  opinion  that  came  to  be  the  most  generally  received 
and  deep-rooted  in  the  mind  of  seafaring  people  was  the  one  re- 
peated by  Dr.  Franklin,  and  which  held  that  the  Gulf  Stream  is 
the  escaping  of  the  waters  that  have  been  forced  into  the  Carib- 
bean Sea  by  the  trade-winds,  and  that  it  is  the  pressure  of  those 
winds  upon  the  water  which  forces  up  into  that  sea  a  head,  as  it 
were,  for  this  stream. 

We  know  of  instances  in  which  waters  have  been  accumulated 
on  one  side  of  a  lake,  or  in  one  end  of  a  canal,  at  the  expense  of 
the  other.  The  pressure  of  the  trade-winds  may  assist  to  give  the 
Gulf  Stream  its  initial  velocity,  but  are  they  of  themselves  ade- 
quate to  such  an  effect  ?  To  my  mind,  the  laws  of  Hydrostatics, 
as  at  present  expounded,  appear  by  no  means  to  warrant  the  con- 
clusion that  it  is,  unless  the  aid  of  other  as-ents  also  be  broug-ht 

'  DO 

to  bear. 

8.  Admiral  Smyth,  in  his  valuable  memoir  on  the  jMediterra- 
nean  (p.  162),  mentions  that  a  continuance  in  the  Sea  of  Tuscany 
of  '•'gusty  gales'^  from  the  southwest  has  been  known  to  raise  its 
surface  no  less  than  twelve  feet  above  its  ordinary  level.  This, 
he  says,  occasions  a  strong  surface  drift  through  the  Strait  of  Bo- 
nifaccio.  But  in  this  we  have  nothing  like  the  Gulf  Stream ;  no 
deep  and  narrow  channel-way  ta  conduct  these  waters  off  like  a 
miniature  river  even  in  that  sea,  but  a  mere  surface  flow,  such  as 
usually  follows  the  piling  up  of  water  in  any  pond  or  gulf  above 
the  ordinary  level.  The  Bonifaccio  current  does  not  flow  like  a 
"river  in  the  sea"  across  the  Mediterranean,  but  it  spreads  itself 
out  as  soon  as  it  passes  the  Straits,  and,  like  a  circle  on  the  water, 
loses  itself  by  broad  spreading  as  soon  as  it  finds  sea  room. 


28  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

9.  Supposing  the  pressure  of  the  waters  that  are  forced  into 
the  Caribbean  Sea  by  the  trade-winds  to  be  the  sole  cause  of  the 
Gulf  Stream,  that  sea  and  the  Mexican  Gulf  should  have  a  much 
higher  level  than  the  Atlantic.  Accordingly,  the  advocates  of 
this  theory  require  for  its  support  "a  great  degree  of  elevation." 
Major  Itennell  likens  the  stream  to  "  an  immense  river  descend- 
ing from  a  higher  level  into  a  plain."  Now  we  know  very  nearly 
the  average  breadth  and  velocity  of  the  Gulf  Stream  in  the  Florida 
Pass.  We  also  know,  with  a  like  degree  of  approximation,  the 
A^elocity  and  breadth  of  the  same  waters  off  Cape  Hatteras.  Their 
breadth  here  is  about  seventy-five  miles  against  thirty-two  in  the 
^'  Narrows"  of  the  Straits,  and  their  mean  velocity  is  three  knots 
off  Hatteras  against  four  in  the  "  Narrows."  This  being  the  case, 
it  is  easy  to  show  that  the  depth  of  the  Gulf  Stream  off  Hatteras 
is  not  so  great  as  it  is  in  the  "Narrows"  of  Bemini  by  nearly  50 
per  cent.,  and  that,  consequently,  instead  of  descending^  its  bed 
represents  the  surface  of  an  inclined  plane,  with  its  descent  in- 
clined from  the  north  toward  the  south,  zi])  which  plane  the  lower 
depths  of  the  stream  must  ascend.  If  we  assume  its  depth  off 
Bemini*  to  be  two  hundred  fathoms,  which  are  thought  to  be  with- 
in limits,  the  above  rates  of  breadth  and  velocity  will  give  one 
hundred  and  fourteen  fathoms  for  its  depth  off  Hatteras.  The 
waters,  therefore,  which  in  the  Straits  are  below  the  level  of  the 
Hatteras  depth,  so  far  from  descending^  are  actually  forced  up  an 
inclined  plane,  whose  submarine  ascent  is  not  less  than  ten  inches 
to  the  mile. 

10.  The  Niagara  is  an  "immense  river  descending  into  a  plain." 
But  instead  of  preserving  its  character  in  Lake  Ontario  as  a  dis- 
tinct and  well-defined  stream  for  several  hundred  miles,  it  spreads 
itself  out,  and  its  waters  are  immediately  lost  in  those  of  the  lake. 
Why  should  not  the  Gulf  Stream  do  the  same?  It  gradually 
enlarges  itself,  it  is  true  ;  but,  instead  of  mingling  with  the  ocean 
by  broad  spreading,  as  the  "immense  rivers"  descending  into  the 
northern  lakes  do,  its  waters,  like  a  stream  of  oil  in  the  ocean,  pre- 
serve a  distinctive  character  for  more  than  three  thousand  miles. 

*  Professor  Bache  reports  that  the  officers  of  the  Coast  Survey  have  sounded  with 
the  deep  sea  lead,  and  ascertained  its  depth  here  to  be  370  fathoms  (January,  1856). 


THE  GULF  STREAM.  29 

11.  ]\Ioreover,  while  the  Gulf  Stream  is  running  to  the  north 
from  its  supposed  elevated  level  at  the  south,  there  is  a  cold  cur- 
rent coming  down  from  the  north ;  meeting  the  warm  waters  of 
the  Gulf  midway  the  ocean,  it  divides  itself,  and  runs  by  the  side 
of  them  right  back  into  those  very  reservoirs  at  the  south,  to  which 
theory  gives  an  elevation  sufficient  to  send  out  entirely  across  the 
Atlantic  a  jet  of  warm  water  said  to  be  more  than  three  thousand 
times  greater  in  volume  than  the  Mississippi  River.  This  current 
from  Baffin's  Bay  has  not  only  no  trade-winds  to  give  it  a  head, 
but  the  prevailing  winds  are  unfavorable  to  it,  and  for  a  great  part 
of  the  way  it  is  below  the  surface,  and  far  beyond  the  propelling 
reach  of  any  wind.  And  there  is  every  reason  to  believe  that  this, 
with  other  polar  currents,  is  quite  equal  in  volume  to  the  Gulf 
Stream.  Are  they  not  the  effects  of  like  causes  ?  If  so,  what 
have  the  trade-winds  to  do  with  the  one  more  than  the  other  ? 

12.  It  is  a  custom  often  practiced  by  seafaring  people  to  throw 
a  bottle  overboard,  with  a  paper,  stating  the  time  and  place  at 
which  it  is  done.  In  the  absence  of  other  information  as  to  cur- 
rents, that  affiDrded  by  these  mute  little  navigators  is  of  great 
value.  They  leave  no  tracks  behind  them,  it  is  true,  and  their 
routes  can  not  be  ascertained.  But  knowing  where  they  were 
cast,  and  seeing  where  they  are  found,  some  idea  may  be  formed 
as  to  their  course.  Straight  lines  may  at  least  be  drawn,  show- 
ing the  shortest  distance  from  the  beginning  to  the  end  of  their 
voyage,  with  the  time  elapsed.  Admiral  Beechey,  R.  N.,  has  pre- 
pared a  chart,  representing,  in  this  way,  the  tracks  of  more  than 
one  hundred  bottles.  From  it,  it  appears  that  the  waters  from 
every  quarter  of  the  Atlantic  tend  toward  the  Gulf  of  Mexico  and 
its  stream.  Bottles  cast  into  the  sea  midway  between  the  Old 
and  the  New  Worlds,  near  the  coasts  of  Europe,  Africa,  and  Amer- 
ica, at  the  extremiC  north  or  farthest  south,  have  been  found  either 
in  the  West  Indies,  on  the  British  Isles,  or  within  the  weU-known 
range  of  Gulf  Stream  waters. 

Of  two  cast  out  together  in  south  latitude  on  the  coast  of  Africa, 
one  was  found  on  the  island  of  Trinidad  ;  the  other  on  Guernsey, 
in  the  English  Channel.  In  the  absence  of  positive  information 
on  the  subject,  the  circumstantial  evidence  that  the  latter  per- 


30  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

formed  the  tour  of  the  Gulf  is  all  but  conclusive.  And  there  is 
reason  to  suppose  that  some  of  the  bottles  of  the  admiral's  chart 
have  also  performed  the  tour  of  the  Gulf  Stream ;  then,  without 
being  cast  ashore,  have  returned  with  the  drift  along  the  coast  of 
Africa  into  the  inter-tropical  region  ;  thence  through  the  Caribbe- 
an Sea,  and  so  on  with  the  Gulf  Stream  again.     (Plate  YI.) 

Another  bottle,  thrown  over  off  Cape  Horn  by  an  American 
master  in  1837,  has  been  recently  picked  up  on  the  coast  of  Ire- 
land. An  inspection  of  the  chart,  and  of  the  drift  of  the  other 
bottles,  seems  to  force  the  conclusion  that  this  bottle  too  went 
even  from  that  remote  region  to  the  so-called  Jiigher  level  of  the 
Gulf  Stream  reservoir. 

13.  Midway  the  Atlantic,  in  the  triangular  space  between  the 
Azores,  Canaries,  and  the  Cape  de  Verd  Islands,  is  the  Sargasso 
Sea.  (Plate  YI.)  Covering  an  area  equal  in  extent  to  the  Mis- 
sissippi Yalley,  it  is  so  thickly  matted  over  with  Gulf  weeds  [fitcus 
natani)^  that  the  speed  of  vessels  passing  through  it  is  often  much 
retarded.  When  the  companions  of  Columbus  saw  it,  they  thought 
it  marked  the  limits  of  navigation,  and  became  alarmed.  To  the 
eye,  at  a  little  distance,  it  seems  substantial  enough  to  walk  upon. 
Patches  of  the  weed  are  always  to  be  seen  floating  along  the  outer 
edge  of  the  Gulf  Stream.  Now,  if  bits  of  cork  or  chaff,  or  any 
floating  substance,  be  put  into  a  basin,  and  a  circular  motion  be 
given  to  the  water,  all  the  light  substances  will  be  found  crowding 
together  near  the  centre  of  the  pool,  where  there  is  the  least  mo- 
tion. Just  sucli  a  basin  is  the  Atlantic  Ocean  to  the  Gulf  Stream ; 
and  the  Sargasso  Sea  is  the  centre  of  the  whirl.  '  Columbus  first 
found  this  weedy  sea  in  his  voyage  of  discovery  ;  there  it  has  re- 
mained to  this  day,  moving  up  and  down,  and  changing  its  position 
like  the  calms  of  Cancer,  according  to  the  seasons,  the  storms,  and 
the  winds.  Exact  observations  as  to  its  limits  and  their  range, 
extending  back  for  fifty  years,  assure  us  that  its  mean  position 
has  not  been  altered  since  that  time.  This  indication  of  a  cir- 
cular motion  by  the  Gulf  Stream  is  corroborated  by  the  bottle 
chart,  by  Plate  YI.,  and  other  sources  of  information.  If,  there- 
fore, this  be  so,  w^hy  give  the  endless  current  a  higher  level  in 
one  part  of  its  course  than  another  ? 


THE  GULF  STREAM.  3I 

14.  Nay,  more ;  at  the  very  season  of  the  year  when  tne  Gulf 
Stream  is  rushing  in  greatest  volume  through  the  Straits  of  Flor- 
ida, and  hastening  to  the  north  with  the  greatest  rapidity,  there  is 
a  cold  stream  from  Baffin's  Bay,  Labrador,  and  the  coasts  of  the 
north,  running  to  the  south  with  equal  velocity.  Where  is  the 
trade-wind  that  gives  the  higher  level  to  Baffin's  Bay,  or  that  even 
presses  upon,  or  assists  to  put  this  current  in  motion?  The  ao-en- 
cy  of  winds  in  producing  currents  in  the  deep  sea  must  be  very 
partial.  These  two  currents  meet  off  the  Grand  Banks,  where 
the  latter  is  divided.  One  part  of  it  underruns  the  Gulf  Strcani, 
as  is  shown  by  the  icebergs  which  are  carried  in  a  direction  tend- 
ing across  its  course.  The  probability  is,  that  this  "fork"  flows 
on  toward  the  south,  and  runs  into  the  Caribbean  Sea,  for  the 
temperature  of  the  water  at  a  little  depth  there  has  been  found  far 
below  the  mean  temperature  of  the  earth's  crust,  and  quite  as  cold 
as  at  a  corresponding  depth  off  the  Arctic  shores  of  Spitzbergen. 

15.  More  water  can  not  run  from  the  equator  or  the  pole  than 
to  it.  If  we  make  the  trade-mnds  to  cause  the  Gulf  Stream,  we 
ought  to  have  some  other  w^ind  to  produce  the  Polar  flow ;  but 
these  currents,  for  the  most  part,  and  for  great  distances,  are  suh- 
mariiie,  and  therefore  beyond  the  influence  of  winds.  Hence  it 
should  appear  that  vyincls  have  little  to  do  with  the  general  system 
of  aqueous  circulation  in  the  ocean. 

The  other  "fork"  runs  between  us  and  the  Gulf  Stream  to  the 
south,  as  already  described.  As  far  as  it  has  been  traced,  it  war- 
rants the  belief  that  it,  too,  runs  ujp  to  seek  the  so-called  higher 
level  of  the  Mexican  Gulf. 

16.  The  power  necessary  to  overcome  the  resistance  opposed 
to  such  a  body  of  water  as  that  of  the  Gulf  Stream,  running  sev- 
eral thousand  miles  without  any  renewal  of  impulse  from  the  forces 
of  gravitation  or  any  other  known  cause,  is  truly  surprising.  It 
so  happens  that  we  have  an  argument  for  determining,  with  con- 
siderable accuracy,  the  resistance  which  the  waters  of  this  stream 
meet  with  in  their  motion  toward  the  east.  Owing  to  the  diurnal 
rotation,  they  are  carried  around  with  the  earth  on  its  axis  toicard 
the  east  with  an  hourly  velocity  of  one  hundred  and  fifty-seven* 

*  In  this  calculation  the  earth  is  treated  as  a  perfect  sphere,  with  a  diameter  of 
7925-56  miles. 


32        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

miles  greater  when  they  enter  the  Atlantic  than  when  they  arrive 
off  the  Banks  of  Newfoundland  ;  for  in  consequence  of  the  differ- 
ence of  latitude  between  the  parallels  of  these  two  places,  their 
rate  of  motion  around  the  axis  of  the  earth  is  reduced  from  nine 
hundred  and  fifteen*  to  seven' hundred  and  fifty-eight  miles  the 
hour. 

17.  Therefore  this  immense  volume  of  water  would,  if  we  sup- 
pose it  to  pass  from  the  Bahamas  to  the  Grand  Banks  in  an  hour, 
meet  with  an  ojDposing  force  in  the  shape  of  resistance  sufficient, 
in  the  aggregate,  to  retard  it  two  miles  and  a  half  the  minute  in  its 
eastwardly  rate.  If  the  actual  resistance  be  calculated  according 
to  received  laws,  it  will  be  found  equal  to  several  atmospheres. 
And  by  analogy,  how  inadequate  must  the  pressure  of  the  gentle 
trade-winds  be  to  such  resistance,  and  to  the  effect  assigned  them  ? 
If,  therefore,  in  the  proposed  inquiry,  we  search  for  a  propelling 
power  nowhere  but  in  the  higher  level  of  the  Gulf,  we  must  admit, 
in  the  head  of  water  there,  the  existence  of  a  force  capable  of  put- 
ting in  motion,  and  of  driving  over  a  plain  at  the  rate  of  four 
miles  the  hour,  all  the  waters,  as  fast  as  they  can  be  brought 
down  by  three  thousand  (§6)  such  streams  as  the  Mississippi 
River — a  power,  at  least,  sufficient  to  overcome  the  resistance  re- 
quired to  reduce  from  two  miles  and  a  half  to  a  few  feet  per  min- 
ute the  velocity  of  a  stream  that  keeps  in  perpetual  motion  one 
fourth  of  all  the  waters  in  the  Atlantic  Ocean. 

18.  The  facts,  from  observation  on  this  interesting  subject,  af- 
ford us  at  best  but  a  mere  glimmer  of  light,  by  no  means  sufficient 
to  make  any  mind  clear  as  to  a  higher  level  of  the  Gulf,  or  as  to 
the  sufficiency  of  any  other  of  the  causes  generally  assigned  for 
this  wonderful  stream.  If  it  be  necessary  to  resort  to  a  higher 
level  in  the  Gulf  to  account  for  the  velocity  off  Hatteras,  I  can  not 
perceive  why  we  should  not,  with  like  reasoning,  resort  to  a  high- 
er level  off  Hatteras  also  to  account  for  the  velocity  off  the  Grand 
Banks,  and  thus  make  the  Gulf  Stream,  throughout  its  circuit,  a 
descending  current,  and,  by  the  reductio  ad  ahsurdum,  show  that 

*  Or,  915-26  to  75860.  On  the  latter  parallel  the  current  has  an  east  set  of  about 
one  and  a  half  miles  the  hour,  making  the  true  velocity  to  the  east,  and  on  the  axis 
of  the  earth,  about  seven  hundred  and  sixty  miles  an  hour  at  the  Grand  Banks. 


THE  GULF  STREAM.  33 

the  trade-winds  are  not  adequate  to  the  effect  ascribed.  ^lore- 
over,  the  top  of  the  Gulf  Stream  runs  on  a  level  with  the  ocean, 
therefore  we  know  it  is  not  a  descending  current. 

19.  When  facts  are  wanting,  it  often  happens  that  hypothesis 
will  serve,  in  their  stead,  the  purposes  of  illustration.  Let  us, 
therefore,  suppose  a  globe  of  the  earth's  size,  having  a  solid  nu- 
cleus, and  covered  all  over  with  water  two  hundred  fathoms  deep, 
and  that  every  source  of  heat  and  cause  of  radiation  be  removed, 
so  that  its  fluid  temperature  becomes  constant  and  uniform 
throughout.  On  such  a  globe,  the  equilibrium  remaining  undis- 
turbed, there  would  be  neither  wind  nor  current. 

20.  Let  us  now  suppose  that  all  the  water  within  the  tropics, 
to  the  depth  of  one  hundred  fathoms,  suddenly  becomes  oil.  The 
aqueous  equilibrium  of  the  planet  would  thereby  be  disturbed, 
and  a  general  system  of  currents  and  counter  currents  would  be 
immediately  commenced — the  oil,  in  an  unbroken  sheet  on  the 
surface,  running  toward  the  poles,  and  the  water,  in  an  under  cur- 
rent, toward  the  equator.  The  oil  is  supposed,  as  it  reaches  the 
polar  basin,  to  be  reconverted  into  water,  and  the  water  to  be- 
come oil  as  it  crosses  Cancer  and  Capricorn,  rising  to  the  surface 
in  the  intertropical  regions  and  returning  as  before. 

21.  Thus,  loithout  icind,  we  should  have  a  perpetual  and  uni- 
form system  of  tropical  and  polar  currents.  Li  consequence  of 
diurnal  rotation  of  the  planet  on  its  axis,  each  particle  of  oil,  were 
resistance  small,  would  approach  the  poles  on  a  spiral  turning  to 
the  east,  with  a  relative  velocity  greater  and  greater,  until,  finally, 
it  would  reach  the  pole,  and  whirl  about  it  at  the  rate  of  nearly  a 
thousand  miles  the  hour.  Becoming  water  and  losing  its  velocity, 
it  would  approach  the  tropics  by  a  similar,  but  inverted  spiral, 
turning  toward  the  west.  Owing  to  the  principle  here  alluded  to, 
all  currents  from  the  equator  to  the  poles  should  have  an  eastward 
tendency,  and  all  from  the  poles  toward  the  equator  a  westward. 

22.  Let  us  now  suppose  the  solid  nucleus  of  this  hypothetical 
globe  to  assume  the  exact  form  and  shape  of  the  bottom  of  our 
seas,  and  in  all  respects,  as  to  figure  and  size,  to  represent  the 
shoals  and  islands  of  the  sea,  as  well  as  the  coast  lines  and  con- 
tinents of  the  earth.     The  uniform  system  of  currents  just  de- 


34  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

scribed  would  now  be  interrupted  by  obstructions  and  local  causes 
of  various  kinds,  such  as  unequal  depth  of  water,  contour  of  shore- 
lines, &c. ;  and  we  should  have  at  certain  places  currents  greater 
in  volume  and  velocity  than  at  others.  But  still  there  would  be 
a  system  of  currents  and  counter  currents  to  and  from  either  pole 
and  the  equator.  Now  do  not  the  cold  waters  of  the  north,  and 
the  warm  waters  of  the  Gulf,  made  specifically  lighter  by  tropical 
heat,  and  which  we  see  actually  preserving  such  a  system  of  coun- 
ter currents,  hold,  at  least  in  some  degree,  the  relation  of  the  sup- 
posed water  and  oil? 

23.  In  obedience  to  the  laws  here  hinted  at,  there  is  a  constant 
tendency  (Plate  IX.)  of  polar  waters  toward  the  tropics  and  of 
tropical  waters  toward  the  poles.  Captain  Wilkes,  of  the  United 
States  Exploring  Expedition,  crossed  one  of  these  hyperborean 
under-currents  two  hundred  miles  in  breadth  at  the  equator. 

24.  Assuming  the  maximum  velocity  of  the  Gulf  Stream  at 
five  knots,  and  its  depth  and  breadth  in  the  Narrows  of  Bernini 
as  before  (§  9),  the  vertical  section  across  would  present  an  area 
of  two  hundred  millions  of  square  feet  moving  at  the  rate  of 
seven  feet  three  inches  per  second— ^that  is,  sixteen  hundred  and 
fifty  million  cubic  feet  would  cross  this  section  in  a  second. 
Such  a  volume  of  water,  at  Gulf- Stream  temperature,  would  not 
be  as  heavy  by  fifteen  million  pounds  as  an  equal  volume,  equal- 
ly salt,  at  ocean  temperature.  If  these  estimated  dimensions  (as- 
sumed merely  for  the  purposes  of  illustration)  be  within  limits, 
then  the  force  per  second  operating  here  to  propel  the  waters  of 
the  Gulf  toward  the  pole  is  the  equilibrating  tendency  due  to  fif- 
teen millions  of  pounds  of  water  in  the  latitude  of  Bemini.  This 
is  in  one  scale  of  the  balance.  In  the  other,  the  polar  scale,  there 
is  the  difference  of  absolute  weight  due  an  equal  volume  of  water 
in  the  polar  basin,  on  account  of  its  degree  of  temperature  as  well 
as  of  saltness. 

25.  In  investigating  the  currents  of  the  seas,  such  agencies 
should  be  taken  into  account.  As  a  cause,  I  doubt  whether  this 
one  is  sufficient  of  itself  to  produce  a  stream  of  such  velocity  and 
compactness  as  that  of  the  Gulf;  for,  assuming  its  estimated  dis- 
charge to  be  correct,  the  proposition  is  almost  susceptible  of  math- 


THE  GULF  STREAM.  35 

ematical  demonstration,  that  to  overcome  the  resistance  opposed 
in  consequence  of  its  velocity  would  require  a  force  at  least  suffi- 
cient to  drive,  at  the  rate  of  three  miles  the  hour,  ninety  thousand 
millions  of  tons  up  an  inclined  plane  having  an  ascent  of  three 
inches  to  the  mile.*  Yet  heat,  the  very  principle  from  which  one 
of  these  agents  is  derived,  is  admitted  to  be  one  of  the  chief  causes 
of  those  winds  which  are  said  to  be  the  sole  cause  of  this  current. 

26.  The  chemical  properties,  or,  if  the  expression  be  admissible, 
the  galvanic  properties  of  the  Gulf  Stream  waters,  as  they  come 
from  their  fountains,  are  different,  or,  rather,  more  intense  than 
they  are  in  sea  water  generally.  If  so,  they  may  have  a  peculiar 
molecular  arrangement  or  viscosity  that  resists  the  admixture  of 
other  sea  waters  differing  in  temperature  and  saltness.  It  is  a 
well  known  fact,  that  waters  of  different  temperatures,  when  put 
in  the  same  vessel,  do  not  readily  mix  of  themselves,  but  require 
the  process  of  agitation.  Nor  do  large  volumes  of  water  in  mo- 
tion readily  admit  of  the  admixture  of  water  at  rest. 

In  1843  the  Secretary  of  the  Navy  took  measures  for  procur- 
ing a  series  of  observations  and  experiments  with  regard  to  the 
corrosive  effects  of  sea  water  upon  the  copper  sheathing  of  ships. 
With  patience,  care,  and  labor,  these  researches  were  carried  on 
for  a  period  of  ten  years ;  and  it  is  said  the  fact  has  been  estab- 
lished, that  the  copper  on  the  bottom  of  ships  cruising  in  the  Ca- 
ribbean Sea  and  Gulf  of  Mexico  suffers  more  from  the  action  of 
sea  water  upon  it  than  does  the  copper  of  ships  cruising  in  any 
other  part  of  the  ocean.  In  other  words,  the  salts  of  these  waters 
create  the  most  powerful  galvanic  battery  that  is  found  in  the 
ocean. 

27.  Nov/'  it  may  be  supposed — other  things  being  equal — that 
the  strength  of  this  galvanic  battery  in  the  sea  depends  in  some 
measure  upon  the  proportion  of  Salts  that  the  sea  waters  hold  in 
solution,  and  also  upon  temperature. 

28.  If,  therefore,  in  the  absence  of  better  information,  this  sug- 
gestion be  taken  as  a  probability  as  to  the  origin  of  these  galvanic 
properties,  we  may  go  a  step  farther,  and  draw  the  inference  that 
the  vraters  of  the  Gulf  Stream,  as  they  rush  out  in  such  volume 

*  Supposing  there  be  no  resistance  from  friction. 

c 


36  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

and  with  such  velocity  into  the  Atlantic,  have  not  only  chemical 
affinities  peculiar  to  themselves,  but,  having  more  salts,  higher  tem- 
perature, and  a  high  velocity,  they  are  not  so  permeable  to  water 
differing  from  them  in  all  these  respects,  and,  consequently,  the 
line  of  meeting  between  them  'and  the  other  water  of  the  ocean 
becomes  marked.  This  is  the  case  with  almost  all  waters  in  rapid 
motion.  Where  the  Mississippi  and  Missouri  rivers  come  togeth- 
er, there  is  a  similar  reluctance  on  the  part  of  their  waters  to  min- 
gle, for  the  line  of  meeting  between  them  can  be  traced  for  miles 
below  the  junction  of  the  two  rivers. 

29.  The  story  told  by  the  copper  (§  26)  and  the  blue  color  (§  3) 
indicates  a  higher  point  of  saturation  with  salts  than  sea  water 
generally,  and  the  salometer  confirms  it.  Dr.  Thomassy,  a  French 
savant,  who  has  been  extensively  engaged  in  the  manufacture  of 
salt  by  solar  evaporation,  informs  me  that  on  his  passage  to  the 
United  States  he  tried  the  saltness  of  the  water  with  a  most  del- 
icate instrument :  he  found  it  in  the  Bay  of  Biscay  to  contain  3J 
per  cent,  of  salt ;  in  the  trade-wind  region,  4^*^  per  cent. ;  and  in 
the  Gulf  Stream,  off  Charleston,  4  per  cent.,  notwithstanding  the 
Amazon  and  the  Mississippi,  with  all  the  intermediate  rivers,  and 
the  clouds  of  the  West  Indies,  had  lent  their  fresh  water  to  dilute 
the  saltness  of  this  basin. 

30.  Now  the  question  may  be  asked.  What  should  make  the 
waters  of  the  Mexican  Gulf  and  Caribbean  Sea  Salter  than  the 
waters  of  like  temperature  in  those  parts  of  the  ocean  through 
which  the  Gulf  Stream  flows  ? 

31.  There  are  physical  agents  that  are  known  to  be  at  work  in 
different  parts  of  the  ocean,  the  tendency  of  which  is  to  make  the 
waters  in  one  part  of  the  ocean  Salter  and  heavier,  and  in  another 
part  lighter  and  less  salt  than  the  average  of  sea  water.  These 
agents  are  those  employed  by  sea-shells  in  secreting  solid  matter 
for  their  structures ;  they  are  also  heat*  and  radiation,  evapora- 
tion and  precipitation. 

32.  In  the  trade- wind  regions  at  sea  (Plate  YIII.),  evaporation 
is  generally  in  excess  of  precipitation,  while  in  the  extra-tropical 
regions  the  reverse  is  the  case ;  that  is,  the  clouds  let  down  more 

*  According  to  Doctor  Marcet,  sea  water  contracts  down  to  28°. 


THE  GULF  STREAM. 


37 


water  there  than  the  winds  take  up  again ;  and  these  are  the  re- 
gions in  which  the  Gulf  Stream  enters  the  Atlantic. 

33.  Along  the  shores  of  India,  where  experiments  have  been 
carefully  made,  the  evaporation  from  the  sea  amounts  to  three 
fourths  of  an  inch  dailj.  Suppose  it  in  the  trade-wind  region  of 
the  Atlantic  to  amount  to  only  half  an  inch,  that  would  give  an 
annual  evaporation  of  fifteen  feet.  In  the  process  of  evaporation 
from  the  sea,  fresh  water  only  is  taken  up,  the  salts  are  left  behind. 

Xow  a  layer  of  sea  water  fifteen  feet  deep,  and  as  broad  as  the 
trade-wind  belts  of  the  Atlantic,  and  reaching  across  the  ocean, 
contains  an  immense  amount  of  salts. 

34.  The  great  equatorial  current  (Plate  VI.)  which  sweeps  from 
the  shores  of  Africa  across  the  Atlantic  into  the  Caribbean  Sea  is 
a  surface  current ;  and  may  it  not  bear  into  that  sea  a  large  por- 
tion of  those  waters  that  have  satisfied  the  thirsty  trade-winds 
with  saltless  vapor  ?  If  so — and  it  probably  does — have  we  not 
detected  here  the  foot-prints  of  an  agent  that  does  tend  to  make 
the  waters  of  the  Caribbean  Sea  Salter,  and  therefore  heavier  than 
the  average  of  sea  water  at  a  given  temperature  ? 

It  is  immaterial,  so  far  as  the  correctness  of  the  principle  upon 
which  this  reasoning  depends  is  concerned,  whether  the  annual 
evaporation  from  the  trade-wind  regions  of  the  Atlantic  be  fifteen, 
ten,  or  five  feet.  The  layer  of  water,  whatever  be  its  thickness, 
that  is  evaporated  from  this  part  of  the  ocean,  is  not  all  poured 
back  by  the  clouds  in  the  same  place  whence  it  came.  But  they 
take  it  and  pour  it  down  in  showers  upon  the  extra-tropical  regions 
of  the  earth — on  the  land  as  well  as  in  the  sea — and  on  the  land 
more  water  is  let  down  than  is  taken  wp  into  the  clouds  again. 
The  rest  sinks  down  through  the  soil  to  feed  the  springs,  and  re- 
turn through  the  rivers  to  the  sea.  Suppose  the  excess  of  precip- 
itation in  these  extra-tropical  regions  of  the  sea  to  amount  to  but 
twelve  inches,  or  even  to  but  two — it  is  twelve  inches  or  two  inch- 
es, as  the  case  may  be,  of  fresh  water  added  to  the  sea  in  those 
parts,  and  which  therefore  tends  to  lessen  the  specific  gravity  of 
sea  water  there  to  that  extent,  and  to  produce  a  double  effect,  for 
the  simple  reason  that  what  is  taken  from  one  scale,  by  being  put 
into  the  other,  doubles  the  difference. 


38        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

35.  Now  that  we  may  form  some  idea  as  to  the  influence  which 
the  salts  left  by  the  vapor  that  the  trade-winds,  northeast  and 
southeast,  take  up  from  sea  water,  is  calculated  to  exert  in  crea- 
ting currents,  let  us  make  a  partial  calculation  to  show  how  much 
salt  this  vapor  held  in  solution  before  it  was  taken  up,  and,  of 
course,  while  it  was  yet  in  the  state  of  sea  water.  The  northeast 
trade-wind  regions  of  the  Atlantic  embrace  an  area  of  at  least  three 
million  square  miles  ;  and  the  yearly  evaporation  from  it  is  (§  33), 
we  will  suppose,  fifteen  feet.  The  salt  that  is  contained  in  a  mass 
of  sea  water  covering  to  the  depth  of  fifteen  feet  an  area  of  three 
million  square  miles  in  superficial  extent,  would  be  sufficient  to 
cover  the  British  islands  to  the  depth  of  fourteen  feet.  As  this 
water  supplies  the  trade- winds  with  vapor,  it  therefore  becomes 
Salter,  and  as  it  becomes  Salter,  the  forces  of  aggregation  among 
its  particles  are  increased,  as  vre  may  infer  from  the  fact  (§  27), 
that  the  waters  of  the  Gulf  Stream  are  reluctant  to  mix  with  those 
of  the  ocean. 

36.  Whatever  be  the  cause  that  enables  these  trxade-wind  waters 
to  remain  on  the  surface,  whether  it  be  from  the  fact  just  stated, 
and  in  consequence  of  which  the  waters  of  the  Gulf  Stream  are 
held  together  in  their  channel ;  or  whether  it  be  from  the  fact  that 
the  expansion  from  the  heat  of  the  torrid  zone  is  sufficient  to  com- 
pensate for  this  increased  saltness  ;  or  whether  it  be  from  the  low 
temperature  and  high  saturation  of  the  submarine  waters  of  the  in- 
ter-tropical ocean ;  or  whether  it  be  owing  to  all  of  these  influences 
together  that  these  waters  are  kept  on  the  surface,  suffice  it  to  say, 
we  do  know  that  they  go  into  the  Caribbean  Sea  (§  34)  as  a  sur- 
face current.  On  their  passage  to  and  through  it,  they  intermin- 
gle with  the  fresh  waters  that  are  emptied  into  the  sea  from  the 
Amazon,  the  Oronoco,  and  the  Mississippi,  and  from  the  clouds, 
and  the  rivers  of  the  coasts  round  about.  An  immense  volume  of 
fresh  water  is  supplied  from  these  sources.  It  tends  to  make  tlie 
sea  water,  that  the  trade-winds  have  been  playing  upon  and  driv- 
ing along,  less  briny,  warmer,  and  lighter ;  for  the  waters  of  these 
large  inter-tropical  streams  are  warmer  than  sea  water.  This  ad- 
mixture of  fresh  water  still  leaves  the  Gulf  Stream  a  brine  stronger 
than  that  of  the  extra-tropical  sea  generally,  but  not  quite  so 
strong  as  that  of  tlie  trade-wind  regions  (§  29). 


THE  GULF  STREAM.  39 

It  is  safe  to  assume  that  the  trade-winds,  by  tlieir  constant  force, 
do  assist  to  skim  the  Athantic  of  the  water  that  has  supplied  them 
with  vapor,  driving  it  into  the  Caribbean  Sea,  whence,  for  causes 
unknown,  it  escapes  by  the  channel  of  the  Gulf  Stream  in  prefer- 
ence to  any  other.* 

37.  In  the  present  state  of  our  knowledge  concerning  this  won- 
derful phenomenon — for  the  Gulf  Stream  is  one  of  the  most  mar- 
velous things  in  the  ocean — we  can  do  little  more  than  conjecture. 
But  we  have  two  causes  in  operation  which  we  may  safely  assume 
are  among  those  concerned  in  producing  the  Gulf  Stream.  One 
of  these  is  in  the  increased  saltness  of  its  water  after  the  trade- 
winds  have  been  supplied  v*dth  vapor  from  it,  be  it  much  or  little  ; 
and  the  other  is  in  the  diminished  quantum  of  salt  which  the  Bal- 
tic and  the  JSTorthern  Seas  contain.  The  waters  of  the  Baltic  are 
nearly  fresh ;  they  are  said  to  contain  only  about  half  as  much 
salt  as  sea  water  does  generally. 

38.  ISTow  here  we  have,  on  one  side,  the  Caribbean  Sea  and 
Gulf  of  Mexico,  with  their  waters  of  brine  ;  on  the  other,  the  gTcat 
Polar  basin,  the  Baltic  and  the  North  Sea,  the  two  latter  with 
waters  that  are  but  little  more  than  brackish,  f  In  one  set  of 
these  sea-basins  the  water  is  heavy ;  in  the  other  it  is  light.  Be- 
tween them  the  ocean  intervenes  ;  but  water  is  bound  to  seek  and 
to  maintain  its  level ;  and  here,  therefore,  we  unmask  one  of  the 
agents  concerned  in  causing  the  Gulf  Stream.  What  is  the  in- 
fluence of  this  agent — that  is,  how  great  is  it,  and  to  what  extent 
does  it  go — we  can  not  say ;  only  it  is  at  least  one  of  the  agents 
concerned.  Moreover,  speculate  as  we  may  as  to  all  the  agencies 
concerned  in  collecting  these  waters,  that  have  supplied  the  trade- 
winds  with  vapor,  into  the  Caribbean  Sea,  and  then,  in  driving 
them  across  the  Atlantic — of  this  we  may  be  sure,  that  the  salt 
which  the  trade-wind  vapor  leav-es  behind  in  the  tropics  has  to  be 

*  The  fact  is  familiar  to  all  concerned  in  the  manufacture  of  salt  by  solar  evapora- 
tion, that  the  first  show  of  crystallization  commences  at  the  surface. 

t  The  Polar  basin  has  a  known  water  area  of  3,000,000  square  miles,  and  an  unex- 
plored area,  including  land  and  water,  of  1,500,000  square  miles.  Whether  the  water 
in  this  basin  be  more  or  less  salt  than  that  of  the  inter-tropical  seas,  we  know  it  is  quite 
different  in  temperature,  and  difference  of  temperature  will  beget  currents  quite  as 
readily  as  difference  in  saltness,  for  change  in  specific  gravity  follows  either. 


40  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

conveyed  away  from  the  trade-wind  region,  to  be  mixed  up  again 
in  due  proportion  with  the  other  water  of  the  sea — the  Baltic  Sea 
and  the  Arctic  Ocean  included — and  that  these  are  som.e  of  the 
waters,  at  least,  which  we  see  running  off  through  the  Gulf 
Stream.  To  convey  them  away  is  doubtless  one  of  the  offices 
which,  in  the  economy  of  the  ocean,  has  been  assigned  to  it. 

As  to  the  temperature  of  the  Gulf  Stream,  there  is,  in  a  winter's 
day,  off  Hatteras,  and  even  as  high  up  as  the  Grand  Banks  of  New- 
foundland in  mid  ocean,  a  difference  between  its  waters  and  those 
of  the  ocean  near  by  of  20°,  and  even  30°.  Water,  we  know,  ex- 
pands by  heat,  and  here  the  difference  of  temperature  may  more 
than  compensate  for  the  difference  in  saltness,  and  leave,  therefore, 
the  waters  of  the  Gulf  Stream  lighter  by  reason  of  their  warmth. 

39.  If  they  be  lighter,  they  should  therefore  occupy  a  higher 
level  than  those  tlu'ough  which  they  flow.  Assuming  the  depth 
off  Hatteras  to  be  one  hundred  and  fourteen  fathoms,  and  allow- 
ing the  usual  rates  of  expansion  for  sea  w^ater,  figures  show  that 
the  middle  or  axis  of  the  Gulf  Stream  there  should  be  nearly  two 
feet  higher  than  the  contiguous  waters  of  the  Atlantic.  Hence 
the  surface  of  the  stream  should  present  a  double  inclined  plane, 
from  which  the  water  would  be  running  down  on  either  side  as 
from  the  roof  of  a  house.  As  this  runs  off  at  the  top,  the  same 
weio-ht  of  colder  water  runs  in  at  the  bottom,  and  so  raises  up  the 
cold  water  bed  of  the  Gulf  Stream,  and  causes  it  to  become  shal- 
lower and  shallower  as  it  goes  north.  That  the  Gulf  Stream  is 
therefore  roof-shaped,  causing  the  waters  on  its  surface  to  flow  off 
to  cither  side  from  the  middle,  we  have  not  only  circumstantial 
evidence  to  show,  but  observations  to  prove. 

40.  Navigators,  while  drifting  along  with  the  Gulf  Stream,  have 
lowered  a  boat  to  try  the  surface  current.  In  such  cases,  the  boat 
would  drift  either  to  the  east  or  to  the  west,  as  it  happened  to  be 
on  one  side  or  the  other  of  the  axis  of  the  stream,  while  the  ves- 
sel herself  would  drift  along  with  the  stream  in  the  direction  of 
its  course ;  thus  showing  the  existence  of  a  shallow  roof-current 
from  the  middle  toward  either  edge,  Avhich  would  carry  the  boat 
along,  but  which,  being  superficial,  does  not  extend  deep  enough 
to  affect  the  drift  of  the  vessel. 


THE  GULF  STREAM.  41 

41.  That  sucli  is  the  case  (§  39)  is  also  indicated  by  the  circum- 
stance that  the  sea-weed  and  drift-wood  which  are  found  in  such 
large  quantities  along  the  outer  edge  (§  13)  of  the  Gulf  Stream,  are 
rarely,  even  with  the  prevalence  of  easterly  winds,  found  along  its 
inner  edge — and  for  the  simple  reason  that  to  cross  the  Gulf  Stream, 
and  to  pass  over  from  that  side  to  this,  they  would  have  to  drift 
up  an  inclined  plane,  as  it  were  ;  that  is,  they  would  have  to  stem 
this  roof-current  until  they  reached  the  middle  of  the  stream.  We 
rarely  hear  of  planks,  or  wrecks,  or  of  any  floating  substance  which 
is  cast  into  the  sea  on  the  other  side  of  the  Gulf  Stream  being 
found  alons:  the  coast  of  the  United  States.  Drift-wood,  trees, 
and  seeds  from  the  West  India  islands,  are  said  to  have  been  cast 
up  on  the  shores  of  Europe,  but  never,  that  I  ever  heard,  on  the 
Atlantic  shores  of  this  country. 

We  are  treating  now  of  the  effects  of  physical  causes.  The 
question  to  which  I  ask  attention  is,  AVhy  does  the  Gulf  Stream 
slough  off  and  cast  upon  its  outer  edge,  sea-weed,  drift-wood,  and 
all  other  solid  bodies  that  are  found  floating  upon  it  ? 

42.  One  cause  has  been  shown  to  be  in  its  roof-shaped  current ; 
but  there  is  another  which  tends  to  produce  the  same  effect ;  and 
because  it  is  a  physical  agent,  it  should  not,  in  a  treatise  of  this 
kind,  be  overlooked,  be  its  action  never  so  slight.  I  allude  norv 
to  the  effects  produced  upon  the  drift  matter  of  the  stream  by  the 
diurnal  rotation  of  the  earth. 

43.  Take,  for  illustration,  a  railroad  that  runs  north  and  south. 
It  is  well  known  to  engineers  that  when  the  ears  are  going  north 
on  such  a  road,  their  tendency  is  to  run  off  on  the  east  side ;  but 
when  the  train  is  going  south,  their  tendency  is  to  run  off  on  the 
west  side  of  the  track — i.  e.,  always  on  the  right-hand  side  in  our 
hemisphere.  Whether  the  road  be  one  mile  or  one  hundred  miles 
in  length,  the  effect  of  diurnal  rotation  is  the  same,  and  the  tend- 
ency to  run  off,  as  you  cross  a  given  parallel  at  a  stated  rate  of 
speed,  is  the  same ;  whether  the  road  be  long  or  short,  the  tend- 
ency to  fly  off  the  track  being  in  proportion  to  the  speed  of  the 

.  trains,  and  not  at  all  in  proportion  to  the  length  of  the  road. 
44.  ]^ow,  vis  inerticB  and  velocity  being  taken  into  the  account, 
the  tendency  to  obey  the  force  of  this  diurnal  rotation,  and  to  trend 


42  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

to  the  riglit,  is  proportionably  as  great  in  the  case  of  a  patch  of 
sea-weed  as  it  drifts  along  the  Gulf  Stream,  as  it  is  in  the  case  of 
the  train  of  cars  as  they  speed  to  the  north  along  the  iron  track  of 
the  Hudson  Eiver  railway,  or  any  other  railway  that  lies  north 
and  south.  The  rails  restrain  'the  cars  and  prevent  them  from 
flyino-  off;  but  there  are  no  rails  to  restrain  the  sea-weed,  and 
nothing  to  prevent  the  drift-matter  of  the  Gulf  Stream  from  going 
off  in  obedience  to  this  force.  The  slightest  impulse  tending  to 
turn  aside  bodies  moving  freely  in  water  is  immediately  felt  and 
implicitly  obeyed. 

45.  It  is  in  consequence  of  this  diurnal  rotation  that  drift-wood 
coming  down  the  Mississippi  is  so  very  apt  to  be  cast  upon  the 
west  or  right  bank.  This  is  the  reverse  of  what  obtains  upon  the 
Gulf  Stream,  for  it  flows  to  the  north ;  it  therefore  sloughs  off 
(§  43)  to  the  east.  i 

The  effect  of  diurnal  rotation  upon  the  winds  and  upon  the  cur- 
rents of  the  sea  is  admitted  by  all — the  trade-winds  derive  their 
easting  from  it — it  must,  therefore,  extend  to  all  the  mlitter  which 
these  currents  bear  with  them,  to  the  largest  iceberg  as  well  as 
to  the  merest  spire  of  grass  that  floats  upon  the  waters,  or  the 
minutest  organism  that  the  most  j)Owerful  microscope  can  detect 
among  the  impalpable  particles  of  sea-dust.  This  effect  of  diur- 
nal rotation  upon  drift  will  be  frequently  alluded  to  in  the  pages 
of  this  work. 

46.  In  its  course  to  the  north,  the  Gulf  Stream  gradually  trends 
more  and  more  to  the  eastward,  until  it  arrives  off  the  Banks  of 
Newfoundland,  where  its  course  becomes  nearly  due  east.  These 
banks,  it  has  been  thought,  deflect  it  from  its  proper  course,  and 
cause  it  to  take  this  turn.  Examination  will  prove,  I  think,  that 
they  are  an  effect,  certainly  not  the  cause.  It  is  here  that  the 
frigid  current  already  spoken  of  (§  11),  with  its  icebergs  from  the 
north,  are  met  and  melted  by  the  warm  waters  of  the  Gulf.  Of 
course  the  loads  of  earth,  stones,  and  gravel  brought  down  upon 
them  are  here  deposited.  Captain  Scoresby,  far  away  in  the  north, 
counted  five  hundred  icebergs  setting  out  from  the  same  vicinity 
upon  this  cold  current  for  the  south.  Many  of  them,  loaded  with 
earth,  have  been  seen  aground  on  the  Banks,     This  process  of 


THE  GULF  STREAM.  43 

transfernng  deposits  from  the  north  for  these  shoals,  and  of  snow- 
ing down  upon  them  the  infusoria  and  the  corpses  of  "livino' 
creatures"  that  are  spawned  so  abundantly  in  the  warm  waters  of 
the  Gulf  Stream,  and  sloughed  off  in  myriads  for  burial  where  the 
conflict  between  it  and  the  great  Polar  current  (§  14)  takes  place, 
is  everlastingly  going  on.  These  agencies,  with  time,  seem  alto- 
gether adequate  to  the  formation  of  extensive  bars  or  banks. 

The  deep  sea  soundings  that  have  been  made  by  vessels  of  the 
navy  (Plate  XL)  tend  to  confirm  this  view  as  to  the  formation  of 
these  Banks.  The  greatest  contrast  in  the  bottom  of  the  Atlantic 
is  just  to  the  south  of  these  Banks.  Nowhere  in  the  open  sea  has 
the  water  been  found  to  deepen  so  suddenly  as  here.  Coming 
from  the  north,  the  bottom  of  the  sea  is  shelving ;  but  suddenly, 
after  passing  these  Banks,  its  depth  increases  by  almost  a  precip- 
itous descent  for  many  thousand  feet,  thus  indicating  that  the  de- 
bris which  forms  the  Grand  Banks  comes  from  the  north. 

47.  From  the  Straits  of  Bemini  the  course  of  the  Gulf  Stream 
(Plate  YI.)  describes  (as  far  as  it  can  be  traced  over  toward  the 
British  Islands  which  are  in  the  midst  of  its  waters)  the  arc  of  a 
great  circle  as  nearly  as  may  be.  Such  a  course  as  the  Gulf 
Stream  takes  is  very  nearly  the  course  that  a  cannon  ball,  could 
it  be  shot  from  these  straits  to  those  islands,  would  describe. 

If  it  were  possible  to  see  Ireland  from  Bemini,  and  to  get  a  can- 
non that  would  reach  that  far,  the  person  standing  on  Bemini  and 
taking  aim,  intending  to  shoot  at  Ireland  as  a  target,  would,  if  the 
earth  were  at  rest,  sight  direct,  and  make  no  allowance  for  differ- 
ence of  motion  between  marksman  and  target. 

48.  But  there  is  diurnal  rotation  ;  the  earth  does  revolve  on  its 
axis ;  and  since  Bemini  is  nearer  to  the  equator  than  Ireland  is, 
the  gun  would  be  moving  in  diurnal  rotation  (§  16)  faster  than  the 
target,  and  therefore  the  marksman,  taking  aim  point  blank  at  his 
target,  would  miss.  He  would  find,  on  examination,  that  he  had 
shot  south — that  is,  to  the  right  (§  43)  of  his  mark.  In  other 
words,  that  the  path  actually  described  by  the  ball  would  be  the 
resultant  of  this  difference  in  the  rate  of  rotation  and  the  traject- 
ile  force ;  the  former,  impelling  to  the  east,  would  cause  the  ball 
to  describe  a  great  circle,  but  one  witli  too  much  obliquity  to  pass 


44  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

througli  the  target.     Like  a  raj  of  light  from  the  stars,  the  ball 
would  be  affected  by  aberration. 

49.  It  is  the  case  of  the  passenger  in  the  railroad  car  throwing 
an  apple,  as  the  train  sweeps  by,  to  a  boy  standing  by  the  way- 
side. If  he  tlu'ow  straight  at'  the  boy,  he  will  miss,  for  the  apple, 
partaking  of  the  motion  of  the  cars,  will  go  ahead  of  the  boy,  and 
for  the  very  reason  that  the  shot  will  pass  in  advance  of  the  tar- 
get, for  both  the  marksman  and  the  passenger  are  going  faster 
than  the  object  at  which  they  aim. 

50.  Hence  we  may  assume  it  as  a  law,  that  the  natural  tenden- 
cy of  all  currents  in  the  sea,  like  the  natural  tendency  of  all  pro- 
jectiles through  the  air,  is  to  describe  their  curves  of  flight  in  the 
planes  of  great  circles.  The  natural  tendency  of  all  matter,  when 
put  in  motion,  is  to  go  from  point  to  point  by  the  shortest  dis- 
tance, and  it  requires  force  to  overcome  this  tendency.  Light, 
heat,  and  electricity,  running  water,  and  all  substances,  whether 
ponderable  or  imponderable,  seek,  when  in  motion,  to  obey  this 
law.  Electricity  may  be  turned  aside  from  its  course,  and  so 
may  the  cannon  ball  or  running  water ;  but  remove  every  obstruc- 
tion, and  leave  the  current  or  the  shot  free  to  continue  on  in  the 
direction  of  the  first  impulse,  or  to  turn  aside  of  its  own  volition, 
so  to  speak,  and  straight  it  wiU  go,  and  continue  to  go — if  on  a 
plane,  in  a  straight  line ;  if  on  a  sphere,  in  the  arc  of  a  great  cir- 
cle— thus  showing  that  it  has  no  volition  except  to  obey  impulse, 
and  the  physical  requirements  to  take  the  shortest  way  to  its  point 
of  destination. 

51.  The  waters  of  the  Gulf  Stream,  as  they  escape  from  the 
Gulf  (§  37),  are  bound  for  the  British  Islands,  to  the  North  Sea, 
and  Frozen  Ocean  (Plate  IX.).  Accordingly,  they  take  (§  47),  in 
obedience  to  this  pliysical  law,  the  most  direct  course  by  which 
nature  will  permit  them  to  reach  their  destination.  And  this 
course,  as  already  remarked,  is  nearly  that  of  the  great  circle,  and 
exactly  that  of  the  supposed  cannon  ball. 

52.  Many  philosophers  have  expressed  the  opinion — indeed,  the 
belief  (§  46)  is  common  among  mariners — that  the  coasts  of  the 
United  States  and  the  Shoals  of  Nantucket  turn  the  Gulf  Stream 
toward  tlie  east ;  but  if  the  view  I  have  been  endeavoring  to  make 


THE  GULF  STREAM.  45 

clear  be  correct — and  I  think  it  is — it  appears  that  the  course  of 
the  Gulf  Stream  is  fixed  and  prescribed  by  exactly  the  same  laws 
that  require  the  planets  to  revolve  in  orbits,  the  planes  of  which 
shall  pass  through  the  centre  of  the  sun  ;  and  that,  were  the  Nan- 
tucket Shoals  not  in  existence,  the  course  of  the  Gulf  Stream,  in 
the  main,  would  be  exactly  as  it  is  and  where  it  is.  The  Gulf 
Stream  is  bound  over  to  the  North  Sea  and  Bay  of  Biscay  partly 
for  the  reason,  perhaps,  that  the  waters  there  are  lighter  than 
those  of  the  Mexican  Gulf  (§  37) ;  and  if  the  Shoals  of  Nantucket 
w*ere  not  in  existence,  it  could  not  pursue  a  more  direct  route. 
The  Grand  Banks,  however,  are  encroaching  (§  46),  and  cold  cur- 
rents from  the  north  come  down  upon  it :  they  may,  and  probably 
do,  assist  now  and  then  to  turn  it  aside. 

53.  Now  if  this  explanation  as  to  the  course  of  the  Gulf  Stream 
and  its  eastward  tendency  hold  good,  a  current  setting  from  the 
north  toward  the  south  should  (§  21)  have  a  westward  tendency. 
It  should  also  move  in  a  circle  of  trajection,  or  such  as  would  be 
described  by  a  trajectile  moving  through  the  air  without  resistance 
and  for  a  great  distance.  Accordingly,  and  in  obedience  to  the 
propelling  powers,  derived  from  the  rate  at  which  different  paral- 
lels are  whirled  around  in  diurnal  motion  (§  16),  we  find  the  cur- 
rent from  the  north,  which  meets  the  Gulf  Stream  on  the  Grand 
Banks  (Plate  IX.),  taking  a  ^ovLihicestiuardly  direction,  as  already 
described  (§  45).  It  runs  down  to  the  tro]Dics  by  the  side  of  the 
Gulf  Stream,  and  stretches  as  far  to  the  west  as  our  own  shores 
will  allow.  Yet,  in  the  face  of  these  facts,  and  in  spite  of  this 
force,  both  Major  Rennell  and  M.  Arago  make  the  coasts  of  the 
United  States  and  the  Shoals  of  Nantucket  to  turn  the  Gulf 
Stream  toward  the  east. 

54.  But  there  are  other  forces  operating  upon  the  Gulf  Stream. 
They  are  derived  from  the  efiect  -of  changes  in  the  waters  of  the 
whole  ocean,  as  produced  by  changes  in  their  temperature  from 
time  to  time.  As  the  Gulf  Stream  leaves  the  coasts  of  the  United 
States,  it  begins  to  vary  its  position  according  to  the  seasons ;  the 
limit  of  its  northern  edge,  as  it  passes  the  meridian  of  Cape  Race 
(Plate  VL),  being  in  winter  about  latitude  40-41°,  and  in  Sep- 
tember, when  the  sea  is  hottest,  about  latitude  45-46°.      The 


46  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

trough  of  the  Gulf  Stream,  therefore,  may  be  supposed  to  waver 
about  in  the  ocean  not  unHke  a  pennon  in  the  breeze.  Its  head 
is  confined  between  the  shoals  of  the  Bahamas  and  the  Carolinas ; 
but  that  part  of  it  which  stretches  over  toward  the  Grand  Banks 
of  Newfoundland  is,  as  the  teitiperature  of  the  waters  of  the  ocean 
changes,  first  pressed  down  toward  the  south,  and  then  again  up 
toward  the  north,  according  to  the  season  of  the  year. 

55.  To  appreciate  the  extent  of  the  force  by  which  it  is  so  press- 
ed, let  us  imagine  the  waters  of  the  Gulf  Stream  to  extend  all  the 
way  to  the  bottom  of  the  sea,  so  as  completely  to  separate,  by  an 
impenetrable  liquid  wall,  if  you  please,  the  waters  of  the  ocean  on 
the  rio'lit  from  the  waters  in  the  ocean  on  the  left  of  the  stream. 

o 

It  is  the  heisrht  of  summer  :  the  waters  of  the  sea  on  either  hand 
are  for  the  most  part  in  a  liquid  state,  and  the  Gulf  Stream,  let  it 
be  supposed,  has  assumed  a  normal  condition  between  the  two  di- 
visions, adjusting  itself  to  the  pressure  on  either  side  so  as  to  bal- 
ance them  exactly  and  be  in  equilibrium.  Now,  again,  it  is  the 
dead  of  winter,  and  the  temperature  of  tlie  waters  over  an  area  of 
millions  of  square  miles  in  the  North  Atlantic  has  been  changed 
many  degrees,  and  this  change  of  temperature  has  been  followed 
likewise  by  a  change  in  volume  of  those  waters,  amounting,  no 
doubt,  in  the  aggregate,  to  many  hundred  millions  of  tons,  over 
the  whole  ocean ;  for  sea  water,  unlike  fresh  (§  31),  contracts  to 
freezing.  Now  is  it  probable  that,  in  passing  from  their  summer 
to  their  winter  temperature,  the  sea  waters  to  the  right  of  the  Gulf 
Stream  should  change  their  specific  gravity  exactly  as  much  in 
the  aggregate  as  do  the  waters  in  the  whole  ocean  to  the  left  of 
it  ?  If  not,  the  difference  must  be  compensated  by  some  means. 
Sparks  are  not  more  prone  to  fly  upward,  nor  water  to  seek  its 
level,  than  Nature  is  sure  with  her  efforts  to  restore  equilibrium 
in  both  sea  and  air  whenever,  wherever,  and  by  whatever  it  be 
disturbed.  Therefore,  thougli  the  waters  of  the  Gulf  Stream  do 
not  extend  to  the  bottom,  and  though  they  be  not  impenetrable 
to  the  waters  on  either  hand,  yet,  seeing  that  they  have  a  waste 
of  waters  on  the  right  and  a  waste  of  waters  on  the  left,  to  which 
(§  2)  they  offer  a  sort  of  resisting  permeability,  we  are  enabled  to 
comprehend  how  the  waters  on  either  hand,  as  their  specific  grav- 


THE  GULF  STREAM.  47 

ity  is  increased  or  diminished,  will  impart  to  the  trough  of  this 
stream  a  vibratory  motion,  pressing  it  now  to  the  right,  now  to  the 
left,  according  to  the  seasons  and  the  consequent  changes  of  tem- 
perature in  the  sea. 

56.  Plate  YI.  shows  the  limits  of  the  Gulf  Stream  for  March 
and  September.  The  reason  for  this  change  of  position  is  obvi- 
ous. The  banks  of  the  Gulf  Stream  (§1)  are  cold  w^ater.  In 
winter,  the  volume  of  cold  water  on  the  American,  or  left  side  of 
the  stream,  is  greatly  increased.  It  must  have  room,  and  gains 
it  bj  pressing  the  warmer  waters  of  the  stream  farther  to  the  south, 
or  right.  In  September,  the  temperature  of  these  cold  waters  is 
modified  ;  there  is  not  such  an  extent  of  them,  and  then  the  w^arm- 
er  waters,  in  turn,  press  them  back,  and  so  the  pendulum-like  mo- 
tion is  preserved. 

57.  The  observations  made  by  the  United  States  Coast  Survey 
indicate  that  there  are  in  the  Gulf  Stream  threads  of  warmer,  sep- 
arated by  streaks  of  cooler  water.  See  Plate  VI.,  in  which  these 
are  shown ;  they  are  marked  x,  y,  z.  Figure  A  may  be  taken  to 
represent  a  thermometrical  cross  section  of  the  stream  opposite  the 
Capes  of  Virginia,  for  instance ;  the  top  of  the  curve  representing 
the  thermometer  in  the  threads  of  the  warmer  water,  and  the  de- 
pressions the  height  of  the  same  instrument  in  the  streaks  of  cool- 
er water  between,  thus  exhibiting,  as  one  sails  from  America  across 
the  Gulf  Stream,  a  remarkable  series  of  thermometrical  elevations 
and  depressions  in  the  surface  temperature  of  this  mighty  river  in 
the  sea. 

,  58.  These  streaks,  0:^  y,  ,c,  are  not  found  in  the  Gulf  Stream  as 
it  issues  from  its  fountain,  and  I  have  thought  them  to  be  an  in- 
cident of  the  process  by  which  the  waters  of  the  Stream  gradually 
grow  cool.  Suppose  a  perfect  calm  over  this  stream,  and  that  all 
the  water  on  the  top  of  it  to  the  depth  of  ten  feet  were  suddenly, 
as  it  runs  along  in  a  winter's  day,  to  be  stricken  by  the  wand 
of  some  magician,  and  reduced  from  the  temperature  of  75°  to 
that  of  32°,  the  water  below  the  depth  of  ten  feet  remaining  at 
75°  as  before.  How  would  this  cold  and  heavy  water  sink  ?  Like 
a  great  water-tight  floor  or  field  of  ice  as  broad  as  the  Gulf  Stream, 
and  loaded  to  sinking  ?     And  how  would  the  warm  water  rise  to 


48        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

the  top  ?  By  running  out  under  this  floor  or  field,  rising  up  over 
the  edges,  and  flowing  back  to  the  middle  ?  I  think  not ;  on  the 
contrary,  I  suppose  the  warm  water  would  rise  up  here  and  there 
in  streaks,  and  that  the  cold  w^ould  go  down  in  streaks  or  seams. 
The  process  would  be  not  unlike  what  we  see  going  on  in  a  fount- 
ain which  is  fed  by  one  or  more  bubbling  springs  from  below. 
We  can  see  the  warm  water  rising  up  in  a  column  from  the  ori- 
fice below,  and  in  winter  the  water  on  the  top  first  grows  cool  and 
then  sinks.  Now  imagine  the  fountain  to  be  a  long  and  narrow 
stream,  and  this  orifice  to  be  a  fissure  running  along  at  the  bottom 
in  the  middle  of  it,  and  feeding  it  with  warm  water.  We  can  well 
imagine  that  there  would  be  a  seam  of  water  rising  up  all  the  way 
in  the  middle  of  the  stream,  and  that  a  delicate  thermometer  would, 
in  cold  weather,  show  a  marked  difierence  of  temperature  between 
the  water  as  it  rises  up  in  this  seam,  and  that  going  down  on  either 
side  after  it  has  been  cooled.  Now  if  we  make  our  imaginary 
stream  broader,  and  place  at  a  little  distance  another  fissure  par- 
allel with  the  first,  and  also  supplying  warm  water,  there  would 
be  between  the  two  a  streak  of  cooler  water  descending  after  hav- 
ing parted  with  a  certain  degree  of  heat  at  the  surface,  and  thus 
we  would  have  repeated  the  ribbons  of  cold  and  warm  water  which 
the  Coast  Survey  has  found  in  the  Gulf  Stream. 

59.  The  hottest  water  in  the  Gulf  Stream  is  also  the  lightest ; 
as  it  rises  to  the  top,  it  is  cooled  both  by  evaporation  and  expo- 
sure, when  the  surface  is  replenished  by  fresh  supplies  of,  hot  wa- 
ter from  below.  Thus,  in  a  winter's  day,  the  waters  at  the  sur- 
face of  the  Gulf  Stream  off  Cape  Hatteras  may  be  at  80°,  and  at 
the  depth  of  five  hundred  fathoms — three  thousand  feet — as  act- 
ual observations  show,  the  thermometer  will  stand  at  57°.  Fol- 
lowing the  stream  thence  off  the  Capes  of  Virginia,  one  hundred 
and  twenty  miles,  it  will  be  found — the  water-thermometer  having 
been  carefully  noted  all  the  way — that  it  now  stands  a  degree  or 
two  less  at  the  surface,  while  all  below  is  cooler.  In  other  words, 
the  stratum  of  water  at  57°,  which  was  three  thousand  feet  below 
the  surface  off  Hatteras,  has,  in  a  course  of  one  hundred  and  twen- 
ty or  one  hundred  and  thirty  miles  in  a  horizontal  direction,  as- 


THE  GULF  STREAM. 


49 


cended,  vertically,  six  liiindred  feet ;  that  is,  this  stratum  has  run 
up  hill  with  an  ascent  of  five  or  six  feet  to  the  mile. 

60.  As  a  rule,  the  hottest  water  of  the  Gulf  Stream  is  at  or 
near  the  surface ;  and  as  the  deep-sea  thermometer  is  sent  down, 
it  shows  that  these  waters,  though  still  far  warmer  than  the  water 
on  either  side  at  corresponding  depths,  gradually  become  less  and 
less  warm  until  the  bottom  of  the  current  is  reached.  There  is 
reason  to  believe  that  the  warm  waters  of  the  Gulf  Stream  are  no- 
where permitted,  in  the  oceanic  economy,  to  touch  the  bottom  of 
the  sea.  There  is  every  where  a  cushion  of  cool  water  between 
them  and  the  solid  parts  of  the  earth's  crust.  This  arrangement 
is  suggestive,  and  strikingly  beautiful.  One  of  the  benign  offices 
of  the  Gulf  Stream  is  to  convey  heat  from  the  Gulf  of  ^Mexico, 
where  otherwise  it  would  become  excessive,  and  to  dispense  it  in 
regions  beyond  the  Atlantic  for  the  amelioration  of  the  climates 
of  the  British  Islands  and  of  all  Western  Europe.  Xow  cold  wa- 
ter is  one  of  the  best  non-conductors  of  heat,  and  if  the  warm  wa- 
ter of  the  Gulf  Stream  was  sent  across  the  Atlantic  in  contact 
with  the  solid  crust  of  the  earth — comparatively  a  good  conductor 
of  heat — instead  of  being  sent  across,  as  it  is,  in  contact  with  a 
cold,  non-conducting  cushion  of  cool  water  to  fend  it  from  the 
bottom,  all  its  heat  would  be  lost  in  the  first  part  of  the  way,  and 
the  soft  climates  of  both  France  and  England,  would  be  as  that  of 
Labrador,  severe  in  the  extreme,  and  ice-bound. 


50  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  11. 

INFLUENCE   OF  THE   GULP   STEEAM  UPON   CLIMATES. 

How  the  Climate  of  England  is  regulated  by  it,  ^  61. — Isothermal  Lines  of  the  At- 
lantic, 65. — Deep-sea  Temperatures  under  the  Gulf  Stream,  68. — Currents  indi- 
cated by  the  Fish,  70. — Sea-nettles,  73. — Climates  of  the  Sea,  75. — Offices  of  the 
Sea,  76. — Influence  of  the  Gulf  Stream  upon  the  Meteorology  of  the  Ocean,  78. — 
Furious  Storms,  80. — Dampness  of  the  English  Climate  due  the  Gulf  Stream,  83. 
^Its  Influence  upon  Storms,  85. — Wreck  of  the  Steamer  San  Francisco,  88. — 
Influence  of  the  Gulf  Stream  upon  Commerce  and  Navigation,  96. — Used  for  find- 
ing Longitude,  103. — Commerce  in  1769,  106. 

61.  MoDEEN  ingenuity  lias  suggested  a  beautiful  mode  of  warm- 
ing houses  in  winter.  It  is  done  by  means  of  hot  water.  The 
furnace  and  the  caldron  are  sometimes  placed  at  a  distance  from 
the  apartments  to  be  warmed.  It  is  so  at  the  Observatory.  In 
this  case,  pipes  are  used  to  conduct  the  heated  water  from  the 
caldron  under  the  superintendent's  dwelling  over  into  one  of  the 
basement  rooms  of  the  Observatory,  a  distance  of  one  hundred 
feet.  These  pipes  are  then  flared  out  so  as  to  present  a  large  cool- 
ing surface ;  after  which  they  are  united  into  one  again,  through 
which  the  water,  being  now  cooled,  returns  of  its  own  accord  to 
the  caldron.  Thus  cool  water  is  returning  all  the  time  and  flow- 
ing in  at  the  bottom  of  the  caldron,  while  hot  water  is  continually 
flowing  out  at  the  top. 

The  ventilation  of  the  Observatory  is  so  arranged  that  the  cir- 
culation of  the  atmosphere  through  it  is  led  from  this  basement 
room,  where  the  pipes  are,  to  all  other  parts  of  the  building ;  and 
in  the  process  of  this  circulation,  the  warmth  conveyed  by  the 
water  to  the  basement  is  taken  thence  by  the  air  and  distributed 
over  all  the  rooms.  Now,  to  compare  small  tilings  with  great,  we 
have,  in  the  warm  waters  whicli  are  confined  in  the  Gulf  of  ]\Iex- 
ico,  just  such  a  heating  apparatus  for  Great  Britain,  tlie  North 
Atlantic,  and  Western  Europe. 

62.  The  furnace  is  the  torrid  zone  ;  the  Mexican  Gulf  and  Ca- 


INFLUENCE  OF  THE  GULF  STREAM  UPON  CLIMATES.  51 

ribbean  Scta  are  the  caldrons  ;  the  Gulf  Stream  is  the  conducting 
pipe.  From  the  Grand  Banks  of  Newfoundland  to  the  shores  of 
Europe  is  the  basement — the  hot-air  chamber — in  which  this  pipe 
is  flared  out  so  as  to  present  a  large  cooling  surface.  Here  the 
circulation  of  the  atmosphere  is  arranged  by  nature  ;  and  it  is  such 
that  the  warmth  thus  conveyed  into  this  warm-air  chamber  of 
mid-ocean  is  taken  up  by  the  genial  west  winds,  and  dispensed,  in 
the  most  benign  manner,  throughout  Great  Britain  and  the  west 
of  Europe. 

63.  The  maximum  temperature  of  the  water-heated  air-cham- 
ber of  the  Observatory  is  about  90°.  The  maximum  temperature 
of  the  Gulf  Stream  is  86°,  or  about  9°  above  the  ocean  tempera- 
ture due  the  latitude.  Increasing  its  latitude  10°,  it  loses  but  2° 
of  temperature ;  and,  after  having  run  three  thousand  miles  to- 
ward the  north,  it  still  preserves,  even  in  winter,  the  heat  of  sum- 
mer. With  this  temperature,  it  crosses  the  40th  degree  of  north 
latitude,  and  there,  overflowing  its  liquid  banks,  it  spreads  itself 
out  for  thousands  of  square  leagues  over  the  cold  waters  around, 
and  covers  the  ocean  with  a  mantle  of  warmth  that  serves  so  much 
to  mitigate  in  Europe  the  rigors  of  winter.  Moving  now  more 
slowly,  but  dispensing  its  genial  influences  more  freely,  it  finally 
meets  the  British  Islands.  By  these  it  is  divided  (Plate  IX.), 
one  part  going  into  the  polar  basin  of  Spitzbergen,  the  other  en- 
tering the  Bay  of  Biscay,  but  each  with  a  warmth  considerably 
above  the  ocean  temperature.  Such  an  immense  volume  of  heated 
water  can  not  fail  to  carry  with  it  beyond  the  seas  a  mild  and  moist 
atmosphere.     And  this  it  is  which  so  much  softens  climate  there. 

64.  We  know  not,  except  approximately  in  one  or  two  places, 
what  the  depth  or  the  under  temperature  of  tlie  Gulf  Stream  may 
be ;  but  assuming  the  temperature  and  velocity  at  the  depth  of 
two  hundred  fathoms  to  be  those-  of  the  surface,  and  taking  the 
well-known  diflerence  between  the  capacity  of  air  and  of  water  for 
specific  heat  as  the  argument,  a  simple  calculation  will  show  that 
the  quantity  of  heat  discharged  over  the  Atlantic  from  the  waters 
of  the  Gulf  Stream  in  a  winter's  day  would  be  suflicient  to  raise 
the  whole  column  of  atmosphere  that  rests  upon  France  and  the 
British  Islands  from  the  freezing  point  to  summer  heat. 

D 


52  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

Every  west  wind  that  blows  crosses  the  stream  on  its  way  to 
Europe,  and  carries  with  it  a  portion  of  this  heat  to  temper  there 
the  northern  winds  of  winter.  It  is  the  influence  of  this  stream 
upon  climate  that  makes  Erin  the  "Emerald  Isle  of  the  Sea,"  and 
that  clothes  the  shores  of  Albion  in  evergreen  robes;  while  in  the 
same  latitude,  on  this  side,  the  coasts  of  Labrador  are  fast  bound 
in  fetters  of  ice.  In  a  valuable  paper  on  currents,*  jMr.  Eedfield 
states,  that  in  1831  the  harbor  of  St.  John's,  Newfoundland,  was 
closed  with  ice  as  late  as  the  month  of  June  ;  yet  who  ever  heard 
of  the  port  of  Liverpool,  on  the  other  side,  though  2°  farther  north, 
being  closed  with  ice,  even  in  the  dead  of  winter  ? 

65.  The  Thermal  Chart  (Plate  IV.)  shows  this.  The  isother- 
mal lines  of  60°,  50°,  &c.,  starting  off  from  the  parallel  of  40° 
near  the  coasts  of  the  United  States,  run  off  in  a  northeastwardly 
direction,  sho^nng  the  same  oceanic  temperature  on  the  European 
side  of  the  Atlantic  in  latitude  55°  or  60°,  that  we  have  on  the 
western  side  in  latitude  40°.  Scott,  in  one  of  his  beautiful  novels, 
tells  us  that  the  ponds  in  the  Orkneys  (latitude  near  60°)  are  not 
frozen  in  winter.  The  people  there  owe  their  soft  climate  to  this 
grand  heating  apparatus,  for  drift-wood  from  the  West  Indies  is 
occasionally  cast  ashore  there  by  the  Gulf  Stream. 

66.  'Nov  do  the  benefic-ial  influences  of  this  stream  upon  climate 
end  here.  The  West  Indian  Archipelago  is  encompassed  on  one 
side  by  its  chain  of  islands,  and  on  the  other  by  the  Cordilleras 
of  the  Andes,  contracting  with  the  Isthmus  of  Darien,  and  stretch- 
ing themselves  out  over  the  plains  of  Central  America  and  Mexi- 
co. Beginning  on  the  summit  of  this  range,  we  leave  the  regions 
of  pei^petual  snow,  and  descend  first  into  the  tierra  temj)lada,  and 
then  into  the  tierra  caliente,  or  burning  land.  Descending  still 
lower,  we  reach  both  the  level  and  the  surfoce  of  the  Mexican  seas, 
where,  were  it  not  for  this  beautiful  and  benign  system  of  aqueous 
circulation,  the  peculiar  features  of  the  suiTOunding  country  assure 
us  we  should  have  the  hottest,  if  not  the  most  pestilential  climate 
in  the  world.  As  the  waters  in  these  two  caldrons  become  heat- 
ed, they  are  borne  off  by  the  Gulf  Stream,  and  are  replaced  by 
cooler  currents  through  the  Caribbean  Sea ;  the  surface  water,  as 

*  American  Journal  of  Science,  vol.  xiv.,  p.  293. 


INFLUENCE  OF  THE  GULF  STREAM  UPON  CLIMATES.    53 

it  enters  here,  being  3°  or  4°,  and  that  in  depth  40°*  cooler  than 
when  it  escapes  from  the  Gulf.  Taking  only  this  difference  in 
surface  temperature  as  an  index  of  the  heat  accumulated  there,  a 
simple  calculation  will  show  that  the  quantity  of  heat  daily  car- 
ried off  by  the  Gulf  Stream  from  those  regions,  and  discharged 
over  the  Atlantic,  is  sufficient  to  raise  mountains  of  iron  from  zero 
to  the  melting  point,  and  to  keep  in  flow  from  them  a  molten 
stream  of  metal  greater  in  volume  than  the  waters  daily  discharged 
from  the  Mississippi  River.  Who,  therefore,  can  calculate  the  be- 
nign influence  of  this  wonderful  current  upon  the  climate  of  the 
South  ?  In  the  pursuit  of  this  subject,  the  mind  is  led  from  na- 
ture up  to  the  Great  Architect  of  nature  ;  and  what  mind  will  the 
study  of  this  subject  not  fill  with  profitable  emotions?  Un- 
changed and  unchanging  alone,  of  all  created  things,  the  ocean  is 
the  great  emblem  of  its  everlasting  Creator.  "  He  treadeth  upon 
the  waves  of  the  sea,"  and  is  seen  in  the  wonders  of  the  deep. 
.Yea,  "  He  calleth  for  its  waters,  and  poureth  them  out  upon  the 
face  of  the  earth." 

67.  In  obedience  to  this  call,  the  aqueous  portion  of  our  planet 
preserves  its  beautiful  system  of  circulation.  By  it  heat  and 
warmth  are  dispensed  to  the  extra-tropical  regions ;  clouds  and 
rain  are  sent  to  refresh  the  dry  land ;  and  by  it  cooling  streams 
are  brought  from  Polar  Seas  to  temper  the  heat  of  the  torrid  zone. 
At  the  depth  of  two  hundred  and  forty  fathoms,  the  temperature 
of  the  currents  setting  into  the  Caribbean  Sea  has  been  found  as 
low  as  48°,  while  that  of  the  surface  was  85°.  Another  cast  with 
three  hundred  and  eighty-six  fathoms  gave  43°  below  against  83° 
at  the  surface.  The  hurricanes  of  those  regions  agitate  the  sea  to 
great  depths ;  that  of  1780  tore  rocks  up  from  the  bottom  seven 
fathoms  deep,  and  cast  them  ashore.  They  therefore  can  not  fail 
to  bring  to  the  surface  portions  of- the  cooler  water  below. 

68.  At  the  very  bottom  of  the  Gulf  Stream,  when  its  surface 
temperature  was  80°,  the  deep-sea  thermometer  of  the  Coast  Sur- 
vey has  recorded  a  temperature  as  low  as  35°  Fahrenheit. 

*  Temperature  of  the  Caribbean  Sea  (from  the  journals  of  Mr.  Dunsterville) : 
Surface  temperature  :  83°,  September  ;  84°,  July  ;  83°-86i°,  Mosquito  Coast. 
Temperature  in  depth:  48°,  240  fathoms;  43°,  386  fathoms;  42°,  450  fathoms; 
43°,  500  fathoms. 


54        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

69.  These  cold  waters  doubtless  come  down  from  the  north  to 
replace  the  warm  water  sent  through  the  Gulf  Stream  to  mod- 
erate the  cold  of  Spitzbergen  ;  for  within  the  Arctic  Circle  the 
temperature  at  corresj^onding  depths  off  the  shores  of  that  island 
is  said  to  be  only  one  degree  Colder  than  in  the  Caribbean  Sea, 
while  on  the  coasts  of  Labrador  and  in  the  Polar  Seas  the  tem- 
perature of  the  water  beneath  the  ice  was  invariably  found  by 
Lieutenant  De  Haven  at  28°,  or  4°  below  the  melting  point  of 
fresh-water  ice.  Captain  Scoresby  relates,  that  on. the  coast  of 
Greenland,  in  latitude  72°,  the  temperature  of  the  air  was  42°  ; 
of  the  water,  34° ;  and  29°  at  the  depth  of  one  hundred  and  eight- 
een fathoms.  He  there  found  a  surface  current  setting  to  the 
south,  and  bearing  with  it  this  extremely  cold  water,  with  vast 
numbers  of  icebergs,  whose  centres,  perhaps,  were  far  below  zero. 
It  would  be  curious  to  ascertain  the  routes  of  these  under  cur- 
rents on  their  way  to  the  tropical  regions,  which  they  are  intend- 
ed to  cool.  One  has  been  found  at  the  equator  (§  23)  two  hundred 
miles  broad  and  23°  colder  than  the  surface  water.  Unless  the 
land  or  shoals  intervene,  it  no  doubt  comes  down  in  a  spiral  curve, 
approaching  in  its  course  the  great  circle  route. 

70.  Perhaps  the  best  indication  as  to  these  cold  currents  may 
be  derived  from  the  fish  of  the  sea.  The  whales  first  pointed  out 
the  existence  of  the  Gulf  Stream  by  avoiding  its  warm  waters. 
Along  our  own  coasts,  all  those  delicate  animals  and  marine  pro- 
ductions which  delight  in  warmer  waters  are  wanting  ;  thus  indi- 
cating, by  their  absence,  the  cold  current  from  the  north  now 
known  to  exist  tliere.  In  the  genial  warmth  of  the  sea  about  the 
Bermudas  on  one  hand,  and  Africa  on  the  other,  we  find,  in  great 
abundance,  those  delicate  shell-fish  and  coral  formations  which  are 
altogether  wanting  in  the  same  latitudes  along  the  shores  of  South 
Carolina.  The  same  obtains  in  the  west  coast  of  South  America ; 
for  there  the  cold  current  almost  reaches  the  line  before  the  first 
sprig  of  coral  is  found  to  grow. 

71.  A  few  years  ago,  great  numbers  of  bonita  and  albercore — 
tropical  fish — following  the  Gulf  Stream,  entered  the  English 
Channel,  and  alarmed  the  fishermen  of  Cornwall  and  Devonshire 
by  the  Imvoc  which  they  created  among  the  pilchards  there. 


INFLUENCE  OF  THE  GULF  STREAM  UPON  CLIMATES.  55 

72.  It  may  well  be  questioned  if  our  Atlantic  cities  and  towns 
do  not  owe  their  excellent  fisli-markets,  as  well  as  our  waterino'- 
places  their  refreshing  sea-bathing  in  summer,  to  this  stream  of 
cold  water.  The  temperature  of  the  j\Iediterranean  is  4°  or  5° 
above  the  ocean  temperature  of  the  same  latitude,  and  the  fish 
there  are,  for  the  most  part,  very  indifferent.  On  the  other  hand, 
the  temperature  along  our  coast  is  several  degrees  below  that  of 
the  ocean,  and  from  Maine  to  Florida  our  tables  are  supplied  with 
the  most  excellent  of  fish.  The  sheep's-head,  so  much  esteemed 
in  Virginia  and  the  Carolinas,  when  taken  on  the  warm  coral  banks 
of  the  Bahamas,  loses  its  flavor,  and  is  held  in  no  esteem.  The 
same  is  the  case  with  other  fish:  when  taken  in  the  cold  water 
of  that  coast,  they  have  a  delicious  flavor  and  are  higlily  esteemed; 
but  when  taken  in  the  warm  water  on  the  other  edge  of  the  Gulf 
Stream,  though  but  a  few  miles  distant,  their  flesh  is  soft  and  un- 
fit for  the  table.  The  temperature  of  the  water  at  the  Balize 
reaches  90°.  The  fish  taken  there  are  not  to  be  compared  with 
those  of  the  same  latitude  in  this  cold  stream.  New  Orleans, 
therefore,  resorts  to  the  cool  waters  on  the  Florida  coasts  for  her 
choicest  fish.  The  same  is  the  case  in  the  Pacific.  A  current 
of  cold  water  (§  455)  from  the  south  sweeps  the  shores  of  Chili, 
Peru,  and  Columbia,  and  reaches  the  Gallipagos  Islands  under  the 
line.  Throughout  this  whole  distance,  the  world  does  not  afford 
a  more  abundant  or  excellent  supply  of  fish.  Yet  out  in  the  Pa- 
cific, at  the  Society  Islands,  where  coral  abounds,  and  the  water 
preserves  a  higher  temperature,  the  fish,  though  they  vie  in  gor- 
geousness  of  coloring  with  the  birds,  and  plants,  and  insects  of  the 
tropics,  are  held  in  no  esteem  as  an  article  of  food.  I  have  known 
sailors,  even  after  long  voyages,  still  to  prefer  their  salt  beef  and 
pork  to  a  mess  of  fish  taken  there.  The  few  facts  which  we  have 
bearing  upon  this  subject  ^seem  to  suggest  it  as  a  point  of  the  in- 
quiry to  be  made,  whether  the  habitat  of  certain  fish  does  not  in- 
dicate the  temperature  of  the  water ;  and  whether  these  cold  and 
warm  currents  of  the  ocean  do  not  constitute  the  great  highways 
through  which  migratory  fishes  travel  from  one  region  to  another. 
Why  should  not  fish  be  as  much  the  creatures  of  climate  as 
plants,  or  as  birds  and  other  animals  of  land,  sea,  and  air  ?     In- 


56  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

deed,  we  know  that  some  kinds  of  fisli  are  found  only  in  certain 
climates.  In  other  words,  they  live  where  the  temperature  of  the 
water  ranges  between  certain  degrees. 

73.  Navigators  have  often  met  with  vast  numbers  of  young  sea- 
nettles  {meclusce)  drifting  along  with  the  Gulf  Stream.  Tliey  are 
known  to  constitute  the  principal  food  for  the  whale ;  but  whither 
bound  by  this  route  has  caused  much  curious  speculation,  for  it 
is  well  known  that  the  habits  of  the  right  whale  are  averse  to  the 
warm  waters  of  this  stream.  An  intelligent  sea-captain  informs 
me  that,  several  years  ago,  in  the  Gulf  Stream  on  the  coast  of 
Florida,  he  fell  in  with  such  a  "  school  of  young  sea-nettles  as  had 
never  before  been  heard  of."  The  sea  was  covered  with  them  for 
many  leagues.  He  likened  them,  in  appearance  on  the  water,  to 
acorns  floating  on  a  stream ;  but  they  were  so  thick  as  to  com- 
pletely cover  the  sea.  He  was  bound  to  England,  and  was  five 
or  six  days  in  sailing  through  them.  In  about  sixty  days  after- 
ward, on  his  return,  he  fell  in  with  the  same  school  off  the  West- 
ern Islands,  and  here  he  was  three  or  four  days  in  passing  them 
asain.  He  recoo'nized  them  as  the  same,  for  he  had  never  before 
seen  any  like  them  ;  and  on  both  occasions  he  frequently  hauled 
up  buckets  full  and  examined  them. 

74.  ISTow  the  Western  Islands  is  the  great  place  of  resort  for 
whales ;  and  at  first  there  is  something  curious  to  us  in  the  idea 
that  the  Gulf  of  ]\Iexico  is  the  harvest  field,  and  the  Gulf  Stream 
the  gleaner  which  collects  the  fruitage  planted  there,  and  conveys 
it  thousands  of  miles  off  to  the  hungry  whale  at  sea.  But  how 
perfectly  in  unison  is  it  with  the  kind  and  providential  care  of  that 
great  and  good  Being  which  feeds  the  young  ravens  when  they 
cry,  and  caters  for  the  sparrow ! 

75.  The  sea  has  its  climates  as  well  as  the  land.  They  both 
change  with  the  latitude  ;  but  one  varies  with  the  elevation  above, 
the  other  with  the  depression  below  the  sea  level.  The  climates 
in  each  are  regulated  by  circulation ;  but  the  regulators  are,  on  the 
one  hand,  winds  ;  on  the  other,  currents. 

76.  The  inliabitants  of  the  ocean  are  as  much  the  creatures  of 
climate  as  are  those  of  the  dryland  ;  for  the  same  Almighty  hand 
which  decked  the  lily  and  cares  for  the  sparrow,  fashioned  also 


INFLUENCE  OF  THE  GULF  STREAM  UPON  CLIMATES.  57 

the  pearl  and  feeds  the  great  whale,  and  adapted  each  to  the 
physical  conditions  by  which  his  providence  has  siUTOunded  it. 
Whether  of  the  land  or  the  sea,  the  inhabitants  are  all  his  crea- 
tures, subjects  of  his  laws,  and  agents  in  his  economy.  The  sea, 
therefore,  Ave  may  safely  infer,  has  its  offices  and  duties  to  per- 
form ;  so  may  we  infer,  have  its  currents,  and  so,  too,  its  inhabi- 
tants ;  consequently,  he  who  undertakes  to  study  its  phenomena 
must  cease  to  regard  it  as  a  waste  of  waters.  He  must  look  upon 
it  as  a  part  of  that  exquisite  machinery  by  which  the  harmonies 
of  nature  are  prieserved,  and  then  he  will  begin  to  perceive  the  de- 
velopments of  order  and  the  evidences  of  design ;  these  make  it  a 
most  beautiful  and  interesting  subject  for  contemplation. 

77.   To  one  who  has  never  studied  the  mechanism  of  a  watch, 
its  main-spring  or  the  balance-wheel  is  a  mere  piece  of  metal.     He 
may  have  looked  at  the  face  of  the  watch,  and,  while  he  admires 
the  motion  of  its  hands,  and  the  time  it  keeps,  or  the  tune  it  plays, 
he  may  have  wondered  in  idle  amazement  as  to  the  character  of 
the  machinery  which  is  concealed  within.     Take  it  to  pieces,  and 
shov/  him  each  part  separately ;  he  will  recognize  neither  design, 
nor  adaptation,  nor  relation  between  them  ;  but  put  them  together, 
set  them  to  work,  point  out  the  offices  of  each  spring,  wheel,  and 
cog,  explain  their  movements,  and  then  show  him  the  result ;  now 
he  perceives  that  it  is  all  one  design ;  that,  notwithstanding  the 
number  of  parts,  their  diverse  forms  and  various  offices,  and  the 
agents  concerned,  the  whole  piece  is  of  one  thought,  the  expres- 
sion of  one  idea.     He  now  3:ightly  concludes  that  when  the  main- 
spring was  fashioned  and  tempered,  its  relation  to  all  the  other 
parts  must  have  been  considered ;  that  the  cogs  on  this  wheel  are 
cut  and  regulated — ada2Jted — to  the  rachets  on  that,  &c. ;  and  his 
final  conclusion  will  be,  that  such  a  piece  of  mechanism  could  not 
have  been  produced  by  chance  ;  for  the  adaptation  of  the  parts  is 
such  as  to  show  it  to  be  according  to  design,  and  obedient  to  the 
will  of  one  intelligence.     So,  too,  when  one  looks  out  upon  the 
face  of  this -beautiful  world,  he  may  admire  its  lovely  scenery,  but 
his  admiration  can  never  grow  into  adoration  unless  he  will  take 
the  trouble  to  look  behind  and  study,  in  some  of  its  details  at 
least,  the  exquisite  system  of  machinery  by  which  such  beautiful 


58  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

results  are  brought  about.  To  liim  who  does  this,  the  sea,  with 
its  physical  geograpliy,  becomes  as  tlie  main-spring  of  a  watch ; 
its  waters,  and  its  currents,  and  its  salts,  and  its  inhabitants,  with 
their  adaptations,  as  balance-wheels,  cogs  and  pinions,  and  jewels. 
Thus  he  perceives  that  they,  too,  are  according  to  design ;  that 
they  are  the  expression  of  One  Thought,  a  unity  with  harmonies 
which  One  Intelligence,  and  One  Intelligence  alone,  could  utter. 
x4.nd  when  he  has  arrived  at  this  point,  then  he  feels  that  the  study 
of  the  sea,  in  its  physical  aspect,  is  truly  sublime.  It  elevates 
the  mind  and  ennobles  the  man.,  The  Gulf  Stream  is  now  no 
longer,  therefore,  to  be  regarded  by  such  an  one  merely  as  an  im- 
mense current  of  warm  water  running  across  the  ocean,  but  as  a 
balance-wheel — a  part  of  that  grand  machinery  by  which  air  and 
water  are  adapted  to  each  other,  and  by  which  this  earth  itself  is 
adapted  to  the  well-being  of  its  inhabitants — of  the  flora  which 
decks,  and  the  fauna  which  enlivens  its  surface. 

78.  Let  us  now  consider  the  influence  of  the  Gulf  Stream  upon 
the  meteorology  of  the  ocean. 

To  use  a  sailor  expression,  the  Gulf  Stream  is  the  great  "weath- 
er breeder"  of  the  JSTorth  Atlantic  Ocean.  The  most  furious  gales 
of  wind  sweep  along  with  it ;  and  the  fogs  of  Newfoundland, 
which  so  much  endanger  navigation  in  winter,  doubtless  owe  their 
existence  to  the  presence,  in  that  cold  sea,  of  immense  volumes  of 
warm  water  brought  by  the  Gulf  Stream.  Sir  Philip  Brooke 
found  the  air  on  each  side  of  it  at  the  freezing  point,  while  that 
of  its  waters  was  80°.  "  The  heavy,  warm,  damp  air  over  the 
current  produced  great  irregularities  in  his  chronometers."  The 
excess  of  heat  daily  brought  into  such  a  region  by  the  waters  of 
the  Gulf  Stream  would,  if  suddenly  stricken  from  them,  be  suffi- 
cient to  make  the  column  of  superincumbent  atmosphere  hotter 
than  melted  iron. 

79.  With  such  an  element  of  atmospherical  disturbance  in  its 
bosom,  we  might  expect  storms  of  the  most  violent  kind  to  ac- 
company it  in  its  course.  Accordingly,  the  most  terrific  that 
rage  on  the  ocean  have  been  known  to  spend  their  fury  witliin  or 
near  its  borders. 

80.  Our  nautical  works  tell  us  of  a  storm  which  forced  this 


INFLUENCE  OF  THE  GULF  STREAM  UPON  CLDL\TES.  59 

stream  back  to  its  sources,  and  piled  up  the  water  in  the  Gulf  to 
the  height  of  thirty  feet.  The  Ledbury  Snow  attempted  to  ride 
it  out.  When  it  abated,  she  found  herself  high  up  on  the  dry 
land,  and  discovered  that  she  had  let  go  her  anchor  among  the  tree- 
tops  on  Elliott's  Key.  The  Florida  Keys  were  inundated  many 
feet,  and,  it  is  said,  the  scene  p^sented  in  the  Gulf  Stream  was 
never  surpassed  in  awful  sublimff)^  on  the  ocean.  The  water  thus 
dammed  up  is  said  to  have  rushed  out  with  wonderful  velocity 
against  the  fury  of  the  gale,  producing  a  sea  that  beggared  de- 
scription. 

81.  The  "  2:reat  hurricane"  of  1780  commenced  at  Barbadoes. 
In  it  the  bark  was  blown  from  the  trees,  and  the  fruits  of  the 
earth  destroyed ;  the  very  bottom  and  depths  of  the  sea  were  up- 
rooted, and  the  waves  rose  to  such  a  height  that  forts  and  castles 
were  washed  away,  and  their  great  guns  carried  about  in  the  air 
like  chaff;  houses  were  razed,  ships  were  wrecked,  and  the  bodies 
of  men  and  beasts  lifted  up  in  the  air  and  dashed  to  pieces  in  the 
storm.  At  the  different  islands,  not  less  than  twenty  thousand 
persons  lost  their  lives  on  shore,  while  farther  to  the  north,  the 
"Sterling  Castle"  and  the  "Dover  Castle,"  men-of-war,  went 
down  at  sea,  and  fifty  sail  were  driven  on  shore  at  the  Bermudas. 

82.  Several  years  ago  the  British  Admiralty  set  on  foot  inqui- 
ries as  to  the  cause  of  the  storms  in  certain  parts  of  the  Atlantic, 
which  so  often  rage  with  disastrous  effects  to  navigation.  The 
result  may  be  summed  up  in  the  conclusion  to  which  the  investi- 
gation led :  that  they  are  occasioned  by  the  irregularity  between 
the  temperature  of  the  Gulf  Stream  and  of  the  neighboring  regions, 
both  in  the  air  and  water. 

83.  The  habitual  dampness  of  the  climate  of  the  British  Isl- 
ands, as  well  as  the  occasional  dampness  of  that  along  the  Atlan- 
tic coasts  of  the  United  States  when  easterly  winds  prevail,  is  at- 
tributable also  to  the  Gulf  Stream.  These  winds  come  to  us  load- 
ed with  vapors  gathered  from  its  warm  and  smoking  waters.  The 
Gulf  Stream  carries  the  temperature  of  summer,  even  in  the  dead 
of  winter,  as  far  north  as  the  Grand  Banks  of  Newfoundland. 

84.  One  of  the  poles  of  maximum  cold  is,  according  to  theory, 
situated  in  latitude  80°  north,  longitude  100°  west.     It  is  distant 


60        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

but  little  more  than  tivo  thousand  miles,  in  a  northwestwardly  di- 
rection, from  the  summer-heated  waters  of  this  stream.  This 
proximity  of  extremes  of  greatest  cold  and  summer  heat  will,  as 
observations  are  multij^lied  and  discussed,  be  probably  found  to 
have  much  to  do  with  the  storms  that  rage  with  such  fury  on  the 
left  side  of  the  Gulf  Stream. 

85.  I  am  not  prepared  to  maintain  that  the  Gulf  Stream  is 
really  the  "  Storm  King"  of  the  Atlantic,  which  has  power  to  con- 
trol the  march  of  every  gale  that  is  raised  there ;  but  the  course 
of  many  gales  has  been  traced  from  the  place  of  their  origin  di- 
rectly to  the  Gulf  Stream.  Gales  that  take  their  rise  on  the  coast 
of  i^frica,  and  even  as  far  down  on  that  side  as  the  parallel  of  10° 
or  15°  north  latitude,  have,  it  has  been  shown  by  an  examination 
of  log-books,  made  straight  for  the  Gulf  Stream  ;  joining  it,  they 
have  then  been  known  to  turn  about,  and,  traveling  with  this 
stream,  to  recross  the  Atlantic,  and  so  reach  the  shores  of  Europe. 
In  this  way  the  tracks  of  storms  have  been  traced  out  and  follow- 
ed for  a  week  or  ten  days.  Their  path  is  marked  by  wreck  and 
disaster.  At  the  meeting  of  the  American  Association  for  the  ad- 
vancement of  Science  in  1854,  Mr.  Hedfield  mentioned  one  which 
he  had  traced  out,  and  in  which  no  less  than  seventy  odd  vessels 
had  been  wrecked,  dismasted,  or  damaged. 

86.  Plate  X.  was  prepared  by  Lieutenant  B.  S.  Porter,  from 
data  furnished  by  the  log-books  at  the  Observatory.  It  represents 
one  of  these  storms  that  commenced  in  August,  1848.  It  com- 
menced more  than  a  thousand  miles  from  the  Gulf  Stream,  made 
a  straight  course  for  it,  and  traveled  with  it  for  many  days. 

The  dark  shading  shows  the  space  covered  by  the  gale,  and  the 
white  line  in  the  middle  shows  the  axis  of  the  gale,  or  the  line  of 
minimum  barometric  pressure.  There  are  many  other  instances 
of  similar  gales.  Professor  Espy  informs  us  that  he  also  has 
traced  many  a  gale  from  the  land  out  toward  the  Gulf  Stream. 

87.  Now  what  should  attract  these  terrific  storms  to  the  Gulf 
Stream?  Sailors  dread  storms  in  the  Gulf  Stream  more  than 
they  do  in  any  other  part  of  the  ocean.  It  is  not  the  fury  of  the 
storm  alone  that  they  dread,  but  it  is  the  "  ugly  sea"  which  these 
storms  raise.     The  current  of  the  stream  running  in  one  direc- 


INFLUENCE  OF  THE  GULF  STREAM  UPON  CLIMATES.  Ql 

tion,  and  the  wind  blowing  in  another,  creates  a  sea  that  is  often 
frightful. 

88.  In  the  month  of  Decemher,  1853,  the  fine  new  steam-ship 
San  Francisco  sailed  from  New  York  with  a  regiment  of  United 
States  troops  on  board,  bound  around  Cape  Horn  for  California. 
She  was  overtaken,  while  crossing  the  Gulf  Stream,  by  a  gale  of 
wind,  in  which  she  was  dreadfully  crippled.  Her  decks  were 
swept,  and  by  one  single  blow  of  those  terrible  seas  that  the 
storms  there  raise,  one  hundred  and  seventy-nine  souls,  officers 
and  soldiers,  were  washed  overboard  and  drowned. 

The  day  after  this  disaster  she  was  seen  by  one  vessel,  and 
again  the  next  day,  December  26th,  by  another,  but  neither  of 
them  could  render  her  any  assistance. 

When  these  two  vessels  arrived  in  the  United  States  and  re- 
ported what  they  had  seen,  the  most  painful  apprehensions  were 
entertained  by  friends  for  the  safety  of  those  on  board  the  steam- 
er. Vessels  were  sent  out  to  search  for  and  relieve  her.  But 
which  way  should  these  vessels  go  ?  where  should  they  look  ? 

An  appeal  was  made  to  know  what  light  the  system  of  re- 
searches carried  on  at  the  National  Observatory  concerning  winds 
and  currents  could  throw  upon  the  subject. 

89.  The  materials  that  had  been  discussed  were  examined,  and 
a  chart  was  prepared  to  show  the  course  of  the  Gulf  Stream  at 
that  season  of  the  year.  (See  the  limits  of  the  Gulf  Stream  for 
March,  Plate  VI.)  Upon  the  supposition  that  the  steamer  had  been 
completely  disabled,  the  lines  a  h  were  drawn  to  define  the  limits 
of  her  drift.  Between  these  two  lines,  it  was  said,  the  steamer,  if 
she  could  neither  steam  nor  sail  after  the  gale,  had  drifted, 

90.  By  request,  I  prepared  instructions  for  two  revenue  cutters 
that  were  sent  to  search  for  her.  One  of  them,  being  at  New 
London,  was  told  to  go  along  the^  dotted  track  leading  to  c,  ex- 
pecting thereby  to  keep  inside  of  the  line  along  which  the  steamer 
had  drifted,  with  the  view  of  intercepting  and  speaking  homeward- 
bound  vessels  that  mio-ht  have  seen  the  wreck. 

91.  The  cutter  was  to  proceed  to  <?,  where  she  might  expect  to 
fall  in  with  the  line  of  drift  taken  by  the  steamer.  The  last  that 
was  seen  of  that  ill-fated  vessel  was  when  she  was  at  (?,  but  a  few 


62  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

miles  from  c.  So,  if  the  cutter  had  been  in  time,  she  had  instruc- 
tions that  would  have  taken  her  in  sight  of  the  object  of  her 
search. 

92.  It  is  true  that,  before  the  cutter  sailed,  the  Kilby,  the 
Three  Bells,  and  the  Antarctic,  unknown  to  anxious  friends  at 
home,  had  fillen  in  with  and  relieved  the  wreck ;  but  that  does 
not  detract  from  the  system  of  observations,  of  the  results  of 
which,  and  their  practical  application,  it  is  the  object  of  this  work 
to  treat. 

93.  A  beautiful  illustration  of  their  usefulness  is  the  fact  that, 
though  the  bark  Kilby  lost  sight  of  the  wreck  at  night,  and  the 
next  morning  did  not  know  which  way  to  look  for  it,  and  could 
not  find  it,  yet,  by  a  system  of  philosophical  deduction,  we  on 
shore  could  point  out  the  whereabouts  of  the  disabled  steamer  so 
closely,  that  vessels  could  be  directed  to  look  for  her  exactly 
where  she  was  to  be  seen. 

94.  These  storms,  for  which  the  Gulf  Stream  has  such  attrac- 
tion, and  over  which  it  seems  to  exercise  so  much  control,  are 
said  to  be,  for  the  most  part,  whirlwinds.  All  boys  are  familiar 
with  miniature  Avliirlwinds  on  shore.  They  are  seen,  especially 
in  the  autumn,  sweeping  along  the  roads  and  streets,  raising  col- 
umns of  dust,  leaves,  etc.,  which  rise  up  like  inverted  cones  in  the 
air,  and  gyrate  about  the  centre  or  axis  of  the  storm.  Thus, 
while  the  axis,  and  the  dust,  and  the  leaves,  and  all  those  things 
which  mark  the  course  of  the  whirlwind,  are  traveling  in  one  di- 
rection, it  may  be  seen  that  the  wind  is  blowing  around  this  axis 
in  all  directions. 

Just  so  with  some  of  these  Gulf  Stream  storms.  That  repre- 
sented on  Plate  X.  is  such  a  one.  It  was  a  rotary  storm.  Mr. 
Piddington,  an  eminent  meteorologist  of  Calcutta,  calls  them  Cy- 
clones. 

95.  Now,  what  should  make  these  storms  travel  toward  the 
Gulf  Stream,  and  then,  joining  it,  travel  along  with  its  current  ? 
It  is  tlie  liigh  temperature  of  its  waters,  say  mariners.  But  why, 
or  wherefore,  should  the  spirits  of  the  storm  obey  in  this  manner 
the  influence  of  these  high  temperatures,  philosophers  have  not 
been  able  to  explain. 


INFLUENCE  OF  THE  GULF  STREAM  UPON  COMMERCE.         Q^ 

96.  T/ie  influence  of  the  Gulf  Stream  tqoon  commerce  and 
navigation. 

Formerly  the  Gulf  Stream  controlled  commerce  across  the  At- 
lantic by  governing  vessels  in  their  routes  through  this  ocean  to 
a  greater  extent  than  it  does  now,  and  simply  for  the  reason  that 
ships  are  faster,  nautical  instruments  better,  and  navigators  are 
more  skillful  now  than  formerly  they  were. 

97.  Up  to  the  close  of  the  last  century,  the  navigator  guessed 
as  much  as  he  calculated  the  place  of  his  ship :  vessels  from  Eu- 
rope to  Boston  frequently  made  New  York,  and  thought  the  land- 
fall by  no  means  bad.  Chronometers,  now  so  accurate,  were  then 
an  experiment.  The  Nautical  Ephemeris  itself  was  faulty,  and 
gave  tables  which  involved  errors  of  thirty  miles  in  the  longitude. 
The  instruments  of  navigation  erred  by  degrees  quite  as  much  as 
they  now  do  by  oninutes ;  for  the  rude  "cross  staff"  and  "back 
staff,"  the  "sea-ring"  and  "mariners  bow,"  had  not  yet  given 
place  to  the  nicer  sextant  and  circle  of  reflection  of  the  present 
day.  Instances  are  numerous  of  vessels  navigating  the  Atlantic 
in  those  times  being  6°,  8°,  and  even  10°  of  longitude  out  of  their 
reckoning  in  as  many  days  from  port. 

98.  Though  navigators  had  been  in  the  habit  of  crossing  and 
recrossing  the  Gulf  Stream  almost  daily  for  three  centuries,  it 
never  occurred  to  them  to  make  use  of  it  as .  a  means  of  giving 
them  their  longitude,  and  of  warning  them  of  their  approach  to 
the  shores  of  this  continent. 

99.  Dr.  Franklin  was  the  first  to  suggest  this  use  of  it.  The 
contrast  afforded  by  the  temperature  of  its  waters  and  that  of  the 
sea  between  the  Stream  and  the  shores  of  America  was  strikino-. 
The  dividing  line  between  the  warm  and  the  cool  waters  was 
sharp  (§  2) ;  and  this  dividing  line,  especially  that  on  the  western 
side  of  the  stream,  never  changed  its  position  as  much  in  longitude 
as  mariners  erred  in  their  reckoning. 

100.  When  he  was  in  London  in  1770,  he  happened  to  be  con- 
sulted as  to  a  memorial  which  the  Board  of  Customs  at  Boston 
sent  to  the  Lords  of  the  Treasury,  stating  that  the  Falmouth  pack- 
ets were  generally  a  fortnight  longer  to  Boston  than  common  trad- 
ers were  from  London  to  Providence,  Ehode  Island.     They  there- 


64        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

fore  asked  that  the  Fahnouth  packets  might  be  sent  to  Providence 
instead  of  to  Boston.  This  appeared  strange  to  the  doctor,  for 
London  was  much  farther  than  Fahnouth,  and  from  Falmouth  the 
routes  were  the  same,  and  the  difference  should  have  hcen  the 
other  way.  He,  liowever,  consulted  Captain  Folger,  a  Nantucket 
whaler,  who  chanced  to  be  in  London  also ;  the  fisherman  ex- 
plained to  him  that  the  difference  arose  from  the  circumstance 
that  the  Rhode  Island  captains  were  acquainted  with  the  Gulf 
Stream,  while  those  of  the  English  packets  were  not.  The  latter 
kept  in  it,  and  were  set  back  sixty  or  seventy  miles  a  day,  while 
the  former  avoided  it  altogether.  He  had  been  made  acquainted 
with  it  by  the  whales  which  were  found  on  either  side  of  it,  but 
never  in  it  (§  70).  At  the  request  of  the  doctor,  he  then  traced 
on  a  chart  the  course  of  this  stream  from  the  Straits  of  Florida. 
The  doctor  had  it  engraved  at  Tower  Hill,  and  sent  copies  of  it  to 
the  Falmouth  captains,  who  paid  no  attention  to  it.  The  course 
of  the  Gulf  Stream,  as  laid  down  by  that  fisherman  from  his  gen- 
eral recollection  of  it,  has  been  retained  and  quoted  on  the  charts 
for  navigation,  we  may  say,  until  the  present  day. 

But  the  investigations  of  which  we  are  treating  are  beginning 
to  throw  more  light  upon  this  subject ;  they  are  giving  us  more 
correct  knowledge  in  every  respect  with  regard  to  it,  and  to  many 
other  new  and  striking  features  in  the  physical  geography  of  the 
sea. 

101.  No  part  of  the  world  affords  a  more  difficult  or  dangerous 
navigation  than  the  approaches  of  our  northern  coast  in  winter. 
Before  the  warmth  of  the  Gulf  Stream  was  known,  a  voyage  at 
this  season  from  Europe  to  New  England,  New  York,  and  even 
to  the  Capes  of  the  Delaware  or  Chesapeake,,  was  many  times 
more  trying,  difficult,  and  dangerous  than  it  now  is.  Li  making 
this  part  of  the  coast,  vessels  are  frequently  met  by  snow-storms 
and  gales  which  mock  the  seaman's  strength  and  set  at  naught 
his  skill.  In  a  little  while  his  bark  becomes  a  mass  of  ice  ;  with 
her  crew  frosted  and  helpless,  she  remains  obedient  only  to  her 
helm,  and  is  kept  away  for  the  Gulf  Stream.  After  a  few  hours' 
run,  she  reaches  its  edge,  and  almost  at  the  next  bound  passes 
from  the  midst  of  winter  into  a  sea  at  summer  heat.     Now  the  ice 


INFLUENCE  OF  THE  GULF  STREAM  UPON  COMMERCE.         65 

disappears  from  her  apparel ;  the  sailor  bathes  his  stiffened  limbs 
in  tepid  waters ;  feeling  himself  invigorated  and  refreshed  with 
the  genial  warmth  about  him,  he  realizes,  out  there  at  sea,  the  fa- 
ble of  Antaeus  and  his  mother  Earth.  He  rises  up  and  attempts 
to  make  his  port  again,  and  is  again,  perhaps,  as  rudely  met  and 
beat  back  from  the  northwest ;  but  each  time  that  he  is  driven  off 
from  the  contest,  he  comes  forth  from  this  stream,  like  the  ancient 
son  of  Neptune,  stronger  and  stronger,  until,  after  many  days,  his 
freshened  strength  prevails,  and  he  at  last  triumphs  and  enters  his 
haven  in  safety,  though  in  this  contest  he  sometimes  falls  to  rise 
no  more,  for  it  is  often  terrible.  !Many  ships  annually  founder  in 
these  gales  ;  and  I  might  name  instances,  for  they  are  not  uncom- 
mon, in  which  vessels  bound  to  Norfolk  or  Baltimore,  with  their 
crews  enervated  in  tropical  climates,  have  encountered,  as  far  down 
as  the  Capes  of  Virginia,  snow-storms  that  have  driven  them  back 
into  the  Gulf  Stream  time  and  again,  and  have  kept  them  out  for 
forty,  fifty,  and  even  for  sixty  days,  trying  to  make  an  anchorage. 

102.  Nevertheless,  the  presence  of  the  warm  waters  of  the  Gulf 
Stream,  with  their  summer  heat  in  mid-winter,  off  the  shores  of 
New  England,  is  a  great  boon  to  navigation.  At  this  season  of 
the  year  especially,  the  number  of  wrecks  and  the  loss  of  life  along 
the  Atlantic  sea-front  are  frightful.  The  month's  average  of 
wrecks  has  been  as  high  as  three  a  day.  How  many  escape  by 
seekino;  refuo;e  from  the  cold  in  the  warm  waters  of  the  Gulf 
Stream  is  matter  of  conjecture.  Suffice  it  to  say,  that  before  their 
temperature  was  known,  vessels  thus  distressed  knew  of  no  place 
of  refuge  short  of  the  West  Indies  ;  and  the  newspapers  of  that 
day — -Franklin's  Pennsylvania  Gazette  among  them — inform  us 
that  it  was  no  uncommon  occurrence  for  vessels,  bound  for  the 
Capes  of  the  Delaware  in  winter,  to  be  blown  off  and  to  go  to  the 
West  Indies,  and  there  wait  for  the  return  of  spring  before  they 
would  attempt  another  approach  to  this  part  of  the  coast. 

103.  xVccordingly,  Dr.  Franklin's  discovery  with  regard  to  the 
Gulf  Stream  temperature  was  looked  upon  as  one  of  great  import- 
ance, not  only  on  account  of  its  affording  to  the  frosted  mariner  in 
winter  a  convenient  refuo-e  from  the  snow-storm,  but  because  of 
its  serving  the  navigator  with  an  excellent  land-mark  or  beacon 


(56  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

for  our  coast  in  all  weathers.  And  so  viewing  it,  the  doctor, 
through  political  considerations,  concealed  his  discovery  for  a  while. 
It  was  then  not  uncommon  for  vessels  to  be  as  much  as  10°  out 
in  their  reckoning,  lie  himself  was  5°.  The  prize  of  £20,000, 
which  had  Ibeen  oilered,  and  'partly  paid  to  Harrison,  the  chro- 
nometer maker,  for  improving  the  means  of  finding  longitude  at 
sea,  was  fresh  in  the  minds  of  navigators.  And  here  it  was  thought 
a  solution  of  the  grand  problem — for  longitude  at  sea  was  a  grand 
problem — liad  been  stumbled  upon  by  chance ;  for,  on  approach- 
ing llic  coast,  the  current  of  warm  water  in  the  Gulf  Stream,  and 
of  cold  water  on  this  side  of  it,  if  tried  with  the  thermometer, 
would  enable  the  mariner  to  judge  with  great  certainty,  and  in  the 
worst  of  weather,  as  to  his  position.  Jonathan  Williams  after' 
ward,  in  speaking  of  the  importance  which  the  discovery  of  these 
Avarm  and  cold  currents  would  prove  to  navigation,  pertinently 
asked  the  question,  "If  these  stripes  of  water  had  been  distin- 
guished by  the  colors  of  red,  white,  and  blue,  could  they  be  more 
distinctly  discovered  than  they  are  by  the  constant  use  of  the 
thermometer  ?"  And  he  might  have  added,  could  they  have  mark- 
ed the  position  of  the  ship  more  clearly  ? 

104.  When  his  work  on  Thermometrical  Navigation  appeared. 
Commodore  Truxton  wrote  to  him:  "Your  publication  will  be 
of  use  to  navigation  by  rendering  sea  voyages  secure  far  beyond 
what  even  you  yourself  will  immediately  calculate,  for  I,  have 
proved  the  utility  of  the  thermometer  very  often  since  we  sailed 
together. 

"  It  will  be  found  a  most  valuable  instrument  in  the  hands  of 
mariners,  and  particularly  as  to  those  who  are  unacquainted  with 

astronomical  observations  ; these  particularly  stand  in  need 

of  a  simple  method  of  ascertaining  their  approach  to  or  distance 
from  the  coast,  especially  in  the  winter  season ;  for  it  is  then  that 
passages  are  often  prolonged,  and  ships  blown  off  the  coast  by 
hard  westerly  winds,  and  vessels  get  into  the  Gulf  Stream  with- 
out its  being  known ;  on  which  account  they  are  often  hove  to  by 
the  captains'  supposing  themselves  near  the  coast  when  they  are 
very  far  off  (having  been  drifted  by  the  currents).  On  the  other 
hand,  ships  are  often  cast  on  the  coast  by  sailing  in  the  eddy  of 


INFLUENCE  OF  THE  GULF  STREAM  UPON  COMMERCE.    Ql 

the  Stream,  wliicli  causes  them  to  outrun  tlicir  eommon  reckon- 
ing. Every  year  produces  new  proofs  of  these  facts,  and  of  the 
calamities  incident  thereto." 

105.  Though  JJr.  Franklin's  discovery  was  made  in  1775,  yet, 
for  political  reasons,  it  was  not  generally  made  known  till  1790. 
Its  immediate  effect  in  navigation  was  to  make  the  ports  of  the 
North  as  accessible  in  winter  as  in  summer.  What  agency  this 
circumstance  had  in  the  decline  of  the  direct  trade  of  the  South, 
which  followed  this  discovery,  would  be,  at  least  to  the  political 
economist,  a  subject  for  much  curious  and  interesting  speculation. 
I  have  referred  to  the  commercial  tables  of  tlie  time,  and  have 
compared  the  trade  of  Charleston  with  that  of  the  northern  cities 
for  several  years,  both  before  and  after  the  discovery  of  Dr.  Frank- 
lin became  generally  known  to  navigators.  The  comparison  shows 
an  immediate  decline  in  tlie  Southern  trade  and  a  wonderful  in- 
crease in  that  of  tlie  Nortli.  i>ut  whether  this  discovery  in  nav- 
igation and  this  revolution  in  trade  stand  in  the  relation  of  cause 
and  effect,  or  be  merely  a  coincidence,  let  others  judge. 

lOG.  In  17G9,  the  commerce  of  tlic  two  Carolinas  equaled  that 
of  all  the  New  England  States  together ;  it  was  more  than  douljle 
that  of  New  York,  and  exceeded  that  of  Pennsylvania  by  one 
third.*  In  1792,  the  exports  from  New  York  amounted  in  value 
to  two  millions  and  a  half;  from  Pennsylvania,  to  $3,820,000; 
and  from  Charleston  alone,  to  $3,834,000. 

107.  Viut  in  1795 — by  which  time  the  Gulf  Stream  began  to  be 
as  well  understood  by  navigators  as  it  now  is,  and  the  average 
passages  from  Europe  to  the  North  were  shortened  nearly  one 
half,  wliile  those  to  the  South  remained  about  the  same — tlic  cus- 


*  From  M'Pher son's  Annals  of  Commerce. — Exports  and  Imports  in  1769,  valued  in 

Sterling  Money. 


EXPORTS. 


To  Gr.  Britain. 

Son.  of  Kurope. 

West  Indies. 

Africa.                Total.        1 

New  Eriftland 

£        s.d. 
142,775  12  9 

ij;i,:j82   8  8 

28,112     0  9 
405,014  13  1 

£        s.    d. 

81,173  10     2 

50,885  13     0 

20.V<12  11   11 

70,119  12  10 

£         s.  d. 

308,427     9     fi 
CO,  .'{24  17    5 

178,331     7     8 
87,758  19     3 

£       .s.d.       £        s.d. 
17,713     0  9  550.089  19  'J 

New  York 

1,313     2  0 
500    9  9 
091   12  1 

231,900     1   7 
4 10, 7.00  10  1 
509,584  17  3 

PeniiHylvania 

North  and  South  Carolina  ,  . . 

New  England  

223,695  11  6 

75,930  19  7 

204,979  17  4 

327,084    8  C 

IMPORTS. 

25,408  17    9 
14,927    7 
14,249     8    4 
7,099     5  10 

314,749  14    5 

897,420     4     0 

180,591    12     4 

70,269  17  n 

180    0  0 

097  10  0 

137,020  10  0 

504,034    3  8 
1HH,970     1  3 
399.H30  18  0 
535,714     2  3 

New  York 

Pennsylvania 

North  and  South  Carolina . . . 

E 


68 


THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


toms  at  Philadelphia  alone  amounted  to  $2,941,000,*  or  more  than 
one  half  of  those  collected  in  all  the  states  together. 

108.  Nor  did  the  effect  of  the  doctor's  discovery  end  here.  Be- 
fore it  was  made,  the  Gulf  Stream  was  altogether  insidious  in  its 
effects.  By  it,  vessels  were  often  drifted  many  miles  out  of  their 
course  witliout  knowing  it ;  and  in  bad  and  cloudy  weather,  when 
many  days  would  intervene  from  one  observation  to  another,  the 
set  of  the  current,  though  really  felt  for  but  a  few  hours  during  the 
interval,  could  only  be  proportioned  out  equally  among  the  whole 
number  of  days.  Therefore  navigators  could  have  only  very  vague 
ideas  either  as  to  the  strength  or  the  actual  limits  of  the  Gulf 
Stream,  until  they  were  marked  out  to  the  Nantucket  fishermen 
by  the  whales,  or  made  known  by  Captain  Folger  to  Dr.  Franklin. 
The  discovery,  therefore,  of  its  high  temperature  assured  the  nav- 
igator of  the  presence  of  a  current  of  surprising  velocity,  and  which, 
now  turned  to  certain  account,  would  hasten,  as  it  had  retarded 
his  voyage  in  a  wonderful  degree. 

109.  Such,  at  the  present  day,  is  the  degree  of  perfection  to 
which  nautical  tables  and  instruments  have  been  brought,  that 
the  navigator  may  now  detect,  and  with  great  certainty,  every 
current  that  thwarts  his  way.  He  makes  great  use  of  them. 
Colonel  Sabine,  in  his  passage,  a  few  years  ago,  from  Sierra  Le- 
one to  New  York,  was  drifted  one  thousand  six  hundred  miles  of 
his  way  by  the  force  of  currents  alone ;  and,  since  the  application 
of  the  thermometer  to  the  Gulf  Stream,  the  average  passage  from 
England  has  been  reduced  from  upward  of  eight  weeks  to  a  little 
more  than  four. 

110.  Some  political  economists  of  America  have  ascribed  the 
great  decline  of  Southern  commerce  which  followed  the  adoption  of 

*  Value  of  Exports  in  Dollars. ^ 


Massachusetts  . 

New  York 

Pennsylvania. . 
South  Carolina 


1791. 


nfl-2. 


2.519,651 

2;505,465 
3,436,000 
2,693,000 


2,888,104 
2,535,790 
3,820,000 
2,428,000 


3,755,347 
2,932,370 
6,958,000 
3,191,000 


5,292,441 
5,442,000 
6,643,000 

3,868,000 


1795. 


7,117,907 
10,304,000 
11,518,000 

5,998,000 


9,949,345 

12,208.027 

17,513,866 

7,620,000 


Duties  on  Imports  in 

Dollars. 

1791.        1        179-2. 

1793. 

1794.                1795. 

1796. 

1833. 

Massachusetts 

New  Yorlv   

1,006,000       723,000 

1,334^000    1,173.000 

1,466,000    1,100,000 

523,000       359.000 

1,044,000 

1,204,000 

1,823,000 

360,000 

1,121,000 

1,878,000 

1,498,000 

661,000 

1,520,000 

2,028,000 

2,300,000 

722,000 

1,460,000 

2,187,000 

2,050,000 

66,000 

3,055,000 

10,713,000 

2,207,000 

389,000 

Pennsvivania 

South  Carolina 

1  Doc.  No.  330,  H.  R.,2d  Session,  25th  Congress.     Some  of  its  statements  do  not  agree  with  those 
taken  from  M'Pherson  and  previously  quoted. 


INFLUENCE  OF  THE  GULF  STREAM  UPON  COMMERCE.         69 

the  Constitution  of  the  United  States  to  the  protection  given  hj 
legislation  to  Northern  interests.     But  I  think  these  statements 

o 

and  figures  show  that  this  decline  was  in  no  small  degree  owing 
to  the  Gulf  Stream  and  the  water  thermometer ;  for  they  changed 
the  relations  of  Charleston — the  great  Southern  emporium  of  the 
times — removing  it  from  its  position  as  a  half-way  house,  and 
placing  it  in  the  category  of  an  outside  station. 

111.  The  plan  of  our  work  takes  us  necessarily  into  the  air,  for 
the  sea  derives  from  the  winds  some  of  the  most  striking  features 
in  its  physical  geography.  Without  a  knowledge  of  the  winds, 
we  can  neither  understand  the  navigation  of  the  ocean,  nor  make 
ourselves  intelligently  acquainted  with  the  gTcat  highways  across 
it.  As  with  the  land,  so  with  the  sea ;  some  parts  of  it  are  as  un- 
traveled  and  as  unknown  as  the  great  Amazonian  wilderness  of 
Brazil,  or  the  inland  basins  of  Central  Africa.  To  the  south  of  a 
line  extending  from  Cape  Horn  to  the  Cape  of  Good  Hope  (Plate 
Vni.)  is  an  immense  waste  of  waters.  None  of  the  commercial 
thoroughfares  of  the  ocean  lead  through  it ;  only  the  adventurous 
whaleman  finds  his  way  there  now  and  then  in  pursuit  of  his 
game ;  but  for  all  the  jDurposes  of  science  and  navigation,  it  is  a 
vast  unknown  region.  Now,  were  the  prevailing  winds  of  the 
South  Atlantic  northerly  or  southerly,  instead  of  easterly  or  west- 
erly, this  unplowed  sea  would  be  an  oft-used  thoroughfare. 

112.  Nay,  more,  the  sea  supplies  the  winds  with  food  for  the 
rain  which  these  busy  messengers  convey  away  from  the  ocean  to 
"the  springs  in  the  valleys  which  run  among  the  hills."  To  the 
philosopher,  the  places  which  supply  the  vapors  are  as  suggestive 
and  as  interesting  for  the  instruction  they  afford,  as  the  places  are 
upon  which  the  vapors  are  showered  down.  Therefore,  as  he  who 
studies  the  physical  geography  of  the  land  is  expected  to  make 
himself  acquainted  with  the  regions  of  precipitation,  so  he  who 
looks  into  the  physical  geography  of  the  sea  should  search  for  the 
regions  of  evaporation,  and  for  those  sj)ring3  in  the  ocean  which 
supply  the  reservoirs  among  the  mountains  with  water  to  feed  the 
rivers  ;  and,  in  order  to  conduct  this  search  properly,  he  must  con- 
sult the  winds,  and  make  himself  acquainted  with  their  "  circuits." 
Hence,  in  a  work  on  the  Physical  Geography  of  the  Sea,  we  treat 
also  of  the  Atmosphere. 


70  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  III. 

THE    ATMOSPHERE. 

Its  Connection  with  the  Physical  Geography  of  the  Sea,  <$»  113. — Description,  uii4. — 
Order  in  Sea  and  Air,  119. — The  Language  and  Eloquence  of  Nature,  120. — The 
Trade-winds,  122. — Plate  I.,  Circulation  of  the  Atmosphere,  123. — An  Illustration, 
126. — Theory,  128. — Where  and  why  the  Barometer  stands  highest,  133. — The 
Pleiades,  142. — Trade-wind  Clouds,  146. — Forces  concerned,  149. — Heat  and  Cold. 
150. — How  the  Winds  turn  about  the  Poles,  155. — Offices  of  the  Atmosphere,  159. 
— Mechanical  Power  of,  167. — Whence  come  the  Rains  for  the  Northern  Hemi- 
sphere'? 169. — Quantity  of  Rain  in  each  Hemisphere,  175. — The  saltest  Portion  of 
the  Sea,  179. — The  Northeast  Trade-winds  take  up  Vapors  far  the  Southern  Hem- 
isphere, 181. — Rainy  Seasons,  187. — In  Oregon,  189. — Cahfornia,  191. — Panama, 
193.— Rainless  Regions,  194.— Rainy  Side  of  Mountains,  199.— The  Ghauts,  200. 
— The  greatest  Precipitation — where  it  takes  place,  203. — Evaporation,  207. — Rate 
of,  in  India,  210. — Adaptations  of  the  Atmosphere,  219. 

113.  A  rHiLOSOPHER  of  the  East,*  witli  a  riclmess  of  imagery 
truly  Oriental,  describes  tlie  atmospliere  as  "a  spherical  shell 
which  surrounds  our  planet  to  a  depth  which  is  unknown  to  us, 
by  reason  of  its  growing  tenuity,  as  it  is  released  from  the  press- 
ure of  its  own  superincumbent  mass.  Its  upper  surface  can  not 
be  nearer  to  us  than  fifty,  and  can  scarcely  be  more  remote  than 
five  hundred  miles.  It  surrounds  ns  on  all  sides,  yet  we  see  it 
not ;  it  presses  on  us  with  a  load  of  fifteen  pounds  on  every  square 
inch  of  surface  of  our  bodies,  or  from  seventy  to  one  hundred  tons 
on  us  in  all,  yet  we  do  not  so  much  as  feel  its  weight.  Softer 
than  the  softest  down — more  impalpable  than  the  finest  gossamer 
— it  leaves  the  cobweb  undisturbed,  and  scarcely  stirs  the  lightest 
flower  that  feeds  on  the  dew  it  supplies  ;  yet  it  bears  the  fleets  of 
nations  on  its  wings  around  the  world,  and  ciTishes  the  most  re- 
fractory substances  with  its  weight.  When  in  motion,  its  force 
is  sufficient  to  level  the  most  stately  forests  and  stable  buildings 
with  the  earth — to  raise  the  waters  of  the  ocean  into  ridges  like 
mountains,  and  dash  the  strongest  ships  to  pieces  like  toys.     It 

*  Dr.  Buist,  of  Bombay. 


THE  ATMOSPHERE.  7I 

warms  and  cools  bj  turns  the  eartli  and  the  living  creatures  that 
inhabit  it.  It  draws  up  vapors  from  the  sea  and  land,  retains 
tlicm  dissolved  in  itself,  or  suspended  in  cisterns  of  clouds,  and 
throws  them  down  again  as  rain  or  dew  when  they  are  required. 
It  bends  the  rays  of  the  sun  from  their  path,  to  give  us  the  twi- 
light of  evening  and  of  dawn ;  it  disperses  and  refracts  their  va- 
rious tints  to  beautify  the  approach  and  the  retreat  of  the  orb  of 
day.  But  for  the  atmosphere,  sunshine  would  burst  on  us  and 
fail  us  at  once,  and  at  once  remove  us  from  midnight  darkness  to 
the  blaze  of  noon.  Wc  should  have  no  twilight  to  soften  and 
beautify  the  lan^lscape ;  no  clouds  to  shade  us  from  the  scorching 
heat,  but  the  bald  eartli,  as  it  revolved  on  its  axis,  would  turn  its 
tanned  and  weakened  front  to  the  full  and  unmitigated  rays  of 
the  lord  of  day.  It  affords  the  gas  which  vivifies  and  warms  our 
frames,  and  receives  into  itself  that  which  has  been  polluted  by 
use,  and  is  thrown  off  as  noxious.  It  feeds  the  flame  of  life  ex- 
actly as  it  does  that  of  the  fire — it  is  in  both  cases  consumed,  and 
affords  the  food  of  consumption — in  both  cases  it  becomes  com- 
bined with  charcoal,  which  requires  it  for  combustion,  and  is  re- 
moved by  it  when  this  is  over." 

114.  "It  is  only  the  girdling  encircling  air,"  says  another  phi- 
losopher,* "that  flows  above  and  around  all,  that  makes  the  whole 
world  kin.  The  carbonic  acid  with  wdiich  to-day  our  breathing 
fills  the  air,  to-morrow  seeks  its  way  round  the  world.  The  date- 
trees  that  grow  round  the  falls  of  the  Nile  will  drink  it  in  by  their 
leaves ;  the  cedars  of  Lebanon  will  take  of  it  to  add  to  their  stat- 
ure ;  the  cocoa-nuts  of  Tahiti  will  grow  rapidly  upon  it,  and  the 
palms  and  bananas  of  Japan  will  change  it  into  flowers.  The 
oxygen  we  are  breathing  was  distilled  for  us  some  short  time  ago 
by  the  magnolias  of  the  Susquehanna,  and  the  great  trees  that 
skirt  the  Orinoco  and  the  Amazon — the  giant  rhododendrons  of 
the  Himalayas  contributed  to  it,  and  the  roses  and  myrtles  of 
Cashmere,  the  cinnamon-tree  of  Ceylon,  and  the  forest  older  than 
the  flood,  buried  deep  in  the  heart  of  Africa,  far  behind  the  JMount- 
ains  of  the  Moon.  The  rain  we  see  descendins;  was  thawed  for 
us  out  of  the  icebergs  which  have  watched  the  polar  star  for  ages, 

*  Vide  North  British  Review. 


72  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

and  the  lotus  lilies  have  soaked  up  from  the  Nile,  and  exhaled  as 
vapor,  snows  that  rested  on  the  summits  of  the  Alps." 

115.  "The  atmosphere,"  continues  Maun,  "which  forms  the 
outer  surface  of  the  hahitable  Tj^orld,  is  a  vast  reservoir,  into  which 
the  supply  of  food  designed  for  living  creatures  is  thrown ;  or,  in 
one  word,  it  is  itself  the  food,  in  its  simple  form,  of  all  living  crea- 
tures. The  animal  grinds  down  the  fibre  and  the  tissue  of  the 
plant,  or  the  nutritious  store  that  has  been  laid  up  within  its  cells, 
and  converts  these  into  the  substance  of  which  its  own  organs  are 
composed.  The  plant  acquires  the  organs  and  nutritious  store 
thus  yielded  up  as  food  to  the  animal,  from  the  invulnerable  air 
surrounding  it." 

116.  "But  animals  are  furnished  with  the  means  of  locomotion 
and  of  seizure — they  can  approach  their  food,  and  lay  hold  of  and 
swallow  it ;  plants  must  wait  till  their  food  comes  to  them.  No 
solid  particles  find  access  to  their  frames  ;  the  restless  ambient 
air  which  rushes  past  them  loaded  with  the  carbon,  the  hydrogen, 
the  oxygen,  the  water — every  thing  they  need  in  the  shape  of 
supplies,  is  constantly  at  hand  to  minister  to  their  wants,  not  only 
to  afford  them  food  in  due  season,  but  in  the  shape  and  fashion  in 
which  alone  it  can  avail  them." 

117.  There  is  no  employment  more  ennobKng  to  man  and  his 
intellect  than  to  trace  the  evidences  of  design  and  purpose  in  the 
Creator,  which  are  visible  in  many  parts  of  the  creation.  Hence, 
to  the  right-minded  mariner,  and  to  him  who  studies  the  physical 
relations  of  earth,  sea,  and  air,  the  atmosphere  is  something  more 
than  a  shoreless  ocean,  at  the  bottom  of  which  he  creeps  along. 
It  is  an  envelope  or  covering  for  the  dispersion  of  light  and  heat 
over  the  surface  of  the  earth ;  it  is  a  sewer  into  Avhich,  with  every 
breath  we  draw,  we  cast  vast  quantities  of  dead  animal  matter ; 
it  is  a  laboratory  for  purification,  in  which  that  matter  is  recom- 
pounded,  and  Avrought  again  into  wholesome,  and  healthful  shaj^es; 
it  is  a  machine  (§  112)  for  pumping  up  all  the  rivers  from  the  sea, 
and  conveying  the  waters  for  their  fountains  on  the  ocean  to  their 
sources  in  the  mountains ;  it  is  an  inexhaustible  magazine,  mar- 
velously  adapted  for  many  benign  and  beneficent  purjDOses. 

lis.  Upon  the  proper  working  of  this  machine  depends  the 


THE  ATMOSPHERE.  •  73 

well-being  of  every  plant  and  animal  that  inhabits  the  earth;  there- 
fore the  management  of  it,  its  movements,  and  the  performance 
of  its  offices,  can  not  be  left  to  chance.  They  are,  we  may  rely 
upon  it,  guided  by  laws  that  make  all  parts,  functions,  and  move- 
ments of  the  machinery  as  obedient  to  order  and  as  harmonious 
as  are  the  planets  in  their  orbits. 

119.  An  examination  into  the  economy  of  the  universe  will  be 
sufficient  to  satisfy  the  well-balanced  minds  of  observant  men 
that  the  laws  which  govern  the  atmosphere  and  the  laws  which 
govern  the  ocean  (§  76)  are  laws  which  were  put  in  force  by  the 
Creator  when  the  foundations  of  the  earth  were  laid,  and  that 
therefore  they  are  laws  of  order ;  else,  why  should  the  Gulf 
Stream,  for  instance,  be  always  where  it  is,  and  running  from  the 
Gulf  of  Mexico,  and  not  somewhere  else,  and  sometimes  running 
into  it?  Why  should  there  be  a  perpetual  drought  in  one  part 
of  the  world,  and  continual  showers  in  another  ?  Or  why  should 
the  winds  and  "  waves  of  the  sea  ever  clap  their  hands  with  joy," 
or  obey  the  voice  of  rebuke  ? 

120.  To  one  who  looks  abroad  to  contemplate  the  agents  of  na- 
ture, as  he  sees  them  at  work  upon  our  planet,  no  expression  ut- 
tered nor  act  performed  by  them  is  without  meaning.  By  such 
an  one,  the  wind  and  rain,  the  vapor  and  the  cloud,  the  tide,  the 
current,  the  saltness,  and  depth,  and  warmth,  and  color  of  the  sea, 
the  shade  of  the  sky,  the  temperature  of  the  air,  the  tint  and  shape 
of  the  clouds,  the  height  of  the  tree  on  the  shore,  the  size  of  its 
leaves,  the  brilliancy  of  its  flowers — each  and  all  may  be  regard- 
ed as  the  exponent  of  certain  physical  combinations,  and  therefore 
as  the  expression  in  which  JSTature  chooses  to  announce  her  own 
doings,  or,  if  we  please,  as  the  language  in  which  she  writes  down 
or  chooses  to  make  known  her  own  laws.  To  understand  that 
language  and  to  interpret  aright  those  laws  is  the  object  of  the 
undertaking  which  we  now  have  in  hand.  No  fact  gathered  in 
such  a  field  as  the  one  before  us  can  therefore  come  amiss  to 
those  who  tread  the  walks  of  inductive  philosophy  ;  for,  in  the 
hand-book  of  nature,  every  such  fact  is  a  syllable ;  and  it  is  by 
patiently  collecting  fact  after  fact,  and  by  joining  together  syllable 
after  syllable,  that  we  may  finally  seek  to  read  aright  from  the 


74        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

great  volume  wliicli  the  mariner  at  sea  as  well  as  the  philosopher 
on  the  mountain  each  sees  spread  out  before  him. 

121.  Op  its  circulation. — We  have  seen  (§  31)  that  there 
are  constant  currents  in  the  ocean ;  we  shall  now  see  that  there 
are  also  regular  currents  in  the' atmosphere. 

122.  From  the  parallel  of  about  30°  north  and  south,  nearly  to 
the  equator,  we  have,  extending  entirely  around  the  earth,  two 
zones  of  perpetual  winds,  viz.,  the  zone  of  northeast  trades  on  this 
side,  and  of  southeast  on  that.  With  slight  interruptions,  they 
blow  perpetually,  and  are  as  steady  and  as  constant  as  the  cur- 
rents of  the  ]\Iississippi  E-iver,  always  moving  in  the  same  direc- 
tion (Plate  I.)  except  when  they  are  turned  aside  by  a  desert  here 
and  there  to  blow  as  monsoons,  or  as  land  and  sea  breezes.  As 
these  two  main  currents  of  air  are  constantly  flowing  from  the 
poles  toward  the  equator,  we  are  safe  in  assuming  that  the  air 
which  they  keep  in  motion  must  return  by  some  channel  to  the 
place  toward  the  poles  whence  it  came  in  order  to  supply  the 
trades.  If  this  were  not  so,  these  winds  would  soon  exhaust  the 
Polar  regions  of  atmosphere,  and  pile  it  up  about  the  equator,  and 
then  cease  to  blow  for  the  want  of  air  to  make  more  wind  of. 

123.  This  return  current,  therefore,  must  be  in  the  upper  regions 
of  the  atmosphere,  at  least  until  it  passes  over  those  parallels  be- 
tween which  the  trade-winds  are  always  blowing  on  the  surface. 
The  return  current  must  also  move  in  the  direction  opposite  to 
that  wind  the  place  of  which  it  is  intended  to  supply.  These  di- 
rect and  counter  currents  are  also  made  to  move  in  a  sort  of  spiral 
or  loxodromic  curve,  turning  to  the  west  as  they  go  from  the  poles 
to  the  equator,  and  in  the  opposite  direction  as  they  move  from 
the  equator  toward  the  poles.  This  turning  is  caused  by  the  ro- 
tation of  the  earth  on  its  axis. 

124.  The  earth,  we  know,  moves  from  west  to  east.  Now  if 
we  imagine  a  particle  of  atmosphere  at  the  north  pole,  where  it  is 
at  rest,  to  be  put  in  motion  in  a  straight  line  toward  the  equator, 
wc  can  easily  see  how  this  particle  of  air,  coming  from  the  very 
axis  of  diurnal  rotation,  where  it  did  not  partake  of  the  diurnal 
motion  of  the  earth,  would,  in  consequence  of  its  vis  inertioe,  find, 
as  it  travels  south,  the  earth  slipping  from  under  it,  as  it  were. 


THE  ATMOSPHERE. 


75 


and  thus  it  would  appear  to  be  coming  from  the  northeast  and 
going  toward  the  southwest ;  in  other  words,  it  would  be  a  north- 
east wind. 


DIAGRAM  OF  TllE  WINDS. 

125.  The  better  to  explain,  let  us  take  a  common  teiTestrial 
globe  for  the  illustration.  Bring  the  island  of  Madeira,  or  anj 
other  place  about  the  same  parallel,  under  the  brazen  meridian ; 
put  a  finger  of  the  left  hand  on  the  place;  then,  moving  the  fin- 
ger down  along  the  meridian  to  the  south,  to  represent  the  parti- 
cle of  air,  turn  the  globe  on  its  axis  from  west  to  east,  to  represent 


76  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

the  diurnal  rotation  of  the  earth,  and  when  the  finger  reaches  the 
equator,  stop.  It  will  now  he  seen  that  the  place  on  the  globe 
under  the  finger  is  to  the  southward  and  westward  of  the  place 
from  which  the  finger  started ;  in  other  words,  the  track  of  the 
finger  over  the  surface  of  the  globe,  like  the  track  of  the  particle 
of  air  upon  the  earth,  has  been  from  the  northward  and  eastward. 

126.  On  the  other  hand,  we  can  perceive  how  a  like  particle  of 
atmosphere  that  starts  from  the  equator,  to  take  the  place  of  the 
other  at  the  pole,  would,  as  it  travels  north,  in  consequence  of  its 
vis  ine7'tice,  be  going  toward  the  east  faster  than  the  earth.  It 
would  therefore  appear  to  be  blowing  from  the  southwest,  and 
going  toward  the  northeast,  and  exactly  in  the  opposite  direction 
to  the  other.  Writing  south  for  north,  the  same  takes  place  be- 
tween the  south  pole  and  the  equator. 

127.  Such  is  the  process  which  is  actually  going  on  in  nature ; 
and  if  we  take  the  motions  of  these  two  particles  as  the  type  of 
the  motion  of  all,  we  shall  have  an  illustration  of  the  great  cur- 
rents in  the  air,  the  equator  being  near  one  of  the  nodes,  and  there 
being  at  least  two  systems  of  currents,  an  upper  and  an  under,  be- 
tween it  and  each  pole. 

128.  Ilalley,  in  his  theory  of  the  trade-winds,  pointed  out  the 
key  to  the  explanation  so  far,  of  the  atmospherical  circulation ; 
but,  were  the  explanation  to  rest  here,  a  northeast  trade-wind  ex- 
tending from  the  pole  to  the  equator  would  satisfy  it ;  and  were 
this  so,  we  should  have,  on  the  surface,  no  winds  but  the  north- 
east trade-winds  on  this  side,  and  none  but  southeast  trade-winds 
on  the  other  side,  of  the  equator. 

129.  Let  us  return  now  to  our  northern  particle  (Plate  I.,  p. 
75),  and  follow  it  in  a  round  from  the  north  pole  across  the  equa- 
tor to  the  south  pole,  and  back  again.  Setting  off  from  the  polar 
regions,  this  particle  of  air,  for  some  reason  which  does  not  appear 
to  have  been  very  satisfactorily  explained  by  philosophers,  in- 
stead of  traveling  (§  128)  on  the  surface  all  the  way  from  the  pole 
to  the  equator,  travels  in  the  upper  regions  of  the  atmosphere  un- 
til it  gets  near  the  parallel  of  30°.  Here  it  meets,  also  in  the 
clouds,  the  hypothetical  particle  that  is  coming  from  the  south, 
and  going  north  to  take  its  place. 


THE  ATMOSPHERE.  77 

130.  About  tills  parallel  of  30^  north,  then,  these  two  particles 
press  against  each  other  with  the  whole  amount  of  their  motive 
power,  and  produce  a  calm  and  an  accumulation  of  atmosphere : 
this  accumulation  is  sufficient  to  balance  the  pressure  of  the  two 
winds  from  the  north  and  south. 

131.  From  under  this  bank  of  calms,  which  seamen  call  the 
"horse  latitudes"  (I  have  called  them  the  calms  of  Cancer),  two 
surface  currents  of  wind  are  ejected ;  one  toward  the  equator,  as 
the  northeast  trades,  the  other  toward  the  pole,  as  the  southwest 
passage-winds. 

132.  These  winds  come  out  at  the  lower  surface  of  the  calm 
region,  and  consequently  the  place  of  the  air  borne  away  in  this 
manner  must  be  supplied,  we  may  infer,  by  downward  currents 
from  the  superincumbent  air  of  the  calm  region.  Like  the  case 
of  a  vessel  of  water  which  has  two  streams  from  opposite  direc- 
tions running  in  at  the  top,  and  two  of  equal  capacity  dis- 
charging in  opposite  directions  at  the  bottom,  the  motion  of  the 
water  would  be  downward,  so  is  the  motion  of  the  air  in  this 
calm  zone. 

133.  The  barometer,  in  this  calm  region,  is  said  to  stand  high- 
er than  it  does  either  to  the  north  or  to  the  south  of  it ;  and  this 
is  another  proof  as  to  the  banking  up  here  of  the  atmosphere,  and 
pressure  from  its  downward  motion.  We. can  understand  why 
there  should  be  an  uprising  of  the  air  which  the  two  systems  of 
trade-winds  pour  into  the  equatorial  calms.  But  w^hen  this  air 
commences  to  flow  toward  the  poles  as  an  upper  current,  we  can 
not  understand  why  it  should  not  continue  gradually  to  descend 
and  turn  back  (§  144)  all  the  way  from  the  equator  to  the  poles, 
nor  as  far  as  investigation  has  gone,  has  any  explanation  been 
suggested  for  the  calm  belts  of  the  tropics ;  nor  can  we  tell  why 
the  upper  currents  should  meet  "at  one  parallel  in  preference  to 
another.     But  the  fact  of  a  meeting  and  a  preference  is  certain. 

134.  Following  our  imaginary  particle  of  air,  however,  from  the 
north  across  this  calm  belt  of  Cancer,  we  now  feel  it  moving  on 
the  surface  of  the  earth  as  the  northeast  trade- wind ;  and  as  such 
it  continues,  till  it  arrives  near  the  equator,  where  it  meets  a  like 
hypothetical  particle,  which,  starting  from  the  south  at  the  same 


78        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

time  the  other  started  from  the  north  pole,  has  blown  as  the  south- 
east trade-wind. 

135.  Here,  at  this  equatorial  place  of  meeting,  there  is  another 
conflict  of  winds  and  another  calm  region,  for  a  northeast  and 
southeast  wind  can  not  blow  at  the  same  time  in  the  same  place. 
The  two  particles  have  been  put  in  motion  by  the  same  power ; 
they  meet  with  equal  force  ;  and,  therefore,  at  their  place  of  meet- 
ing, are  stopped  in  their  course.  Here,  therefore,  there  is  a  calm 
belt. 

136.  Warmed  now  by  the  heat  of  the  sun,  and  pressed  on  each 
side  by  the  whole  force  of  the  northeast  and  southeast  trades,  these 
two  hypothetical  particles,  taken  as  the  type  of  the  whole,  cease  to 
move  onward  and  ascend.  This  operation  is  the  reverse  of  that 
which  took  place  at  the  meeting  (§  130)  near  the  parallel  of  30°. 

137.  This  imaginary  particle  then,  having  ascended  to  the  up- 
per regions  of  the  atmosphere  again,  travels  there  counter  to  the 
southeast  trades,  until  it  meets,  near  the  calm  belt  of  Capricorn, 
another  particle  from  the  south  pole ;  here  there  is  a  descent  as 
before  (§  131) ;  it  then  (§126)  flows  on  toward  the  south  pole  as 
a  surface  wind  from  the  northwest. 

138.  Entering  the  polar  regions  obliquely,  it  is  pressed  upon  by 
similar  particles  flowing  in  oblique  currents  across  every  meridian ; 
and  here  again  is  a  calm  place  or  node ;  for,  as  our  imaginary  par- 
ticle approaches  the  parallels  near  the  polar  calms  more  and  more 
obliquely,  it,  with  all  the  rest,  is  whirled  about  the  pole  in  a  con- 
tinued circular  gale ;  finally,  reaching  the  vortex  or  the  calm  place, 
it  is  carried  upward  to  the  regions  of  atmosphere  above,  whence 
it  commences  again  its  circuit  to  the  north  as  an  upper  current, 
as  far  as  the  calm  belt  of  Capricorn;  here  it  encounters  (§  137)  its 
fellow  from  the  north  (§  126) ;  they  stop,  descend,  and  flow  out  as 
surface  currents  (§  132),  the  one  with  which  the  imagination  is 
traveling,  to  the  equatorial  calm  as  the  southeast  trade-wind ;  here 
(§  135)  it  ascends,  traveling  thence  to  the  calm  belt  of  Cancer  as 
an  upper  current  counter  to  the  northeast  trades.  Here  (§  130 
and  129)  it  ceases  to  be  an  upper  current,  but,  descending  (§  131), 
travels  on  with  the  southwest  passage-winds  toward  the  pole. 

139.  Now  the  course  we  have  imagined  an  atom  of  air  to  take 


THE  ATMOSPHERE.  79 

is  this  (Plate  I.) :  an  ascent  in  a  place  of  calms  about  the  north 
pole  at  P ;  an  efflux  thence  as  an  upper  current  (§  129)  until  it 
meets  G  (also  an  upper  current)  over  the  calms  of  Cancer.  Here 
(§  130)  there  is  supposed  to  be  a  descent,  as  shown  by  the  arrows 
along  the  wavy  lines  which  envelop  the  circle.  This  upper  cur- 
rent from  the  pole  (§  124)  now  becomes  the  northeast  trade- wind, 
B  (§  134),  on  the  surface,  until  it  meets  the  southeast  trades  in 
the  equatorial  calms,  when  it  ascends  and  travels  as  C  with  the 
upper  current  to  the  calms  of  Capricorn,  then  as  D  with  the  pre- 
vailing northwest  surface  current  to  the  south  pole,  thence  up 
with  the  arrow  P,  and  around  with  the  hands  of  a  watch,  and 
back,  as  indicated  by  the  arrows  along  E,  F,  G,  and  H. 

140.  The  Bible  frequently  makes  allusions  to  the  laws  of  na- 
ture, their  operation  and  effects.  But  such  allusions  are  often  so 
wrapped  in  the  folds  of  the  peculiar  and  graceful  drapery  with 
which  its  language  is  occasionally  clothed,  that  the  meaning, 
though  peeping  out  from  its  thin  covering  all  the  while,  yet  lies 
in  some  sense  concealed,  until  the  lights  and  revelations  of  science 
are  thrown  upon  it ;  then  it  bursts  out  and  strikes  us  with  ex- 
quisite force  and  beauty. 

141.  As  our  knowledge  of  nature  and  her  laws  has  increased, 
so  has  our  understanding  of  many  passages  in  the  Bible  been  im- 
proved. The  Psalmist  called  the  earth  "the  round  world;"  yet 
for  ages  it  was  the  most  damnable  heresy  for  Christian  men  to  say 
the  world  is  round ;  and,  finally,  sailors  circumnavigated  the  globe, 
proved  the  Bible  to  be  right,  and  saved  Christian  men  of  science 
from  the  stake. 

142.  "  Canst  thou  bind  the  sweet  influences  of  the  Pleiades  ?*' 
Astronomers  of  the  present  day,  if  they  have  not  answered  this 

question,  have  thrown  so  much  light  upon  it  as  to  show  that,  if 
ever  it  be  answered  by  man,  he  must  consult  the  science  of  astron- 
omy. It  has  been  recently  all  but  proved,  that  the  earth  and  sun, 
with  their  splendid  retinue  of  comets,  satellites,  and  planets,  are 
all  in  motion  around  some  point  or  centre  of  attraction  inconceiv- 
ably remote,  and  that  that  point  is  in  the  direction  of  the  star  Al- 
cyon,  one  of  the  Pleiades !  Who  but  the  astronomer,  then,  could 
tell  their  "  sweet  influences  ?" 


80        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

143.  And  as  for  the  general  system  of  atmospherical  ch'ciila- 
tion  which  I  have  been  so  long  endeavoring  to  describe,  the  Bible 
tells  it  all  in  a  single  sentence:  "The  wind  goeth  toward  the 
south,  and  turneth  about  unto  the  north ;  it  whirleth  about  con- 
tinually, and  the  wind  returncth  again  according  to  his  circuits." 
— Eccl.,  i.,  G. 

144.  Of  course,  as  the  surface  winds  H  and  D  (Plate  I.)  ap- 
proach the  poles,  there  must  be  a  sloughing  off,  if  I  may  be  allow- 
ed the  expression,  of  air  from  the  surface  winds,  in  consequence 
of  their  approaching  the  poles.  For  as  they  near  the  poles,  the 
parallels  become  smaller  and  smaller,  and  the  surface  current  must 
either  extend  much  higher  up,  and  blow  with  greater  rapidity  as 
it  approaches  the  poles,  or  else  a  part  of  it  must  be  sloughed  off 
above,  and  so  turn  back  before  reaching  the  calms  about  the  poles. 
The  latter  is  probably  the  case. 

145.  Our  investiii'ations  show  that  the  southeast  trade-wind  re- 

o 

g-ion  is  much  larger  than  the  northeast  (I  speak  now  of  its  ex- 
tent over  the  Atlantic  Ocean  only) ;  that  the  southeast  trades  are 
the  fresher,  and  that  they  often  push  themselves  up  to  10°  or  15^ 
of  north  latitude ;  Avhereas  the  northeast  trade-wind  seldom  gets 
south  of  the  equator. 

146.  The  peculiar  clouds  of  the  trade-winds  are  formed  between 
the  upper  and  lower  currents  of  air.  They  are  probably  formed 
of  vapor  condensed  from  the  upper  current,  and  evaporated  as  it 
descends  by  the  lower  and  dry  current  from  the  poles.  It  is  the 
same  phenomenon  up  there  which  is  so  often  observed  here  below ; 
when  a  cool  and  dry  current  of  air  meets  a  warm  and  wet  one,  an 
evolution  of  vapor  or  fog  ensues. 

147.  We  now  see  the  general  course  of  the  "wind  in  his  cir- 
cuits," as  we  see  the  general  course  of  the  water  in  a  river.  There 
are  many  abrading  surfaces,  irregularities,  &c.,  which  produce  a 
thousand  eddies  in  the  main  stream ;  yet,  nevertheless,  the  gen- 
eral direction  of  the  whole  is  not  disturbed  nor  aftccted  by  those 
counter  currents ;  so  with  the  atmosphere  and  the  variable  winds 
which  we  find  here  in  this  latitude. 

148.  Have  I  not,  therefore,  very  good  grounds  for  the  opinion 
(§  118)  that  the  "wind  in  his  circuits,"  though  apparently  to  us 


THE  ATMOSPHERE.  31 

never  so  wayward,  is  as  obedient  to  law  and  as  subservient  to  or- 
der as  were  the  morning  stars  when  they  "  sang  together?" 

149.  There  are  at  least  two  forces  coneerned  in  driving  the 
wind  through  its  circuits.  We  have  seen  (§  124)  whence  that 
force  is  derived  which  gives  easting  to  the  winds  as  they  approach 
^he  equator,  and  westing  as  they  approach  the  poles,  and  allusion, 
without  explanation,  has  been  made  (§  136)  to  the  source  whence 
they  derive  their  northing  and  their  southing.  The  trade-winds 
are  caused,  it  is  said,  by  the  inter-tropical  heat  of  the  sun,  which, 
expanding  the  air,  causes  it  to  rise  up  near  the  equator ;  it  then 
flows  off  in  the  upper  currents  north  and  south,  and  there  is  a  rush 
of  air  at  the  surface  both  from  the  north  and  the  south  to  restore 
the  equilibrium — hence  the  trade-winds.  But  to  the  north  side 
of  the  trade-wind  belt  in  the  northern,  and  on  the  south  side  in 
the  southern  hemisphere,  the  prevailing  direction  of  the  winds  is 
not  toward  the  source  of  heat  about  the  equator,  but  exactly  in 
the  opposite  direction.  In  the  extra-tropical  region  of  each  hem- 
isphere the  prevailing  winds  blow  from  the  equator  toward  the 
poles.  It  therefore  at  first  appears  paradoxical  to  say  that  heat 
makes  the  easterly  winds  of  the  torrid  zone  blow  toward  the  equa- 
tor, and  the  westerly  winds  of  the  temperate  zones  to  blow  toward 
the  poles.     Let  us  illustrate : 

150.  The  jprhmiin  mobile  of  the  extra-tropical  winds  toward 
the  equator  is,  as  just  intimated,  generally  ascribed  to  heat,  and 
in  this  wise,  viz. :  Suppose,  for  the  moment,  the  earth  to  have  no 
diurnal  rotation  ;  that  it  is  at  rest ;  that  the  rays  of  the  sun  have 
been  cut  off  from  it ;  that  the  atmosphere  has  assumed  a  mean 
uniformity  of  temperature,  the  thermometer  at  the  equator  and  the 
thermometer  at  the  poles  giving  the  same  reading ;  that  the  winds 
are  still,  and  that  the  whole  aerial  ocean  is  in  equilibrium  and  at 
rest.  Now  imagine  the  screen  which  is  supposed  to  have  shut 
off  the  influence  of  the  sun  to  be  removed,  and  the  whole  atmos- 
phere to  assume  the  various  temperatures  in  the  various  parts  of 
the  world  that  it  actually  has  at  this  moment,  what  would  take 
place,  supposing  the  uniform  temperature  to  be  a  mean  between 
that  at  the  equator  and  that  at  the  poles  ?  Why,  this  would  take 
place :  a  swelling  up  of  the  atmosphere  about  the  equator  by  the 


82  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

expansive  force  of  inter-tropical  lieat,  and  a  contraction  of  it  about 
the  poles  in  consequence  of  the  cold.  These  two  forces,  consid- 
ering them  under  their  most  obvious  effects,  would  disturb  the 
supposed  atmospherical  equilibrium  by  altering  the  level  of  the 
great  aerial  ocean  ;  the  expansive  force  of  heat  elevating  it  about 
the  equator,  and  the  contracting  powers  of  cold  depressing  it  about 
tlie  poles.  And  forthwith  two  systems  of  winds  v/ould  commence 
to  blow,  viz.,  one  in  the  upper  regions  from  the  equator  toward 
the  poles,  and  as  this  warm  and  expanded  air  should  flow  toward 
either  poJe,  seeking  its  level,  a  wind  would  blow  on  the  surface 
from  either  pole  to  restore  the  air  to  the  equator  which  the  upper 
current  had  carried  off. 

151.  These  two  w^inds  would  blow  due  north  and  south ;  the 
effects  of  heat  at  the  equator,  and  cold  at  the  poles,  would  cause 
them  so  to  do.  Now  suppose  the  earth  to  commence  its  diurnal 
rotation ;  then,  instead  of  having  these  winds  north  and  south 
winds,  they  will,  for  reasons  already  explained  (§  124),  approach 
the  equator  on  both  sides  with  easting  in  them,  and  each  pole 
with  westing. 

152.  The  circumference  of  the  earth  measured  on  the  parallel 
of  60°  is  only  half  what  it  is  when  measured  on  the  equator. 
Therefore,  supposing  velocity  to  be  the  same,  only  half  the  vol- 
ume of  atmosphere  (§  149)  that  sets  off  from  the  equator  as  an 
upper  current  toward  the  poles  can  cross  the  parallel  of  60°  north 
or  south.  The  other  moiety  has  been  gradually  drawn  in  and 
carried  back  (§  144)  by  the  current  which  is  moving  in  the  oppo- 
site direction. 

153.  Such,  and  such  only,  would  be  the  extent  of  the  power 
of  the  sun  to  create  a  polar  and  equatorial  flow  of  air,  were  its 
power  confined  simply  to  a  change  of  level.  But  the  atmosphere 
has  been  invested  with  another  property  which  increases  its  mo- 
bility, and  gives  the  heat  of  the  sun  still  more  j)ower  to  put  it  in 
motion,  and  it  is  this :  as  heat  changes  the  atmospherical  level,  it 
changes  also  the  specific  gravity  of  the  air  acted  upon.  If,  there- 
fore, the  level  of  the  great  aerial  ocean  were  undisturbed  by  the 
sun's  rays,  and  if  the  air  were  adapted  to  a  change  of  specific  grav- 
ity alone,  without  any  change  in  volume,  this  quality  would  also 


THE  ATMOSPHERE.  g3 

be  the  source  of  at  least  two  systems  of  currents  in  the  air,  viz., 
an  upper  and  a  lower.  The  two  agents  combined,  viz.,  that  which 
changes  level  or  volume,  and  that  which  changes  specific  gravity, 
give  us  the  general  currents  under  consideration.  Hence  we  say 
that  the  ]jrhmiin  raohile  of  the  air  is  derived  from  change  of  spe- 
cific gravity  induced  by  the  freezing  temperature  of  the  polar  re- 
gions, as  well  as  from  change  of  specific  gravity  due  the  expand- 
ing force  of  the  sun's  rays  within  the  tropics. 

154.  Therefore,  fairly  to  appreciate  the  extent  of  the  influence 
due  the  heat  of  the  sun  in  causing  the  winds,  it  should  be  recol- 
lected that  we  may  with  as  much  reason  ascribe  to  the  inter-trop- 
ical heat  of  the  sun  the  northwest  winds,  which  are  the  prevailino- 
winds  of  the  extra-tropical  regions  of  the  southern  hemisphere,  or 
the  southwes-t  winds,  which  are  the  prevailing  winds  of  the  extra- 
tropical  regions  of  the  northern  hemisphere,  as  we  may  the  trade- 
winds,  which  blow  in  the  opposite  directions.  Paradoxical,  there- 
fore, as  it  seems  for  us  to  say  that  the  heat  of  the  sun  causes  the 
winds  between  the  parallels  of  25°  or  30°  north  and  south  to 
blow  toward  the  equator,  and  that  it  also  causes  the  prevaihng 
winds  on  the  polar  sides  of  these  same  parallels  to  blow  toward 
the  poles,  yet  the  paradox  ceases  when  we  come  to  recollect  that 
by  the  process  of  equatorial  heating  and  polar  cooling  which  is 
going  on  in  the  atmosphere,  the  specific  gravity  of  the  air  is 
changed  as  well  as  its  level.  Nevertheless,  as  Halley  said,  in  his 
paper  read  before  the  Eoyal  Society  in  London  in  1686,  and  as 
we  also  have  said  (§  133),  "it  is  likewise  very  hard  to  conceive 
why  the  limits  of  the  trade-wind  should  be  fixed  about  the  paral- 
lel of  latitude  30°  all  around  the  globe,  and  that  they  should  so 
seldom  exceed  or  fall  short  of  those  bounds." 

155.  Operated  upon  by  the  equilibrating  tendency  of  the  at- 
mosphere and  by  diurnal  rotation,  the  wind  approaches  the  north 
pole,  for  example,  by  a  series  of  spirals  from  the  southwest.  If 
we  draw  a  circle  about  this  pole  on  a  common  terrestrial  globe, 
and  intersect  it  by  spirals  to  represent  the  direction  of  the  wind, 
we  shall  see  that  the  wind  enters  all  parts  of  this  cu'cle  from  the 
southwest,  and  that,  consequently,  there  should  be  about  the  poles 

a  disc  or  circular  space  of  calms,  in  which  the  air  ceases  to  move 

F 


84  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

forward  as  wind,  and  ascends  as  in  a  calm ;  about  this  calm  disc, 
therefore,  there  should  be  a  whirl,  in  which  the  ascending  column 
of  air  revolves  from  right  to  left,  or  against  the  hands  of  a  watch. 
At  the  south  pole  the  winds  come  from  the  northwest  (§  137),  and 
consequently  there  they  revolve  about  it  loith  the  hands  of  a  Avatch. 
That  this  should  be  so  will  be  obvious  to  any  one  who  will 
look  at  the  arrows  on  the  polar  sides  of  the  calms  of  Cancer  and 
Capricorn  (Plate  I.,  p.  75).  These  arrows  are  intended  to  repre- 
sent the  prevailing  direction  of  the  wind  at  the  surface  of  the  earth 
on  the  polar  side  of  these  calms. 

156.  It  is  a  sino'ular  coincidence  between  these  two  facts  thus 
deduced,  and  other  facts  which  have  been  observed,  and  which 
have  been  set  forth  by  E-edfield,  E-eid,  Piddington,  and  others, 
viz.,  that  many  of  the  rotary  storms  in  the  northern  hemisphere 
revolve  as  do  the  whirlwinds  about  the  north  pole,  viz.,  from  right 
to  left,  and  that  all  circular  gales  in  the  southern  hemisphere  re- 
volve in  the  opposite  direction,  as  does  the  whud  about  the  south 
pole. 

157.  How  can  there  be  any  connection  between  the  rotary  mo- 
tion of  the  wind  about  the  pole,  and  the  rotary  motion  of  it  in  a 
gale  caused  here  by  local  agents? 

158.  That  there  is  probably  such  a  connection  has  been  sug- 
gested by  other  facts  and  circumstances,  and  perhaps  I  shall  be 
enabled  to  make  myself  clearer  when  we  come  to  treat  of  these 
facts  and  circumstances,  and  to  inquire  farther,  as  at  §  299,  into 
the  relations  between  magnetism  and  the  circulation  of  the  atmos- 
phere ;  for,  although  the  theory  of  heat  satisfies  the  conditions  of 
the  problem,  and  though  heat,  doubtless,  is  one  of  the  chief  agents 
in  keeping  up  the  circulation  of  the  atmosphere,  yet  it  can  be  made 
to  appear  that  it  is  not  the  sole  agent. 

159.  Some  of  its  Meteorological  Agencies. — So  far,  we 
see  how  the  atmosphere  moves ;  but  the  atmosphere,  like  every 
other  department  in  the  economy  of  nature,  has  its  offices  to  per- 
form, and  they  arc  many.  I  have  already  alluded  to  some  of  them ; 
but  I  only  propose,  at  this  time,  to  consider  some  of  the  meteoro- 
logical agencies  at  sea,  which,  in  the  grand  design  of  creation,  have 
probably  been  assigned  to  this  wonderful  machine. 


THE  ATMOSPHERE.  85 

160.  To  distribute  moisture  over  the  surface  of  the  earth,  and 
to  temper  the  climate  of  different  latitudes,  it  would  seem,  are 
two  great  offices  assigned  by  their  Creator  to  the  ocean  and  the 
air. 

161.  When  the  northeast  and  southeast  trades  meet  and  pro- 
duce the  equatorial  calms  (§  135),  the  air,  by  the  time  it  reaches 
this  calm  belt,  is  heavily  laden  with  moisture,  for  in  each  hemi- 
sphere it  has  traveled  obliquely  over  a  large  space  of  the  ocean. 
It  has  no  room  for  escape  but  in  the  upward  direction  (§  136).  It 
expands  as  it  ascends,  and  becomes  cooler ;  a  portion  cf  its  vapor 
is  thus  condensed,  and  comes  down  in  the  shape  of  rain.  There- 
fore it  is  that,  under  these  calms,  we  have  a  region  of  constant 
precipitation.  Old  sailors  tell  us  of  such  dead  calms  of  long  con- 
tinuance here,  of  such  heavy  and  constant  rains,  that  they  have 
scooped  up  fresh  water  from  the  surface  of  the  sea. 

162.  The  conditions  to  which  this  air  is  exposed  here  under 
the  equator  are  probably  not  such  as  to  cause  it  to  precipitate  all 
the  moisture  that  it  has  taken  up  in  its  long  sweep  across  the 
waters.  Let  us  see  what  becomes  of  the  rest ;  for  jSTature,  in  her 
economy,  permits  nothing  to  be  taken  away  from  the  earth  which 
is  not  to  be  restored  to  it  again  in  some  form,  and  at  some  time 
or  other. 

163.  Consider  the  great  rivers — the  Amazon  and  the  Missis- 
sippi, for  example.  We  see  them  day  after  day,  and  year  after 
year,  discharging  immense  volumes  of  water  into  the  ocean. 

"All  the  rivers  run  into  the  sea,  yet  the  sea  is  not  full." — EccL, 
i,,  7.  Where  do  the  waters  so  discharged  go,  and  where  do  they 
come  from?  They  come  from  their  sources,  you  will  say.  But 
whence  are  their  sources  supplied  ?  for,  unless  what  the  fountain 
sends  forth  be  returned  to  it  again,  it  will  fail  and  be  dry. 

164.  We  see  simply,  in  the  waters  that  are  discharged  by 
these  rivers,  the  amount  by  which  the  precipitation  exceeds  the 
evaporation  throughout  the  whole  extent  of  valley  drained  by 
them  ;  and  by  precipitation  I  mean  the  total  amount  of  water  that 
falls  from,  or  is  deposited  by  the  atmosphere,  whether  as  dew, 
rain,  hail,  or  snow. 

165.  The  springs  of  these  rivers  (§  112)  are  suppHed  from  the 


86  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

rains  of  heaven,  and  these  rains  are  formed  of  vapors  whicli  are 
taken  up  from  the  sea,  that  "it  be  not  full,"  and  carried  up  to  the 
mountains  through  the  air. 

"Note  the  place  whence  the  .rivers  come,  thither  they  return 


again. 


166.  Behold  how  the  waters  of  the  Amazon,  of  the  Mississippi, 
the  St.  Lawrence,  and  all  the  great  rivers  of  America,  Europe,  and 
Asia,  lifted  up  by  the  atmosphere,  and  flowing  in  invisible  streams 
back  through  the  air  to  their  sources  among  the  hills  (§  112),  and 
that  through  channels  so  regular,  certain,  and  well  defined,  that 
the  quantity  thus  conveyed  one  year  with  the  other  is  nearly  the 
same :  for  that  is  the  quantity  which  we  see  running  down  to  the 
ocean  through  these  rivers  ;  and  the  quantity  discharged  annually 
by  each  river  is,  as  far  as  we  can  judge,  nearly  a  constant. 

167.  We  now  begin  to  conceive  what  a  powerful  machine  the 
atmosphere  must  be ;  and,  though  it  is  apparently  so  capricious 
and  wayward  in  its  movements,  here  is  evidence  of  order  and  ar- 
rangement which  we  must  admit,  and  proof  which  we  can  not 
deny,  that  it  performs  this  mighty  office  v/ith  regularity  and  cer- 
tainty, and  is  therefore  as  obedient  to  law  as  is  the  steam-engine 
to  the  will  of  its  builder. 

168.  It,  too,  is  an  engine.  The  South  Seas  themselves,  in  all 
their  vast  inter-tropical  extent,  are  the  boiler  for  it,  and  the  north- 
ern hemisphere  is  its  condenser.  The  mechanical  power  exerted 
by  the  air  and  the  sun  in  lifting  water  from  the  earth,  in  trans- 
porting it  from  one  place  to  another,  and  in  letting  it  down  again, 
is  inconceivably  great.  The  utilitarian  who  compares  the  water- 
power  that  the  Falls  of  Niagara  would  afford  if  applied  to  ma- 
chinery, is  astonished  at  the  number  of  figures  which  are  required 
to  express  its  equivalent  in  horse-power.  Yet  what  is  the  horse- 
power of  the  Niagara,  falling  a  few  steps,  in  comparison  with  the 
horse-power  that  is  required  to  lift  up  as  high  as  the  clouds  and 
let  down  again  all  the  water  that  is  discharged  into  the  sea,  not 
only  by  this  river,  but  by  all  the  other  rivers  in  the  world.  The 
calculation  has  been  made  by  engineers,  and,  according  to  it,  the 
force  for  making  and  lifting  vapor  from  each  area  of  one  acre  that 
is  included  on  the  surface  of  the  earth  is  equal  to  the  power  of  30 


THE  ATMOSPHERE. 


87 


horses,  and  for  the  whole  area  of  the  earth  it  is  800  times  greater 
than  all  the  water-power  in  Europe. 

169.  Where  does  the  va])ov  that  onakes  the  rains  ivhich  feed 
the  7'ive7'S  of  the  northern  hemisphere  come  from  ? 

The  proportion  between  the  land  and  water  in  the  northern 
hemisphere  is  very  different  from  the  proportion  that  obtains  be- 
tween them  in  the  southern.  In  the  northern  hemisphere,  the  land 
and  water  are  nearly  equally  divided.  In  the  southern,  there  is 
several  times  more  water  than  land.  All  the  great  rivers  in  the 
world  are  in  the  northern  hemisphere,  where  there  is  less  ocean  to 
supply  therii.  Whence,  then,  are  their  sources  replenished  ?  Those 
of  the  Amazon  are  supplied  with  rains  from  the  equatorial  calms 
and  trade- winds  of  the  Atlantic.  That  river  runs  east,  its  branch- 
es come  from  the  north  and  south ;  it  is  always  the  rainy  season 
on  one  side  or  the  other  of  it ;  consequently,  it  is  a  river  without 
periodic  stages  of  a  very  marked  character.  It  is  always  near  its 
high-water  mark.  For  one  half  of  the  year  its  northern  tributa- 
ries are  flooded,  and  its  southern  for  the  other  half.  It  discharges 
under  the  line,  and  as  its  tributaries  come  from  both  hemispheres, 
it  can  not  be  said  to  belong  exclusively  to  either.  It  is  supplied 
with  water  made  of  vapor  that  is  taken  up  from  the  Atlantic 
Ocean.  Taking  the  Amazon,  therefore,  out  of  the  count,  the  Hio 
de  la  Plata  is  the  only  great  river  of  the  southern  hemisphere. 
There  is  no  large  river  in  New  Holland.  The  South  Sea  Islands 
give  rise  to  none,  nor  is  there  one  in  South  Africa  entitled  to  be 
called  great  that  we  know  of. 

170.  The  gTcat  rivers  of  North  America  and  North  Africa,  and 
all  the  rivers  of  Europe  and  Asia,  lie  wholly  within  the  northern 
hemisphere.  How  is  it,  then,  considering  that  the  evaporating  sur- 
face lies  mainly  in  the  southern  hemisphere — how  is  it,  I  say,  that 
we  should  have  the  evaporation  to  take  place  in  one  hemisphere 
and  the  condensation  in  the  other  ?  The  total  amount  of  rain 
which  falls  in  the  northern  hemisphere  is  much  greater,  meteorol- 
ogists teU  us,  than  that  which  falls  in  the  southern.  The  annual 
amount  of  rain  in  the  north  temperate  zone  is  half  as  much  again 
as  that  of  the  south  temperate, 

171.  How  is  it,  then,  that  this  vapor  gets,  as  stated  §  170,  from 


88  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

tlie  southern  into  tlie  northern  hemisphere,  and  comes  with  such 
regularity  that  our  rivers  never  go  dry  and  our  springs  fail  not  ? 
It  is  because  of  the  beautiful  operations  and  the  exquisite  com- 
pensati07i  of  this  grand  machine,  the  atmosphere.  It  is  exquis- 
itely and  wonderfully  counterpoised.  Late  in  the  autumn  of  the 
north,  throughout  its  winter,  and  in  early  spring,  the  sun  is  pour- 
ing his  rays  with  the  greatest  intensity  down  upon  the  seas  of  the 
southern  hemisphere,  and  this  powerful  engine  which  we  are  con- 
templating is  pumping  up  the  water  there  (§  169)  for  our  rivers 
with  the  greatest  activity.  At  this  time,  the  mean  temperature 
of  the  entire  southern  hemisphere  is  said  to  be  about  10°  higher 
than  the  northern. 

172.  The  heat  which  this  heavy  evaporation  absorbs  becomes 
latent,  and,  with  the  moisture,  is  carried  through  the  upper  re- 
gions of  the  atmosphere  until  it  reaches  our  climates.  Here  the 
vapor  is  formed  into  clouds,  condensed,  and  precipitated.  The 
heat  which  held  this  water  in  the  state  of  vapor  is  set  free,  it  be- 
comes sensible  heat,  and  it  is  that  which  contributes  so  much  to 
temper  our  winter  climate.  It  clouds  up  in  winter,  turns  warm, 
and  we  say  we  are  going  to  have  falling  weather.  That  is  be- 
cause the  process  of  condensation  has  already  commenced,  though 
no  rain  or  snow  may  have  fallen :  thus  we  feel  this  southern  heat, 
that  has  been  collected  from  the  rays  of  the  sun  by  the  sea,  been 
bottled  away  by  the  winds  in  the  clouds  of  a  southern  summer, 
and  set  free  in  the  process  of  condensation  in  our  northern  winter. 

173.  If  the  Plate  at  page  75  fairly  represent  the  course  of  the 
winds,  the  southeast  trade-winds  would  enter  the  northern  hemi- 
sphere, and,  as  an  upper  current,  bear  into  it  all  their  moisture, 
except  that  which  is  precipitated  in  the  region  of  equatorial  calms. 

174.  The  South  Seas,  then,  according  to  §  168,  should  supply 
mainly  the  water  for  this  engine,  while  the  northern  hemisphere 
condenses  it ;  we  should,  therefore,  have  more  rain  in  the  northern 
hemisphere.  The  rivers  tell  us  that  we  have — at  least  on  the  land : 
for  the  great  water-courses  of  the  globe,  and  half  the  fresh  water 
in  the  world,  are  found  on  our  side  of  the  equator.  This  fact 
alone  is  strongly  corroborative  of  this  hypothesis. 

175.  The  rain  gauge  tells  us  also  the  same  story.     The  yearly 


THE  ATMOSPHERE.  39 

average  of  rain  in  tlie  north  temperate  zone  is,  according  to  John- 
ston, thirty-seven  inches.  He  gives  but  twenty-six  in  the  south 
temperate.  The  observations  of  mariners  are  also  corroborative 
of  the  same.  Log-books,  containing  altogether  the  records  for  up- 
ward of  260,000  days  in  the  Atlantic  Ocean  north  and  south 
(Plate  XIII.),  have  been  carefully  examined  for  the  purpose  of 
ascertaining,  for  comparison,  the  number  of  calms,  rains,  and  gales 
therein  recorded  for  each  hemisphere.  Proportionally  the  number 
of  each  is  given  as  decidedly  greater  for  the  north  than  it  is  for 
the  south.  The  result  of  this  examination  is  very  instructive,  for 
it  shows  the  status  of  the  atmosphere  to  be  much  more  unstable 
in  the  northern  hemisphere,  with  its  excess  of  land,  than  in  the 
southern,  with  its  excess  of  water.  Rains,  and  fogs,  and  thunder, 
and  calms,  and  storms,  all  occur  much  more  frequently,  and  are 
more  irregular  also  as  to  the  time  and  place  of  their  occurrence  on 
this  side,  than  they  are  on  the  other  side  of  the  equator. 

176.  Moisture  is  never  extracted  from  the  air  by  subjecting  it 
from  a  low  to  a  higher  temperature,  but  the  reverse.  Thus  all 
the  air  which  comes  loaded  with  moisture  from  the  other  hemi- 
sphere, and  is  borne  into  this  with  the  southeast  trade-winds,  trav- 
els in  the  upper  regions  of  the  atmosphere  (§  130)  until  it  reaches 
the  calms  of  Cancer ;  here  it  becomes  the  surface  wind  that  pre- 
vails from  the  southward  and  westward.  As  it  goes  north  it 
grows  cooler,  and  the  process  of  condensation  commences. 

177.  We  may  now  liken  it  to  the  wet  sponge,  and  the  decrease 
of  temperature  to  the  hand  that  squeezes  that  sponge.  Finally 
reaching  the  cold  latitudes,  all  the  moisture  that  a  dew-point  of 
zero,  and  even  far  below,  can  extract,  is  wrung  from  it ;  and  this 
air  then  commences  "  to  return  according  to  his  circuits"  as  dry 
atmosphere.  And  here  we  can  quote  Scripture  again :  "  The 
north  wind  driveth  away  rain.""  This  is  a  meteorological  fact  of 
high  authority  and  great  importance  in  the  study  of  the  circula- 
tion of  the  atmosphere. 

178.  By  reasoning  in  this  manner  and  from  such  facts,  we  are 
led  to  the  conclusion  that  our  rivers  are  supplied  with  their  waters 
principally  from  the  trade-wind  regions — the  extra-tropical  north- 
ern rivers  from  the  southern  trades,  and  the  extra-tropical  south- 


90  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

ern  rivers  from  the  northern  trade-winds,  for  the  trade-winds  are 
the  evaporating  winds. 

179.  Taking  for  our  guide  such  faint  glimmerings  of  light  as 
we  can  catch  from  these  facts,  and  supposing  these  views  to  be 
correct,  then  the  saltest  portion  o^  the  sea  should  he  in  the  trade- 
wind  regions,  where  the  water  for  all  the  rivers  is  evaporated  ;  and 
there  the  saltest  portions  are  found.  There,  too,  the  rains  fall  less 
frequently  (Plate  XIII.). 

180.  Dr.  Euschenberger,  of  the  Navy,  on  his  last  voyage  to  In- 
dia, was  kind  enough  to  conduct  a  series  of  observations  on  the 
specific  gravity  of  sea  water.  In  about  the  parallel  of  17°  north 
and  south— midway  of  the  trade- wind  regions — he  found  the  heav- 
iest water.  Though  so  warm,  the  water  there  was  heavier  than 
the  cold  water  to  the  south  of  the  Cape  of  Good  Hope.  Lieuten- 
ant D.  D.  Porter,  in  the  steam-ship  Golden  x4ge,  found  the  heav- 
iest water  about  the  parallels  of  20°  north  and  17°  south. 

181.  In  summing  up  the  evidence  in  favor  of  this  view  of  the 
general  system  of  atmospherical  circulation,  it  remains  to  be  shown 
how  it  is,  if  the  view  be  correct,  there  should  be  smaller  rivers  and 
less  rain  in  the  southern  hemisphere.  The  winds  that  are  to  blow 
as  the  northeast  trade-winds,  returning  from  the  polar  regions, 
where  the  moisture  (§  176)  has  been  compressed  out  of  them,  re- 
main, as  we  have  seen,  dry  winds  until  they  cross  the  calm  zone 
of  Cancer,  and  are  felt  on  the  surface  as  the  !northeast  trades. 
About  two  thirds  of  them  only  can  then  blov/  over  the  ocean ;  the 
rest  blow  over  the  land,  over  Asia,  Africa,  and  North  America, 
where  there  is  but  comparatively  a  small  portion  of  evaporating 
surface  exposed  to  their  action. 

182.  The  zone  of  the  northeast  trades  extends,  on  an  average, 
from  about  29°  north  to  7°  north.  Now,  if  we  examine  the  globe, 
to  see  how  much  of  this  zone  is  land  and  how  much  water,  we 
shall  find,  commencing  with  China  and  coming  over  Asia,  the 
broad  part  of  Africa,  and  so  on,  across  the  continent  of  America 
to  the  Pacific,  land  enough  to  fill  up,  as  nearly  as  may  be,  just  one 
third  of  it.  This  land,  if  thrown  into  one  body  between  these  par- 
allels, would  make  a  belt  equal  to  120°  of  longitude  by  22°  of  lat- 
itude, and  comprise  an  area  of  about  twelve  and  a  half  millions 


THE  ATMOSPHERE.  9]^ 

of  square  miles,  thus  leaving  an  evaporating  surface  of  albout  twen- 
ty-five millions  of  square  miles  in  the  northern  against  about  sev- 
enty-five millions  in  the  southern  hemisphere. 

183.  According  to  the  hypothesis,  illustrated  by  Plate  I.,  p.  75, 
as  to  the  circulation  of  the  atmosphere,  it  is  these  northeast  trade- 
winds  that  take  up  and  carry  over,  after  they  rise  up  in  the  belt 
of  equatorial  calms,  the  vapors  which  make  the  rains  that  feed  the 
rivers  in  the  extra-tropical  regions  of  the  southern  hemisphere. 

184.  Upon  this  supposition,  then,  two  thirds  only  of  the  north- 
east trade-winds  are  fully  charged  with  moisture,  and  only  two 
thirds  of  the  amount  of  rain  that  falls  in  the  northern  hemisphere 
should  fall  in  the  southern,  and  this  is  just  about  the  proportion 
(§  173)  that  observation  gives. 

185.  In  like  manner,  the  southeast  trade-winds  take  up  the  va- 
pors which  make  our  river's,  and  as  they  prevail  to  a  much  greater 
extent  at  sea,  and  have  exposed  to  their  action  about  three  times 
as  much  ocean  as  the  northeast  trade-winds  have,  we  might  ex- 
pect, according  to  this  hypothesis,  more  rains  in  the  northern — 
and,  consequently,  more  and  larger  rivers — than  in  the  southern 
hemisphere.  A  glance  at  Plate  YIII.  will  show  how  very  much 
larger  that  part  of  the  ocean  over  which  the  southeast  trades  pre- 
vail is  than  that  where  the  northeast  trade-winds  blow. 

186.  This  estimate  as  to  the  quantity  of  rain  in  the  two  hem- 
ispheres is  one  which  is  not  capable  of  verification  by  any  more 
than  the  rudest  approximations ;  for  the  greater  extent  of  south- 
east trades  on  one  side,  and  of  high  mountains  on  the  other,  must 
each  of  necessity,  and  independent  of  other  agents,  have  their  ef- 
fects. Nevertheless,  this  estimate  gives  as  close  an  approxima- 
tion as  we  can  make  out  from  our  data. 

187.  The  rainy  seasons,  Jioio  caused. — The  calm  and  trade- 
wind  regions  or  belts  move  up  and  down  the  earth,  annually,  in 
latitude  nearly  a  thousand  miles.  In  July  and  August  the  zone 
of  equatorial  calms  is  found  between  7°  north  and  12°  north; 
sometimes  higher ;  in  March  and  April,  between  latitude  5°  south 
and  2°  north. 

188.  "With  this  fact  and  these  points  of  view  before  us,  it  is 
easy  to  perceive  why  it  is  that  we  have  a  rainy  season  in  Oregon, 


92  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

a  rainy  and  dry  season  in  California,  another  at  Panama,  two  at 
Bogota,  none  in  Peru,  and  one  in  Chili. 

189.  In  Oregon  it  rains  every  month,  but  about  five  times  more 
in  the  winter  than  in  the  summer  months. 

The  winter  there  is  the  summer  of  the  southern  hemisphere, 
when  this  steam-engine  (§  168)  is  working  with  the  greatest  press- 
ure. The  vapor  that  is  taken  up  by  the  southeast  trades  is  borne 
alono'  over  the  region  of  northeast  trades  to  latitude  35°  or  40° 
north,  where  it  descends  and  appears  on  the  surface  with  the 
southwest  winds  of  those  latitudes.  Driving  upon  the  highlands 
of  the  continent,  this  vapor  is  condensed  and  precipitated,  during 
this  part  of  the  year,  almost  in  constant  showers,  and  to  the  depth 
of  about  thirty  inches  in  three  months. 

190.  In  the  winter,  the  calm  belt  of  Cancer  approaches  the 
equator.  This  whole  system  of  zones,  viz.,  of  trades,  calms,  and 
westerly  winds,  follows  the  sun ;  and  they  of  our  hemisphere  are 
nearer  the  equator  in  the  winter  and  spring  months  than  at  any 
other  season. 

191.  The  southwest  winds  commence  at  this  season  to  prevail 
as  far  down  as  the  lower  part  of  California.  In  winter  and  spring, 
the  land  in  California  is  cooler  than  the  sea  air,  and  is  quite  cold 
enough  to  extract  moisture  from  it.  But  in  summer  and  autumn 
the  land  is  the  warmer,  and  can  not  condense  the  vapors  of  water 
held  by  the  air.  So  the  same  cause  which  made  it  rain  in  Ore- 
gon now  makes  it  rain  in  California.  As  the  sun  returns  to  the 
north,  he  brings  the  calm  belt  of  Cancer  and  the  northeast  trades 
along  with  him  ;  and  now,  at  places  where,  six  months  before,  the 
southwest  winds  were  the  prevailing  winds,  the  northeast  trades 
are  found  to  blow.  This  is  the  case  in  the  latitude  of  California. 
The  prevailing  winds,  then,  instead  of  going  from  a  warmer  to  a 
cooler  climate,  as  before,  are  going  the  opposite  way.  Conse- 
quently, if,  under  these  circumstances,  they  have  the  moisture  in 
them  to  make  rains  of,  they  can  not  precipitate  it. 

192.  Proof,  if  proof  were  wanting  that  the  prevailing  winds  in 
the  latitude  of  California  are  from  the  westward,  is  obvious  to  all 
who  cross  the  Eocky  ]\Iountains  or  ascend  the  Sierra  ]\Iadre.  In 
the  pass  south  of  the  Great  Salt  Lake  basin  those  west  winds 


THE  ATMOSPHERE,  93 

have  worn  away  the  hills  and  polished  the  rock  by  their  ceaseless 
abrasion  and  the  scouring  effects  of  the  driving  sand.  Those  who 
have  crossed  this  pass  are  astonished  at  the  force  of  the  wind  and 
the  marks  there  exhibited  of  its  GEOLOGICAL  agencies. 

193.  Panama  is  in  the  region  of  equatorial  calms.  This  belt 
of  calms  travels  during  the  year,  back  and  forth,  over  about  17° 
of  latitude,  coming  farther  north  in  the  summer,  where  it  tarries 
for  several  months,  and  then  returning  so  as  to  reach  its  extreme 
southern  latitude  some  time  in  IMarch  or  April.  Where  these 
calms  are  it  is  always  raining,  and  the  chart*  shows  that  they  hang- 
over the  latitude  of  Panama  from  June  to  November ;  consequent- 
ly, from  June  to  I^ovember  is  the  rainy  season  at  Panama.  The 
rest  of  the  year  that  place  is  in  the  region  of  the  northeast  trades, 
which,  before  they  arrive  there,  have  to  cross  the  mountains  of  the 
isthmus,  on  the  cool  tops  of  which  they  deposit  their  moisture, 
and  leave  Panama  rainless  and  pleasant  until  the  sun  returns  north 
with  the  belt  of  equatorial  calms  after  him.  They  then  push  the 
belt  of  northeast  trades  farther  to  the  north,  occupy  a  part  of  the 
winter  zone,  and  refresh  that  part  of  the  earth  with  summer  rains. 
This  belt  of  calms  moves  over  more  than  double  of  its  breadth, 
and  nearly  the  entire  motion  from  south  to  north  is  accomplished 
generally  in  two  months,  May  and  June.  Take  the  parallel  of  4° 
north  as  an  illustration :  during  these  two  months  the  entire  belt 
of  calms  crosses  this  parallel,  and  then  leaves  it  in  the  region  of 
the  southeast  trades.  During  these  two  months  it  was  pouring 
down  rain  on  that  parallel.  After  the  calm  belt  passes  it  the  rains 
cease,  and  the  people  in  that  latitude  have  no  more  wet  weather 
till  the  fall,  when  the  belt  of  calms  recrosses  this  parallel  on  its 
way  to  the  south.  By  examining  the  "  Trade- wind  Chart,"  it 
may  be  seen  what  the  latitudes  are  that  have  two  rainy  seasons, 
and  that  Bogota  is  within  the  bi-rainy  latitudes. 

194.  The.  Rai7iless  Hegions, — The  coast  of  Peru  is  within  the 
region  of  perpetual  southeast  trade-winds.  Though  the  Peruvian 
shores  are  on  the  verge  of  the  great  South  Sea  boiler,  yet  it  never 
rains  there.     The  reason  is  plain. 

195.  The   southeast  trade-winds  in  the  Atlantic  Ocean  first 

*  Vide  Trade-ivind  Chart  (Maury's  Wind  and  Current). 


94  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

strike  the  water  on  tlie  coast  of  Africa.  Traveling  to  the  north- 
west, they  blow  obliquely  across  the  ocean  until  they  reach  the 
coast  of  Brazil.  By  this  time  they  are  heavily  laden  with  vapor, 
which  they  continue  to  bear  along  across  the  continent,  depositing 
it  as  they  go,  and  supplying  with  it  the  sources  of  the  E,io  de  la 
Plata  and  the  southern  tributaries  of  the  Amazon.  Finally  they 
reach  the  snow-capped  Andes,  and  here  is  wrung  from  them  the 
last  particle  of  moisture  that  that  very  low  temperature  can  extract. 
Reaching  the  summit  of  that  range,  they  now  tumble  down  as 
cool  and  dry  winds  on  the  Pacific  slopes  beyond.-  Meeting  with 
no  evaporating  surface,  and  with  no  temperature  colder  than  that 
to  which  they  were  subjected  on  the  mountain-tops,  they  reach 
the  ocean  before  they  again  become  charged  with  fresh  vapor,  and 
before,  therefore,  they  have  any  which  the  Peruvian  climate  can 
extract.  The  last  they  had  to  spare  was  deposited  as  snow  on 
the  tops  of  the  Cordilleras,  to  feed  mountain  streams  under  the 
heat  of  the  sun,  and  irrigate  the  valleys  on  the  western  slopes. 
Thus  we  see  how  the  top  of  the  Andes  becomes  the  reservoir  from 
which  are  supplied  the  rivers  of  Chili  and  Peru. 

196.  The  other  rainless  or  almost  rainless  regions  are  the  west- 
ern coasts  of  Mexico,  the  deserts  of  Africa,  Asia,  North  America, 
and  Australia.  Now  study  the  geographical  features  of  the  coun- 
try surrounding  those  regions  ;  see  how  the  mountain  ranges  run  ; 
then  turn  to  Plate  YIII.  to  see  how  the  winds  blow,  and  where 
the  sources  are  (§  112)  which  supply  them  with  vapors.  This 
plate  shows  the  prevailing  direction  of  the  v/ind  only  at  sea ;  but, 
knowing  it  there,  we  may  infer  what  it  is  on  the  land.  Suppos- 
ing it  to  prevail  on  the  land  as  it  generally  does  in  corresponding 
latitudes  at  sea,  then  the  Plate  will  suggest  readily  enough  how 
the  winds  that  blow  over  these  deserts  came  to  be  robbed  of  their 
moisture,  or,  rather,  to  have  so  much  of  it  taken  from  them  as  to 
reduce  their  dew-point  below  the  Desert  temperature ;  for  the  air 
can  never  deposit  its  moisture  token  its  temperature  is  higher  than 
its  dexo-jpoint. 

197.  We  have  a  rainless  region  about  the  Bed  Sea,  because  the 
Bed  Sea,  for  the  most  part,  lies  within  the  northeast  trade-wind 
region,  and  these  winds,  when  they  reach  that  region,  are  dry 


THE  ATMOSPHERE.  95 

winds,  for  tliey  have  as  yet,  in  their  course,  crossed  no  wide  sheets 
of  water  from  which  they  could  take  up  a  supply  of  vapor. 

198.  Most  of  New  Holland  lies  -within  the  southeast  trade-wind 
region  ;  so  does  most  of  inter-tropical  South  America.  But  inter- 
tropical South  America  is  the  land  of  showers.  The  largest  riv- 
ers and  most  copiously  watered  country  in  the  world  are  to  he 
found  there,  whereas  almost  exactly  the  reverse  is  the  case  in  Aus- 
tralia. Whence  this  difference  ?  Examine  the  direction  of  the 
winds  with  regard  to  the  shore-line  of  these  two  regions,  and  the 
explanation  will'  at  once  he  suggested.  In  Australia — east  coast 
— the  shore-line  is  stretched  out  in  the  direction  of  the  trades  ;  in 
South  America — east  coast — it  is  perpendicular  to  their  direction. 
In  Australia,  they  fringe  this  shore  only  with  their  vapor,  and  so 
stint  that  thirsty  land  with  showers  that  the  trees  can  not  afford  to 
spread  their  leaves  out  to  the  sun,  for  it  evaporates  all  the  moist- 
ure from  them ;  their  instincts,  therefore,  teach  them  to  turn  their 
edges  to  his  rays.  In  inter-tropical  South  America,  the  trade- 
winds  blow  perpendicularly  upon  the  shore,  penetrating  the  very 
heart  of  the  country  with  their  moisture.  Here  the  leaves,  meas- 
uring many  feet  square — as  the  plantain,  &c. — turn  their  broad 
sides  up  to  the  sun,  and  court  his  rays. 

199.  Why  there  is  'more  rain  on  07ie  side  of  a  mountain  than 
on' the  other.  ■ 

We  may  now,  from  what  has  been  said,  see  why  the  Andes  and 
all  other  mountains  which  lie  athwart  the  course  of  the  winds  have 
a  dry  and  a  rainy  side,  and  how  the  prevailing  winds  of  the  lati- 
tude determine  which  is  the  rainy  and  which  the  dry  side. 

Thus,  let  us  take  the  southern  coast  of  Chili  for  illustration. 
In  our  summer  time,  when  the  sun  comes  north,  and  drags  after 
him  his  belts  of  perpetual  winds  and  calms,  that  coast  is  left  with- 
in the  regions  of  the  northwest  winds — the  winds  that  are  coun- 
ter to  the  southeast  trades — which,  cooled  ^y  the  winter  temper- 
ature of  the  highlands  of  Chili,  deposit  their  moisture  copiously. 
During  the  rest  of  the  year,  the  most  of  Chili  is  in  the  region  of 
the  southeast  trades,  and  the  same  causes  which  operate  in  Cali- 
fornia to  prevent  rain  there,  operate  in  Chili ;  only  the  dry  season 
in  one  place  is  the  rainy  season  of  the  other. 


96        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

Hence  we  see  that  the  weather  side  of  all  such  mountains  as  the 
Ancles  is  the  wet  side,  and  the  lee  side  the  dry. 

200.  The  same  phenomenon,  from  a  like  cause,  is  repeated  in 
inter-tropical  India,  only  in  that  country  each  side  of  the  mountain 
is  made  alternately  the  wet  and  the'  dry  side  by  a  change  in  the 
prevailing  direction  of  the  wind.  Plate  VIII.  shows  India  to  be 
in  one  of  the  monsoon  regions :  it  is  the  most  famous  of  them  all. 
From  October  to  April  the  northeast  trades  prevail.  They  evap- 
orate from  the  Bay  of  Bengal  water  enough  to  feed  with  rains, 
during  this  season,  the  western  shores  of  this  bay  and  the  Ghauts 
range  of  mountains.  This  range  holds  the  relation  to  these  winds 
that  the  Andes  of  Peru  (§  194)  hold  to  the  southeast  trades ;  it 
first  cools  and  then  relieves  them  of  their  moisture,  and  they  tum- 
ble down  on  the  western  slopes  of  the  Ghauts,  Peruvian-like 
(§  199),  cool,  rainless,  and  dry ;  wherefore  that  narrow  strip  of 
country  between  the  Ghauts  and  the  Arabian  Sea  would,  like 
that  in  Peru  between  the  Andes  and  the  Pacific,  remain  without 
rain  forever,  were  it  not  for  other  agents  which  are  at  work  about 
India  and  not  about  Peru.  The  work  of  the  agents  to  which  I 
allude  is  felt  in  the  monsoons,  and  these  prevail  in  India  and  not 
in  Peru. 

201.  After  the  northeast  trades  have  blown  out  their  season, 
which  in  India  ends  in  April  (§  200),  the  great  arid  plains  of  Cen- 
tral Asia,  of  Tartary,  Thibet,  and  Mongolia,  become  heated  up ; 
they  rarefy  the  air  of  the  northeast  trades,  and  cause  it  to  ascend. 
This  rarefaction  and  ascent,  by  their  demand  for  an  indraught,  are 
felt  by  the  air  which  the  southeast  trade-winds  bring  to  the  equa- 
torial Doldrums  of  the  Indian  Ocean :  it  rushes  over  into  the 
northern  hemisphere  to  supply  the  upward  draught  from  the  heat- 
ed plains  as  the  southwest  monsoons.  The  forces  of  diurnal  ro- 
tation assist  (§  44)  to  give  these  winds  their  westing.  Thiis  the 
southeast  trades,  in  certain  parts  of  the  Indian  Ocean,  are  con- 
verted, during  the  summer  and  early  autumn,  into  southwest 
monsoons.  These  then  come  from  the  Indian  Ocean  and  Sea  of 
Arabia  loaded  with  moisture,  and,  striking  with  it  perpendicularly 
upon  the  Ghauts,  precipitate  upon  that  narrow  strip  of  land  be- 
tween this  range  and  the  Arabian  Sea  an  amount  of  water  that  is 


THE  ATMOSPHERE.  97 

truly  astonishing.  Here,  then,  are  not  only  the  conditions  for 
causing  more  rain,  now  on  the  west,  now  on  the  east  side  of  this 
mountain  range,  but  the  conditions  also  for  the  most  copious  pre- 
cipitation- Accordingly,  wlien  we  come  to  consult  rain  gauges, 
and  to  ask  meteorological  observers  in  India  about  the  fall  of  rain, 
they  tell  us  that  on  the  western  slopes  of  the  Ghauts  it  some- 
times reaches  the  enormous  depth  of  twelve  or  fifteen  inches  in 
one  day.'*  Were  the  Andes  stretched  along  the  eastern  instead 
of  the  western  coast  of  America,  we  should  have  an  amount  of 
precipitation  on  their  eastern  slopes  that  would  be  truly  astonish- 
ing; for  the  water  which  the  Amazon  and  the  other  majestic 
streams  of  South  America  return  to  the  ocean  would  still  be  pre- 
cipitated between  the  sea-shore  and  the  crest  of  these  mountains. 

202.  These  winds  of  India  then  continue  their  course  to  the 
Himalaya  range  as  dry  winds.  In  crossing  this  range,  they  are 
subjected  to  a  lower  temperature  than  that  to  which  they  were  ex- 
posed in  crossing  the  Ghauts.  Here  they  drop  more  of  their 
moisture  in  the  shape  of  snow  and  rain,  and  then  pass  over  into 
the  thirsty  lands  beyond  with  scarcely  enough  vapor  in  them  to 
make  even  a  cloud.  Thence  they  ascend  into  the  upper  air,  there 
to  become  counter-currents  in  the  general  system  of  atmospherical 
circulation.  By  studying  Plate  VIII.,  where  the  rainless  regions 
and  inland  basins,  as  well  as  the  course  of  the  prevailing  winds, 
are  shown,  these  facts  will  become  obvious. 

203.  The  Regions  of  Greatest  Precipitation, — We  shall  now 
be  enabled  to  determine,  if  the  views  which  I  have  been  endeav- 
oring to  present  be  correct,  what  parts  of  the  earth  are  subject  to 
the  greatest  fall  of  rain.  They  should  be  on  the  slopes  of  those 
mountains  which  the  trade-winds  first  strike,  after  having  blown 
across  the  greatest  tract  of  ocean.  The  more  abrupt  the  elevation, 
and  the  shorter  the  distance  between  the  mountain  top  and  the 
ocean  (§  199),  the  greater  the  amount  of  precipitation. 

If,  therefore,  we  commence  at  the  parallel  of  about  30°  north  in 
the  Pacific,  where  the  northeast  trade-winds  first  strike  that  ocean, 
and  trace  them  through  their  circuits  till  they  first  strike  high  land, 
we  ought  to  find  such  a  place  of  heavy  rains. 

*  Keith  Johnston. 


98  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

204.  Commencing  at  this  parallel  of  30°,  therefore,  in  the  North 
Pacific,  and  tracing  thence  the  course  of  the  northeast  trade-winds, 
we  shall  find  that  they  blow  thence,  and  reach  the  region  of  equa- 
torial calms  near  the  Caroline  Islands.  Here  they  rise  up  ;  but, 
instead  of  pursuing  the  same  course  in  the  upper  stratum  of  winds 
through  the  southern  hemisphere,  they,  in  consequence  of  the  ro- 
tation of  the  earth  (§  126),  are  made  to  take  a  southeast  course. 
They  keep  in  this  upper  stratum  until  they  reach  the  calms  of 
Capricorn,  between  the  parallels  of  30°  and  40°,  after  which  they 
become  the  prevailing  northwest  winds  of  the  southern  hemisphere, 
wliich  correspond  to  the  southwest  of  the  northern.  Continuing 
on  to  the  southeast,  they  are  now  the  surface  winds  ;  they  are  go- 
ing from  warmer  to  cooler  latitudes ;  they  become  as  the  wet 
sponge  (§  177),  and  are  abruptly  intercepted  by  the  Andes  of 
Patagonia,  whose  cold  summit  compresses  them,  and  with  its  lo\7 
dew-point  squeezes  the  water  out  of  them.  Captain  King  found 
the  astonishing  fall  of  water  here  of  nearly  thirteen  feet  (one  hund- 
red and  fifty-one  inches)  in  forty-one  days ;  and  Mr.  Darwin  reports 
that  the  sea  water  along  this  part  of  the  South  American  coast  is 
sometimes  quite  fresh,  from  the  vast  quantity  of  rain  that  falls. 

205.  We  ought  to  expect  a  corresponding  rainy  region  to  be 
found  to  the  north  of  Oregon  ;  but  there  the  mountains  are  not  so 
high,  the  obstruction  to  the  southwest  winds  is  not  so  abrupt,  the 
highlands  are  farther  from  the  coast,  and  the  air  which  these  winds 
carry  in  their  circulation  to  that  part  of  the  coast,  though  it  be  as 
heavily  charged  with  moisture  as  at  Patagonia,  has  a  greater  ex- 
tent of  country  over  which  to  deposit  its  rain,  and,  consequently, 
the  fall  to  the  square  inch  will  not  be  as  great.* 

206.  In  like  manner,  we  should  be  enabled  to  say  in  what  part 
of  the  world  the  most  equable  climates  are  to  be  found.  Tliey  are 
to  be  found  in  the  equatorial  calms,  where  the  northeast  and  south- 
east trades  meet  fresh  from  the  ocean,  and  keep  the  temperature 
uniform  under  a  canopy  of  perpetual  clouds. 

*  I  have,  through  the  kindness  of  A.  Holbrook,  Esq.,  United  States  Attorney  for 
Oregon,  received  the  Oregon  Spectator  of  February  13,  1851,  containing  the  Rev.  G. 
H.  Atkinson's  Meteorological  Journal,  kept  in  Oregon  City  during  the  month  of  Jan- 
uar}'^,  1851.  The  quantity  of  rain  and  snow  for-that  month  is  13.63  inches,  or  about 
one  third  the  average  quantity  that  falls  at  Washington  during  the  year. 


THE  ATMOSPHERE.  99 

207.  Amoimt  of  Eva])oration. — The  mean  annual  fall  of  rain 
on  the  enth'e  surface  of  the  earth  is  estimated  at  about  five  feet. 

208.  To  evaporate  water  enough  annually  from  the  ocean  to 
cover  the  earth,  on  the  average,  five  feet  deep  with  rain  ;  to  trans- 
port it  from  one  zone  to  another ;  and  to  precipitate  it  in  the  right 
places,  at  suitable  times,  and  in  the  proportions  due,  is  one  of  the 
offices  of  the  grand  atmospherical  machine.  This  water  is  evap- 
orated principally  from  the  torrid  zone.  Supposing  it  all  to  come 
thence,  we  shall  have,  encircling  the  earth,  a  belt  of  ocean  three 
thousand  miles  in  breadth,  from  which  this  atmosphere  evaporates 
a  layer  of  water  annually  sixteen  feet  in  depth.  And  to  hoist  up 
as  high  as  the  clouds,  and  lower  down  again  all  the  water  in  a  lake 
sixteen  feet  deep,  and  three  thousand  miles  broad,  and  twenty-four 
thousand  long,  is  the  yearly  business  of  this  invisible  machinery. 
What  a  powerful  engine  is  the  atmosphere !  and  how  nicely  ad- 
justed must  be  all  the  cogs,  and  wheels,  and  springs,  and  compen- 
sations of  this  exquisite  piece  of  machinery,  that  it  never  wears 
out  nor  breaks  down,  nor  falls  to  do  its  work  at  the  right  time  and 
in  the  right  way ! 

209.  In  his  annual  report  to  the  Society  ( Transactions  of  the 
Bombay  Geographical  Society  from  May,  1849,  to  August,  1850, 
vol.  ix.).  Dr.  Buist,  the  secretary,  states,  on  the  authority  of  Mr. 
Laidly,  the  evaporation  at  Calcutta  to  be  "  about  fifteen  feet  an- 
nually ;  that  between  the  Cape  and  Calcutta  it  averages,  in  Octo- 
ber and  November,  nearly  three  fourths  of  an  inch  daily ;  between 
10°  and  20^  in  the  Bay  of  Bengal,  it  was  found  to  exceed  an  inch 
daily.  Supposing  this  to  be  double  the  average  throughout  the 
year,  we  should,"  continues  the  doctor,  "have  eighteen  feet  of 
evaporation  annually." 

210.  If,  in  considering  the  direct  observations  upon  the  daily 
rate  of  evaporation  in  India,  it  be  remembered  that  the  seasons 
there  are  divided  into  wet  and  dry  ;  that  in  the  dry  season,  evap- 
oration in  the  Indian  Ocean,  because  of  its  high  temperatui'e,  and 
also  of  the  high  temperature  and  dry  state  of  the  wind,  probably 
goes  on  as  rapidly  as  it  does  any  where  else  in  the  world ;  if, 
moreover,  we  remember  that  the  regular  trade- wind  regions  pi:oper 
at  sea  are  regions  of  small  precipitation  (§  179) ;  that  evaporation 


100       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

is  going  on  from  them  all  the  year  round,  we  shall  have  reason  to 
consider  the  estimate  of  sixteen  feet  annually  for  the  trade- wind 
surface  of  the  ocean,  not  too  high. 

211.  We  see  the  light  beginning  to  break  upon  us,  for  we  now 
beo-in  to  perceive  why  it  is  that  the> proportions  between  the  land 
and  water  were  made  as  we  find  them  in  nature.  If  there  had 
been  more  water  and  less  land,  we  should  have  had  more  rain, 
and  vice  versa;  and  then  climates  would  have  been  different  from 
what  they  now  are,  and  the  inhabitants,  animal  or  vegetable,  would 
not  have  been  as  they  are.  And  as  they  are,  that  wise  Being 
who,  in  his  kind  providence,  so  watches  over  and  regards  the  things 
of  this  world  that  he  takes  notice  of  the  sparrow's  fall,  and  num- 
bers the  very  hairs  of  our  head,  doubtless  designed  them  to  be. 

212.  The  mind  is  delighted,  and  the  imagination  charmed,  by 
contemplating  the  physical  arrangements  of  the  earth  from  such 
points  of  view  as  this  is  which  we  now  have  before  us ;  from  it 
the  sea,  and  the  air,  and  the  land,  appear  each  as  a  part  of  that 
grand  machinery  upon  which  the  well-being  of  all  the  inhabitants 
of  earth,  sea,  and  air  depends  ;  and  which,  in  the  beautiful  adap- 
tations that  we  are  pointing  out,  affords  new  and  striking  evidence 
that  they  all  have  their  origin  in  ONE  omniscient  idea,  just  as  the 
different  parts  of  a  watch  may  be  considered  to  have  been  con- 
structed and  arranged  according  to  07ie  human  design. 

213.  In  some  parts  of  the  earth,  the  precipitation  is  greater  than 
the  evaporation ;  thus  the  amount  of  water  borne  down  by  every 
river  that  runs  into  the  sea  may  be  considered  as  the  excess  of 
the  precipitation  over  the  evaporation  that  takes  place  in  the  val- 
ley drained  by  that  river. 

214.  This  excess  comes  from  the  sea ;  the  winds  convey  it  to 
the  interior  ;  and  the  forces  of  gravity,  dashing  it  along  in  mount- 
ain torrents  or  gentle  streams,  hurry  it  back  to  the  sea  again. 

215.  In  other  parts  of  the  earth,  the  evaporation  and  precipita- 
tion are  exactly  equal,  as  in  those  inland  basins  such  as  that  in 
which  the  city  of  Mexico,  Lake  Titicaca,  the  Caspian  Sea,  etc., 
etc.,  are  situated,  which  basins  have  no  ocean  drainage. 

216.  If  more  rain  fell  in  the  valley  of  the  Caspian  Sea  than  is 
evaporated  from  it,  that  sea  would  finally  get  full  and  overflow 
the  whole  of  that  great  basin.     If  less  fell  than  is  evaporated  from 


THE  ATMOSPHERE.  iQi 

it  again,  then  that  sea,  in  the  course  of  time,  would  dry  up,  and 
plants  and  animals  there  would  all  perish  for  the  want  of  water. 

217.  In  the  sheets  of  water  which  we  find  distributed  over 
that  and  every  other  inhabitable  inland  basin,  we  see  reservoirs 
or  evaporating  surfaces  just  sufficient  for  the  supply  of  that  de- 
gree of  moisture  which  is  best  adapted  to  the  well-being  of  the 
plants  and  animals  that  people  such  basins. 

218.  In  other  parts  of  the  earth  stiU,  we  find  places,  as  the  Des- 
ert of  Sahara,  in  which  neither  evaporation  nor  precipitation  takes 
place,  and  in  which  we  find  neither  plant  nor  animal. 

219.  Adaptations. — In  contemplating  the  system  of  terres- 
trial adaptations,  these  researches  teach  one  to  regard  the  mount- 
ain ranges  and  the  great  deserts  of  the  earth  as  the  astronomer 
does  the  counterpoises  to  his  telescope — though  they  be  mere  dead 
weights,  they  are,  nevertheless,  necessary  to  make  the  balance 
complete,  the  adjustments  of  his  machine  perfect.  These  coun- 
terpoises give  ease  to  the  motions,  stability  to  the  performance, 
and  accuracy  to  the  workings  of  the  instrument.  They  are  ^'€0?n- 
pensations.''' 

220.  Whenever  I  turn  to  contemplate  the  works  of  nature,  I 
am  struck  with  the  admirable  system  of  compensation,  with  the 
beauty  and  nicety  with  which  every  department  is  poised  by  the 
others  ;  things  and  principles  are  meted  out  in  directions  appar- 
ently the  most  opposite,  but  in  proportions  so  exactly  balanced  and 
nicely  adjusted  that  results  the  most  harmonious  are  produced. 

221.  It  is  by  the  action  of  opposite  and  compensating  forces 
that  the  earth  is  kept  in  its  orbit,  and  the  stars  are  held  suspend- 
ed in  the  azure  vault  of  heaven ;  and  these  forces  are  so  exquis- 
itely adjusted,  that,  at  the  end  of  a  thousand  years,  the  earth,  the 
sun,  and  moon,  and  every  star  in  the  firmament,  is  found  to  come 
and  stand  in  its  proper  place  at  the  proper  moment. 

222.  Nay,  philosophy  teaches  us  that  when  the  little  snow- 
drop, which  in  our  garden-walks  we  see  raising  its  beautiful  head, 
at  "the  singing  of  birds,"  to  remind  us  that  "the  winter  is  passed 
and  gone,"  was  created,  the  whole  mass  of  the  earth,  from  pole  to 
pole,  and  from  circumference  to  centre,  must  have  been  taken  into 
account  and  weighed,  in  order  that  the  proper  degree  of  strength 
might  be  given  to  its  tiny  fibres. 


102  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

223.  Botanists  tell  us  that  the  constitution  of  this  plant  is  such 
as  to  require  that,  at  a  certain  stage  of  its  growth,  the  stalk  should 
bend,  and  the  flower  should  bow  its  head,  that  an  operation  may 
take  place  which  is  necessary  in  order  that  the  herb  should  pro- 
duce seed  after  its  kind  ;  and  that,  after  this  fecundation,  its  veg- 
etable health  requires  that  it  should  lift  its  head  again  and  stand 
erect.  J^ow,  if  the  mass  of  the  earth  had  been  greater  or  less, 
the  force  of  gravity  would  have  been  different ;  in  that  case,  the 
strength  of  fibre  in  the  snow-drop,  as  it  is,  would  have  been  too 
much  or  too  little ;  the  plant  could  not  bow  or  raise  its  head  at 
the  right  time,  fecundation  could  not  take  place,  and  its  family 
would  have  become  extinct  with  the  first  individual  that  was 
planted,  because  its  "  seed"  would  not  have  been  "in  itself,"  and 
therefore  it  could  not  have  reproduced  itself,  and  its  creation  would 
have  been  a  failure. 

224.  Now,  if  we  see  such  perfect  adaptation,  such  exquisite 
adjustment,  in  the  case  of  one  of  the  smallest  flowers  of  the  field, 
how  much  more  may  we  not  expect  "compensation"  in  the  at- 
mosphere and  the  ocean,  upon  the  right  adjustment  and  due  per- 
formance of  which  depends  not  only  the  life  of  that  plant,  but  the 
well-being  of  every  individual  that  is  found  in  the  entire  vegeta- 
ble and  animal  kingdoms  of  the  world  ? 

225.  When  the  east  winds  blow  along  the  Atlantic  coast  for  a 
little  while,  they  bring  us  air  saturated  with  moisture  from  the 
Gulf  Stream,  and  we  complain  of  the  sultry,  oppressive,  heavy  at- 
mosphere ;  the  invalid  grows  worse,  and  the  well  man  feels  ill, 
because,  when  he  takes  this  atmosphere  into  his  lungs,  it  is  al- 
ready so  charged  with  moisture  that  it  can  not  take  up  and  carry 
off  that  which  encumbers  his  lungs,  and  which  nature  has  caused 
his  blood  to  bring  and  leave  there,  that  respiration  may  take  up 
and  carry  off.  At  other  times  the  air  is  dry  and  hot ;  he  feels 
that  it  is  conveying  off  matter  from  the  lungs  too  fast ;  he  real- 
izes the  idea  that  it  is  consuming  him,  and  he  calls  the  sensation 
burning. 

226.  Therefore,  in  considering  the  general  laws  which  govern 
the  physical  agents  of  the  universe,  and  regulate  them  in  the  due 
performance  of  their  offices,  I  have  felt  myself  constrained  to  set 
out  with  the  assumption  that,  if  Ahe  atmosphere  had  had  a  greater 


THE  ATMOSPHERE.  103 

or  less  capacity  for  moisture,  or  if  the  proportion  of  land  and  wa- 
ter had  been  different — if  the  earth,  air,  and  water  had  not  been 
in  exact  counterpoise — the  whole  arrangement  of  the  animal  and 
vegetable  kingdoms  would  have  varied  from  their  present  state. 
But  God,  for  reasons  which  man  may  never  know,  chose  to  make 
those  kingdoms  what  they  are ;  for  this  purpose  it  was  necessary, 
in  his  judgment,  to  establish  the  proportions  between  the  land 
and  water,  and  the  desert,  just  as  they  are,  and  to  make  the  ca- 
pacity of  the  air  to  circulate  heat  and  moisture  just  what  it  is, 
and  to  have  it  to  do  all  its  work  in  obedience  to  law  and  in  sub- 
servience to  order.  If  it  were  not  so,  why  was  power  given  to  the 
winds  to  lift  up  and  transport  moisture,  and  to  feed  the  plants  with 
nourishment  ?  or  why  was  the  property  given  to  the  sea  by  which 
its  waters  may  become  first  vapor,  and  then  fruitful  showers  or 
gentle  dews  ?  If  the  proportions  and  properties  of  land,  sea,  and 
air  were  not  adjusted  according  to  the  reciprocal  capacities  of  all 
to  perform  the  functions  required  by  each,  why  should  we  be  told 
that  He  "  measured  the  waters  in  the  hollow  of  his  hand,  and  com- 
prehended the  dust  in  a  measui'e,  and  weighed  the  mountains  in 
scales,  and  the  hills  in  a  balance  ?"  Why  did  he  span  the  heav- 
ens, but  that  he  might  mete  out  the  atmosphere  in  exact  propor- 
tion to  all  the  rest,  and  impart  to  it  those  properties  and  powers 
which  it  was  necessary  for  it  to  have,  in  order  that  it  might  per- 
form all  those  offices  and  duties  for  which  he  designed  it  ? 

227.  Harmonious  in  their  action,  the  air  and  sea  are  obedient 
to  law  and  subject  to  order  in  all  their  movements ;  when  we 
consult  them  in  the  performance  of  their  manifold  and  marvelous 
offices,  they  teach  us  lessons  concerning  the  wonders  of  the  deep, 
the  mysteries  of  the  sky,  the  greatness,  and  the  wisdom,  and  good- 
ness of  the  Creator,  which  make  us  wiser  and  better  men.  The 
investigations  into  the  broad-spreading  circle  of  phenomena  con- 
nected with  the  winds  of  heaven  and  the  waves  of  the  sea  are 
second  to  none  for  the  good  which  they  do  and  the  lessons  which 
they  teach.  The  astronomer  is  said  to  see  the  hand  of  God  in 
the  sky ;  but  does  not  the  right-minded  mariner,  who  looks  aloft 
as  he  ponders  over  these  things,  hear  his  voice  in  every  wave  of 
the  sea  that  "claps  its  hands,"  and  feel  his  presence  in  every 
breeze  that  blows  ? 


104  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  IV. 

LAND   AND    SEA   BEEEZES. 

Lieutenant  Jansen,  ^  228. — His  Contributions,  229. — The  Sea-breeze,  230. — An  Il- 
lustration, 231. — The  Land-breeze,  232. — Jansen's  Account  of  the  Land  and  Sea 
Breeze  in  the  East  Indies,  234.— A  Morning  Scene,  235.— The  Calm,  237.— The 
Inhabitants  of  the  Sea  going  to  Work,  239. — Noon,  240. — The  Sea-breeze  dies,  245. 
— The  Land-breeze,  247. — A  Discussion,  248. — Why  Land  and  Sea  Breezes  are 
not  of  equal  Freshness  on  the  Sea-shore  of  all  Countries,  252. — The  Sea-breeze  at 
Valparaiso,  255.— The  Night,  258.— A  Contrast,  263. 

228.  I  HAYE  "been  assisted  in  my  investigations  into  these  phe- 
nomena of  the  sea  by  many  thinking  minds  ;  among  those  whose 
debtor  I  am,  stands  first  and  foremost  the  clear  head  and  warm 
heart  of  a  foreign  officer,  Lieutenant  Marin  Jansen,  of  the  Dutch 
Navy,  whom  I  am  proud  to  call  my  friend.  He  is  an  ornament 
to  his  profession;  and  a  more  accomplished  officer  it  has  never 
been  my  good  fortune  to  meet  in  any  service.  He  has  entered 
this  magnificent  field  of  research  con  amore,  and  has  proved  to 
be  a  most  zealous  and  efficient  fellow-laborer.  Promotion  in  the 
Dutch  J^avy  unfortunately  goes  by  seniority  ;  if  it  went  by  merit, 
I  should,  I  am  sure,  have  the  pleasure  of  writing  of  him  as  admiral. 

229.  Jansen  has  served  many  years  in  the  East  Indies.  He 
observed  minutely  and  well.  He  has  enriched  my  humble  con- 
tributions to  the  "Physical  Geography  of  the  Sea"  with  contri- 
butions from  the  store-house  of  his  knowledge,  set  ofi"  and  present- 
ed in  many  fine  pictures,  and  has  appended  them  to  a  translation 
of  the  first  edition  of  this  work  into  the  Dutch  language.  He  has 
added  a  chapter  on  the  land  and  sea  breezes ;  another  on  the  chang- 
ing of  the  monsoons  in  the  East  Indian  Archipelago  :  he  has  also 
extended  his  remarks  to  the  northwest  monsoon,  to  hurricanes, 
the  southeast  trades  of  the  South  Atlantic,  and  to  winds  and  cur- 
rents generally. 

230.  In  many  parts  of  the  world  the  oppressive  heat  of  sum- 
mer is  modified,  and  the  climate  of  the  sea-shore  is  made  refresh- 


LAND  AND  SEA  BREEZES.  105 

ing  and  healtliM  by  the  alternation  of  winds  which  come  from  the 
sea  by  day,  and  from  the  land  by  night.  About  ten  in  the  morn- 
ing the  heat  of  the  sun  has  played  upon  the  land  with  sufScient 
intensity  to  raise  its  temperature  above  that  of  the  water.  A  por- 
tion of  this  heat,  being  imparted  to  the  superincumbent  air,  causes 
it  to  rise,  when  the  air,  first  from  the  beach,  then  from  the  sea,  to 
the  distance  of  several  miles,  begins  to  flow  in  with  a  most  de- 
lightful and  invigorating  freshness. 

231.  When  a  fire  is  kindled  on  the  hearth,  we  may,  if  we  will 
observe  the  moats  floating  in  the  room,  see  that  those  nearest  to 
the  chimney  are  the  first  to  feel  the  draught  and  to  obey  it — they 
are  drawn  into  the  blaze.  The  circle  of  inflowing  air  is  gradually 
enlarged,  until  it  is  scarcely  perceived  in  the  remote  parts  of  the 
room.  Now  the  land  is  the  hearth,  the  rays  of  the  sun  the  fire, 
and  the  sea,  with  its  cool  and  calm  air,  the  room  ;  and  thus  we 
have  at  our  firesides  the  sea-breeze  in  miniature. 

232.  When  the  sun  goes  down  the  fire  ceases ;  then  the  dry 
land  commences  to  give  off  its  surplus  heat  by  radiation,  so  that 
by  nine  or  ten  o'clock  it  and  the  air  above  it  are  cooled  below  the 
sea  temperature.  The  atmosphere  on  the  land  thus  becomes  heav- 
ier than  that  on  the  sea,  and,  consequently,  there  is  a  wind  sea- 
ward which  we  call  the  land-breeze. 

233.  Jansen  thus  describes  this  phenomenon  in  the  East  In- 
dies, where  one  must  live  fully  to  appreciate  its  benign  influences. 

234.  Jaxsen's  Account.* — "A  long  residence  in  the  East  In- 
dian Archipelago,  and,  consequently,  in  that  part  of  the  world  where 
the  investigations  of  the  Observatory  at  Washington  have  not  ex- 
tended, has  given  me  the  opportunity  of  studying  the  phenomena 
which  there  occur  in  the  atmosphere,  and  to  these  phenomena  my 
attention  was,  in  the  first  place,  directed.  I  was  involuntarily  led 
from  one  research  to  another,  and  it  is  the  result  of  these  investi- 
gations to  wliich  I  would  modestly  give  a  place  at  the  conclusion 
of  Maury's  Physical  Geography  of  the  Sea,  with  the  hope  that 
these  first-fruits  of  the  log-books  of  the  ^Netherlands  may  be 
speedily  followed  by  more  and  better. 

*^  Jansen's  Appendix  to  the  Physical  Geography  of  the  Sea,  translated  from  the 
Dutch  by  Mrs.  Dr.  Breed,  Washington. 


106       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

235.  "Upon  the  northern  coast  of  Java,  the  phenomenon  of  daily 
land  and  sea  breezes  is  finely  developed.  There,  as  the  gorgeous 
"  eye  of  day"  rises  almost  perpendicularly  from  the  sea  with  fiery 
ardor,  in  a  cloudless  sky,  it  is  greeted  by  the  volcanoes  with  a  col- 
umn of  white  smoke,  which,  ascending  from  the  conical  summits 
high  in  the  firmament  above,  forms  a  crown,  or  assumes  the  shape 
of  an  immense  bouquet,*  that  they  seem  to  ofier  to  the  dawn ; 
then  the  joyful  land-breeze  plays  over  the  flood,  which,  in  the  tor- 
rid zone,  furnishes,  with  its  fresh  breath,  so  much  enjoyment  to 
the  inhabitants  of  that  sultry  belt  of  earth,  for,  by  means  of  it, 
every  thing  is  refreshed  and  beautified.  Then,  under  the  influ- 
ence of  the  glorious  accompaniments  of  the  break  of  day,  the  si- 
lence of  the  night  is  awakened,  and  we  hear  commencing  every 
where  the  morning  hymn  of  mute  nature,  whose  gesticulation  is 
so  expressive  and  sublime.  All  that  lives  feels  the  necessity  of 
pouring  forth,  each  in  its  way,  and  in  various  tones  and  accents, 
from  the  depths  of  inspiration,  a  song  of  praise. 

236.  "The  air,  still  filled  with  the  freshness  of  the  evening  dew, 
bears  aloft  the  enraptured  song,  as,  mingled  with  the  jubilee  tones 
which  the  contemplation  of  nature  every  where  forces  from  the 
soul,  it  gushes  forth  in  deep  earnestness  to  convey  the  daily 
thank-oflering  over  the  sea,  over  hill  and  dale.j 

237.  "As  the  sun  ascends  the  sky,  the  azure  vault  is  bathed 
in  dazzling  light ;  now  the  land-breeze,  wearied  with  play,  goes  to 
rest.  Here  and  there  it  still  plays  over  the  water,  as  if  it  could 
not  sleep ;  but  finally  becoming  exhausted,  it  sinks  to  repose  in 
the  stillness  of  the  calm.  But  not  so  with  the  atmosphere:  it 
sparkles,  and  glitters,  and  twinkles,  becoming  clear  under  the  in- 
creasing heat,  while  the  gentle  swelling  of  the  now  polished  waves, 
reflects,  like  a  thousand  mirrors,  the  rays  of  light  which  dance  and 
leap  to  the  tremulous  but  vertical  movements  of  the  atmosphere. 

238.  "Like  pleasant  visions  of  the  night,  that  pass  before  the 

*  Upon  the  coast  of  Java  I  saw  daily,  during  the  east  monsoon,  such  a  column  of 
smoke  ascending  at  sunrise  from  Bromo,  Lamongan,  and  Smiro.  Probably  there  is 
then  no  wind  above. — Jansen. 

t  In  the  very  fine  mist  of  the  morning,  a  noise — for  example,  the  firing  of  cannon 
— at  a  short  distance  is  scarcely  heard,  while  at  midday,  with  the  sea-breeze,  it  pen- 
etrates for  miles  with  great  distinctness. — Jansen. 


LAND  AND  SEA  BREEZES.  107 

mind  in  sleep,  so  do  sweet  phantoms  hover  about  the  land-breeze 
as  it  slumbers  upon  the  sea.  The  shore  seems  to  approach  and  to 
display  all  its  charms  to  the  mariner  in  the  offing.  All  objects 
become  distinct  and  more  clearly  delineated,*  while,  upon  the  sea, 
small  fishing-boats  loom  up  like  large  vessels.  The  seaman,  drift- 
ing along  the  coast,  and  misled  by  the  increasing  clearness  and 
mirage,  believes  that  he  has  been  driven  by  a  current  toward  the 
land ;  he  casts  the  lead,  and  looks  anxiously  out  for  the  sea- 
breeze,  in  order  to  escape  from  what  he  believes  to  be  threatening 
danger.!  The  planks  burn  under  his  feet ;  in  vain  he  spreads  the 
awning  to  shelter  himself  from  the  broiling  sun.  Its  rays  are  op- 
pressive ;  repose  does  not  refresh ;  motion  is  not  agreeable. 

239.  "The  inhabitants  of  the  deep,  awakened  by  the  clear  light 
of  day,  prepare  themselves  for  labor.  Corals,  and  thousands  of 
Crustacea,  await,  perhaps  impatiently,  the  coming  of  the  sea-breeze, 
which  shall  cause  evaporation  to  take  place  more  rapidly,  and  thus 
provide  them  with  a  bountiful  store  of  building  material  for  their 
picturesque  and  artfully  constructed  dwellings :  these  they  know 
how  to  paint  and  to  polish  in  the  depths  of  the  sea  more  beauti- 
fully than  can  be  accomplished  by  any  human  art.  Like  them, 
also,  the  plants  of  the  sea  are  dependent  upon  the  winds,  upon  the. 
clouds,  and  upon  the  sunshine ;  for  upon  these  depend  the  vapor 
and  the  rains  which  feed  the  streams  that  bring  nourishment  for 
them  into  the  sea.  J 

240.  "When  the  sun  reaches  the  zenith,  and  his  stern  eye,  with 
burning  glare,  is  turned  more  and  more  upon  the  Java  Sea,  the  air 
seems  to  fall  into  a  magnetic  sleep ;  yet,  even  as  the  magnetizer 
exercises  his  will  upon  his  subject,  and  the  latter,  with  uncertain 
and  changeable  gestures,  gradually  puts  himself  in  motion,  and 
sleeping  obeys  that  will,  so  also  we  see  the  slow  efforts  of  the  sea- 

*  The  transparency  of  the  atmosphere  is  so  great  that  we  can  sometimes  discover 
Venus  in  the  sky  in  the  middle  of  the  day. — Jansen. 

t  Especially  in  the  rainy  season  the  land  looms  very  greatly ;  then  we  see  mount- 
ains which  are  from  5000  to  6000  feet  high  at  a  distance  of  80  or  100  English  miles. 

t  The  archipelago  of  coral  islands  on  the  north  side  of  the  Straits  of  Sunda  is 
remarkable.  Before  the  salt  water  flowed  from  the  Straits  it  was  deprived  of  the  solid 
matter  of  which  the  Thousand  Islands  are  constructed.  A  similar  group  of  islands  is 
found  between  the  Straits  of  Macassar  and  Balie. — Jansen. 


108       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

breeze  to  repress  the  vertical  movements  of  the  ah',  and  to  obey 
the  will  which  calls  it  to  the  land.  This  vertical  movement  ap- 
pears to  be  not  easily  overcome  by  the  horizontal  which  we  call 
wind.  Yonder,  far  out  upon  the  sea,  arises  and  disappears  alter- 
nately a  darker  tint  upon  the  otherwise  shining  sea-carpet ;  final- 
ly, that  tint  remains  and  approaches ;  that  is  the  long-wished-for 
sea-breeze :  and  yet  it  is  sometimes  one,  yes,  even  two  hours  be- 
fore that  darker  tint  is  permanent,  before  the  sea-breeze  has  regu- 
larly set  in. 

241.  "  Now  small  white  clouds  begin  to  rise  above  the  hori- 
zon ;  to  the  experienced  seaman  they  are  a  prelude  to  a  fresh  sea- 
breeze.  We  welcome  the  first  breath  from  the  sea ;  it  is  cooling, 
but  it  soon  ceases ;  presently  it  is  succeeded  by  other  grateful 
puffs  of  air,  which  continue  longer ;  presently  they  settle  down 
into  the  regular  sea-breeze,  with  its  cooling  and  refreshing  breath. 

242.  "  The  sun  declines,  and  the  sea- wind — that  is,  the  com- 
mon trade-wind  or  monsoon  which  is  drawn  toward  the  land — is 
awakened.  It  blows  right  earnestly,  as  if  it  would  perform  its 
daily  task  with  the  greatest  possible  ado. 

243.  "  The  air,  itself  refreshed  upon  the  deep,  becomes  gray 
from  the  vapor  which  envelops  the  promontories  in  mist,  and  cur- 
tains the  inland  with  dark  clouds.  The  land  is  discernible  only 
by  the  darker  tint  which  it  gives  to  the  mist ;  but  the  distance 
can  not  be  estimated.  The  sailor  thinks  himself  farther  from 
shore  than  he  really  is,  and  steers  on  his  course  carelessly,  while 
the  capricious  wind  lashes  the  waters,  and  makes  a  short  and 
broken  sea,  from  the  white  caps  of  which  light  curls  are  torn,  with 
sportive  hand,  to  float  away  like  party-colored  stream^ers  in  the 
sunbeam.  In  the  mean  Avhile  clouds  appear  now  and  then  high  in 
au',  yet  it  is  too  misty  to  see  far. 

244.  "  The  sun  approaches  the  horizon.  Far  over  the  land  the 
clouds  continue  to  heap  up ;  already  the  thunder  is  heard  among 
the  distant  hills  ;  the  thunder-bolts  reverberate  from  hill-side  to 
hill-side,  while  through  the  mist  the  sheets  of  lightning  are  seen.* 

*  At  Buitenzorg,  near  Batavia,  40  English  miles  from  the  shore,  five  hundred  feet 
above  the  sea,  with  high  hills  around,  these  thunder-storms  occur  between  4  P.M.  and 
8  P.M. 


LAND  AND  SEA  BREEZES.  109 

245.  "Finally,  the  "  king  of  day"  sinks  to  rest ;  now  the  mist 
gradually  disappears,  and  as  soon  as  the  Avind  has  laid  down  the 
lash,  the  sea,  which,  chafing  and  fretting,  had  with  curled  mane 
resisted  its  violence,  begins  to  go  down  also.  Presently  both 
winds  and  waves  are  hushed,  and  all  is  again  still.  Above  the 
sea,  the  air  is  clearer  or  slightly  clouded ;  above  the  land,  it  is 
thick,  dark,  and  swollen.  To  the  feelings,  this  stillness  is  pleas- 
ant. The  sea-breeze,  the  driving  brine  that  has  made  a  salt-pan 
of  the  face,  the  short,  restless  sea,  the  dampness — all  have„grown 
wearisome,  and  welcome  is  the  calm.  There  is,  however,  a  some- 
what of  dimness  in  the  air,  an  uncertain  but  threatening  appear- 
ance. Presently,  from  the  dark  mass  of  clouds,  which  hastens  the 
change  of  day  into  night,  the  thunder-storm  peals  forth.  The  rain 
falls  in  torrents  in  the  mountains,  and  the  clouds  gradually  over- 
spread the  whole  sky.  But  for  the  wind,  wdiich  again  springs 
up,  it  would  be  alarming  to  the  sailor,  who  is  helpless  in  a  calm. 
What  change  will  take  place  in  the  air  ?  The  experienced  sea- 
man, who  has  to  work  against  the  trade-wind  or  against  the  mon- 
soon, is  off  the  coast,  in  order  to  take  advantage  of  the  land-breeze 
(the  destroyer  of  the  trade)  so  soon  as  it  shall  come.  He  rejoices 
when  the  air  is  released  from  the  land  and  the  breeze  comes,  at 
first  feebly,  but  afterward  growing  stronger,  as  usual,  during  the 
whole  night.  If  the  land-breeze  meets  with  a  squall,  then  it  is 
brief,  and  becomes  feeble  and  uncertain.  We  sometimes  find  then 
the  permanent  sea-breeze  close  to  the  coast,  which  otherwise  re- 
mains twenty  or  more  English  miles  from  it. 

246.  "  One  is  not  always  certain  to  get  the  land-breeze  at  the 
fixed  time.  It  sometimes  sufters  itself  to  be  waited  for ;  some- 
times it  tarries  the  whole  night  long. 

247.  "During  the  greatest  part  of  the  rainy  season,  the  land- 
breeze  in  the  Java  Sea  can  not  be  depended  upon.  This  is  read- 
ily explained  according  to  the  theory  which  ascribes  the  origin  of 
the  sea  and  land  breezes  to  the  heating  of  the  soil  by  day, -and  the 
cooling  by  means  of  radiation  by  night ;  for,  during  the  rainy  sea- 
son, the  clouds  extend  over  land  and  sea,  interrupting  the  sun's 
rays  by  day,  and  the  radiation  of  heat  by  night,  thus  preventing 
the  variations  of  temperature;  and  fi'om  these  variations,  according 


110  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

to  this  theory,  the  land  and  sea  breezes  arise.  Yet  there  are  other 
tropical  regions  where  the  land  and  sea  breezes,  even  in  the  rainj 
season,  regularly  succeed  each  other. 

248.  "  The  warming  and  the  radiation  alone  are  therefore  not 
sufficient  to  explain  all  the  phenomena  of  land  and  sea  breezes, 
and  other  causes — electricity,  rain,  etc.,  appear  to  have  an  influ- 
ence upon  the  regularity  of  the  land  winds.* 

249.  "Upon  the  coast  of  Africa,  the  land-breeze  is  universally 
scorching  hot,  but  the  sea-breeze  is  cool  and  refreshing.  When 
this  is  the  case,  the  land-breeze  certainly  can  not  be  occasioned 
by  the  cooling  of  the  earth  by  radiation.  When  we  shall  have 
brought  together  all  the  observations  upon  the  various  phenomena 
which  the  land  and  sea  breezes  afford,  then  we  shall  be  able  to 
begin  to  found  upon  facts  a  theory  which  shall  explain  the  varied 
phenomena.  Thus,  among  other  things,  upon  the  west  coast  of 
Africa,  from  0°  27'  S.  to  15°  24'  S.,  according  to  Thomas  Miller,t 
from  June  to  October,  and,  above  all,  in  July,  there  are  heavy 
dews,  and  when  the  dews  are  very  heavy,  then  the  land  and  sea 
breezes  are  invariably  feeble — sometimes  very  faint." 

250.  [Lieutenant  Jansen's  remarks  are  both  instructive  and  sug- 
gestive. It  is  true  that  a  given  difference  of  temperature  between 
land  and  water,  though  it  may  be  sufficient  to  produce  the  phenom- 
ena of  land  and  sea  breezes  at  one  place,  will  not  be  adequate  to  the 
same  effect  at  another ;  and  the  reason  is  perfectly  philosophical. 

251.  It  is  easier  to  obstruct  and  turn  back  the  current  in  a 
sluggish  than  in  a  rapid  stream.  So,  also,  in  turning  a  current  of 
air  first  upon  the  land,  then  upon  the  sea — very  slight  alterations 
of  temperature  would  suffice  for  this  on  the  west  coast  of  Africa, 

*  My  observations  lead  me  to  suspect  that  the  position  of  the  moon  is  also  herein 
concerned.  In  the  eastern  outlet  of  Sourabaya,  during  the  east  monsoon,  there  is  at 
full  moon  little  land-breeze,  and  at  new  moon  little  sea-breeze.  I  afterward  made  the 
same  observation  in  the  Gulf  of  Darien.  Feb.  4,  1852.— At  the  Road  of  Carthagena 
(New  Granada),  full  moon,  sea-breeze  north,  under  reefed  top-sail,  fresh  gale ;  at  11 
P.M.,  feeble  and  easterly.  Feb.  5.— 11  A.M.,  sea-breeze  grows  faint.  1  P.M., 
stronger,  and  between  5  and  6  P.  M.  fresh  gale ;  double-reefed  top-sail.  Each  day 
somewhat  later  and  less  hard.  Thermometer  varying  between  79°  and  80°.  Barom- 
eter varying  between  763°  and  759°.  Upon  leaving  Chagres,  with  new  moon,  it  was 
by  day  mostly  feeble. — Jansen. 

t  Nautical  Magazine  for  June,  1855. — Jansen. 


LAND  AND  SEA  BREEZES. 


Ill 


in  and  about  the  equatorial  calms,  for  instance ;  there  the  air  is 
in  a  state  of  rest,  and  will  obey  the  slightest  call  in  any  direction 
— not  so  in  regions  where  the  trades  blow  over  the  land,  and  are 
strong.  It  requires,  under  such  circumstances,  a  considerable  de- 
gree of  rarefaction  to  check  them  and  produce  a  calm,  and  a  still 
farther  rarefaction  to  turn  them  back,  and  convert  them  into  a 
regular  sea-breeze. 

252.  Hence  the  scorching  land-breeze  on  the  west  coast  of  Af- 
rica: the  heat  there  may  not  have  been  intense  enough  to  pro- 
duce the  degree  of  rarefaction  required  to  check  and  turn  back  the 
southeast  trades.  In  that  part  of  the  world,  their  natural  course  is 
from  the  land  to  the  sea,  and  therefore,  if  this  view  be  correct,  the 
sea-breeze  should  be  more  feeble  than  the  land-breeze,  neither 
should  it  last  so  long. 

253.  But  on  the  opposite  side — on  the  coast  of  Brazil,  as  at 
Pernambuco,  for  instance — where  the  trade-wind  comes  from  the 
sea,  we  should  have  this  condition  of  things  reversed,  and  the  sea- 
breeze  will  prevail  for  most  of  the  time — then  it  is  the  land-breeze 
which  is  feeble  and  of  short  duration :  it  is  rarely  felt. 

254.  Again,  the  land  and  sea  breezes  in  Cuba,  and  along  the 
Gulf  shores  of  the  United  States,  will  be  more  regular  in  their  al- 
ternations than  they  are  along  the  shores  of  Brazil  or  South  Africa, 
and  for  the  simple  reason  that  the  shore-wind  named  in  North 
American  waters  lies  nearly  parallel  with  the  course  of  the  winds 
in  their  prevailing  direction.  In  Hio  de  Janeiro,  the  sea-breeze 
is  the  regular  trade-wind  made  fresher  by  the  daily  action  of  the 
sun  on  the  land.  It  is  worthy  of  remark,  also,  that,  for  the  rea- 
son stated  by  Jansen,  the  land  and  sea  breezes  in  the  winter  time 
are  almost  unknown  in  countries  of  severe  cold,  though,  in  the 
summer,  the  alternation  of  wind  from  land  to  sea,  and  sea  to  land, 
may  be  well  marked. 

255.  In  Valparaiso,  the  phenomenon  of  the  sea-breeze  is  finely 
developed.  Valparaiso  is  situated  near  the  southern  border  of  the 
calm  belt  of  Capricorn  when  it  is  at  its  farthest  southern  reach, 
which  happens  in  our  late  winter  and  early  spring — the  Southern 
summer  and  autumn.  This  is  the  dry  season,  wdien  the  sky  is 
singularly  clear  and  bright.     The  atmosphere,  being  nearly  in  a 


112  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

state  .of  equilibrium,  is  then  ready  to  obey  even  the  most  feeble 
impulse,  and  to  hasten  toward  the  place  of  any,  the  slightest  rare- 
faction. 

256.  At  about  ten  in  the  morning,  at  this  season  of  the  year, 
the  land  begins  to  feel  the  sun,  an-d  there  is  a  movement  in  the 
air.  By  3  or  4  P.M.,  the  sea-breeze  comes  rushing  in  from  the 
southward  and  westward,  and  strikes  the  shipping  in  the  harbor 
with  the  force  of  a  gale.  Vessels  sometimes  drag  before  it,  and 
communication  with  the  shore  is  suspended.  By  6  P.M.,  how- 
ever, the  wind  has  spent  its  fury,  and  there  is  a  perfect  calm.] 

)  257.  "Happy  he,"  continues  Jansen,  "who,  in  the  Java  Sea 
at  evening,  seeking  the  land-breeze  off  the  coast,  finds  it  there, 
after  the  salt-bearing,  roaring  sea-wind,  and  can,  in  the  magnifi- 
cent nights  of  the  tropics,  breathe  the  refreshing  land-breeze,  oft- 
times  laden  with  delicious  odors.* 

258.  "  The  veil  of  clouds,  either  after  a  squall,  with  or  without 
rain,  or  after  the  coming  of  the  land-breeze,  is  speedily  withdrawn, 
and  leaves  the  sky  clearer  during  the  night,  only  now  and  then 
flecked  with  dark  clouds  floating  over  from  the  land.  Without 
these  floating  clouds  the  land-breeze  is  feeble.  When  the  clouds 
float  away  from  the  sea,  the  land-breeze  does  not  go  far  out  from 
the  coast,  or  is  wholly  replaced  by  the  sea-breeze,  or,  rather,  by 
the  trade-wind.  If  the  land-breeze  continues,  then  the  stars  loom 
forth,  as  if  to  free  themselves  from  the  dark  vault  of  the  heavens, 
but  their  light  does  not  wholly  vanquish  its  deep  blue,  which 
causes  the  cold  sacks  to  come  out  more  distinctly  near  the 
Southern  Gross,  as  it  smiles  consolingly  upon  us,  while  Scorpio, 
the  emblem  of  the  tropical  climate,  stands  like  a  warning  in  the 
heavens.  The  starlight,  which  is  reflected  by  the  mirrored  waters, 
causes  the  nights  to  vie  in  clearness  with  the  early  twilight  in 
high  latitudes.  Numerous  shooting  stars  weary  the  eye,  although 
they  break  the  monotony  of  the  sparkling  firmament.  Their  un- 
ceasing motion  in  the  unfathomable  ocean  aflbrds  a  great  contrast 
to  the  seeming  quiet  of  the  gently-flowing  aerial  current  of  the 
land-breeze.  But  at  times,  when,  30°  or  40°  above  the  horizon, 
a  fire-ball  arises  which  suddenly  illumines  the  whole  horizon,  ap- 
*  In  the  roads  of  Batavia,  however,  they  are  not  very  agreeable. — Jansen. 


LAND  AND  SEA  BREEZES.  113 

pcarlng  to  the  eye  the  size  of  the  fist,  and  fading  away  as  sud- 
denly as  it  appeared,  falling  into  fiery  nodules,  then  we  perceive 
that,  in  the  apparent  calm  of  nature,  various  forces  are  constantly 
active,  in  order  to  cause,  even  in  the  invisible  air,  such  combina- 
tions and  combustions,  the  appearance  of  which  amazes  the  crews 
of  ships. 

259.  "  When  the  slender  keel  glides  quickly  over  the  mirrored 
waters  upon  the  wings  of  the  wind,  it  cuts  for  itself  a  sj^arkling 
way,  and  disturbs  in  their  sleep  the  monsters  of  the  deep,  which 
whud  and  dart  quicker  than  an  eight-knot  ship ;  sweeping  and  turn- 
ing around  their  disturber,  they  suddenly  clothe  the  dark  surface 
of  the  water  in  brilliancy.  Again,  when  we  go  beyond  the  limits 
of  the  land-breeze,  and  come  into  the  continuous  trade-wind,  we 
occasionally  see  from  the  low-moving,  round  black  clouds  (unless 
it  thunders),  light  blue  sparks  collected  upon  the  extreme  points 
of  the  iron  belaying-pins,  etc.  ;*  then  the  crew  appear  to  fear  a  new 
danger,  against  which  courage  is  unavailing,  and  which  the  mind 
can  find  no  power  to  endure.  The  fervent,  fiery  nature  inspires 
the  traveler  with  deep  awe.  They  who,  under  the  beating  of  the 
storm  and  terrible  violence  of  the  ocean,  look  danger  courageously 
in  the  face,  feel,  in  the  presence  of  these  phenomena,  insignificant, 
feeble,  anxious.  Then  they  perceive  the  mighty  power  of  the 
Creator  over  the  works  of  his  creation. 

260.  "And  how  can  the  uncertain,  the  undetermined  sensations 
arise  which  are  produced  by  the  clear  yet  sad  light  of  the  moon  ? 
she  who  has  always  great  tears  in  her  eyes,  while  the  stars  look 
sweetly  at  her,  as  if  they  loved  to  trust  her  and  to  share  her  af- 
fliction.! 

261.  "In  the  latter  part  of  the  night,  the  land-breeze  sinks  to 
sleep,  for  it  seldom  continues  to  blow  with  strength,  but  is  always 
fickle  and  capricious.     "With  the  break  of  day  it  again  awakes,  to 

*  I  have  seen  this  in  a  remarkable  degree  upon  the  south  coast  of  Java ;  these 
sparks  were  then  seen  six  feet  above  the  deck,  upon  the  frames  of  timber  {kousscn  dcr 
hlokkcn),  in  the  implements,  etc. — Jansen. 

t  Some  one  has  ventured  the  remark  that  at  full  moon,  near  the  equator,  more  and 
darker  dew  falls  than  at  new  moon,  and  to  this  are  ascribed  the  moonheads  {maan 
hoofdcn),  which  I  have  seen,  however,  but  once  during  all  the  years  which  I  have  spent 
between  the  tropics. — Jansen. 


114  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

sport  a  while,  and  then  gradually  dies  away  as  the  sun  rises. 
The  time  at  which  it  becomes  calm  after  the  land  and  sea  breezes 
is  indefinite,  and  the  calms  are  of  unequal  duration. 

262.  "  Generally,  those  which  precede  the  sea-breeze  are  rather 
longer  than  those  which  precede  the  land-breeze.  The  tempera- 
ture of  the  land,  the  direction  of  the  coast-line  with  respect  to  the 
prevailing  direction  of  the  trade-wind  in  which  the  land  is  situ- 
ated, the  clearness  of  the  atmosphere,  the  position  of  the  sun, 
perhaps  also  that  of  the  moon,  the  surface  over  which  the  sea- 
breeze  blows,  possibly  also  the  degree  of  moisture  and  the  elec- 
trical state  of  the  air,  the  heights  of  the  mountains,  their  extent, 
and  their  distance  from  the  coast,  all  have  influence  thereon. 
Local  observations  in  regard  to  these  can  afford  much  light,  as 
well  as  determine  the  distance  at  which  the  land-breeze  blows 
from  the  coast,  and  beyond  which  the  regular  trade-wind  or  mon- 
soon continues  uninterruptedly  to  blow.  The  direction  of  land 
and  sea  winds  must  also  be  determined  by  local  observations, 
for  the  idea  is  incorrect  that  they  should  always  blow  perpendic- 
ular to  the  coast-line. 

263.  "  Scarcely  has  one  left  the  Java  Sea — which  is,  as  it  were, 
an  inland  sea  between  Sumatra,  Borneo,  Java,  and  the  archipelago 
of  small  islands  between  both  of  the  last  named — than,  in  the  blue 
waters  of  the  easterly  part  of  the  East  Indian  Archipelago,  nature 
assumes  a  bolder  aspect,  more  in  harmony  with  the  great  depth 
of  the  ocean.  The  beauty  of  the  Java  Sea,  and  the  delightful 
phenomena  which  air  and  ocean  display,  have  here  ceased.  The 
scene  becomes  more  earnest.  The  coasts  of  the  eastern  islands 
rise  boldly  out  of  the  w\T-ter,  far  in  whose  depths  they  have  plant- 
ed their  feet.  The  southeast  wind,  which  blows  upon  the  south- 
ern coasts  of  the  chain  of  islands,  is  sometimes  violent,  always 
strong  through  the  straits  which  separate  them  from  each  other, 
and  this  appears  to  be  more  and  more  the  case  as  we  go  eastward. 
Here,  also,  upon  the  northern  coast,  we  find  land-breezes,  yet  the 
trade-wind  often  blows  so  violently  that  they  have  not  sufficient 
power  to  force  it  beyond  the  coast. 

264.  "Owing  to  the  obstruction  which  the  chain  of  islands  pre- 
sents to  the  southeast  trade-wind,  it  happens  that  it  blows  with 


LAND  AND  SEA^  BREEZES.  -  115 

violence  away  over  the  mountains,  apparently  as  tlie  land-breeze 
does  upon  the  north  coast  ;*  yet  this  wind,  which  only  rises  when 
it  blovv^s  hard  from  the  southeast  upon  the  south  coast,  is  easily 
distinguished  from  the  gentle  land-breeze. 

265.  "  The  regularity  of  the  land  and  sea  breezes  in  the  Java 
Sea  and  upon  the  coasts  of  the  northern  range  of  islands,  Banca, 
Borneo,  Celebes,  etc.,  during  the  east  monsoon,  must,  in  part,  be 
ascribed  to  the  hinderances  which  the  southeast  trade-wind  meets 
in  the  islands  which  lie  directly  in  its  way — in  part  to  the  inclina- 
tion toward  the  east  monsoon  which  the  trade-wind  underg-oes  aft- 
er  it  has  come  within  the  archipelago — and,  finally,  to  its  abate- 
ment as  it  approaches  the  equator.  The  causes  which  produce 
the  land-breezes  thus  appear  collectively  not  sufficiently  powerful 
to  be  able  to  turn  back  a  strong  trade- wind  in  the  ocean." 

*  Such  is  the  case,  among  others,  in  the  Strait  Madura,  upon  the  heights  of  Be» 
zoekie. 

H 


116  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTEE  V. 


EED  FOGS  AND  SEA  DUST. 


Where  found,  ^  266.— Tallies  on  the  Wmd,  272.— Where  taken  up,  278.— Humboldt's 
Description,  282. — Questions  to  be  answered,  284. — Wliat  Effects  the  Deserts  have 
upon  the  General  Circulation  of  the  Air,  286. — Information  derived  from  Sea  Dust, 
288. — Limits  of  Trade-winds,  289. — Breadth  of  Calm  Belts,  290. 

266.  Seamen  tell  us  of  "red  fogs"  wliicli  they  sometimes  en- 
counter, especially  in  the  vicinity  of  the  Cape  de  Verd  Islands. 
In  other  parts  of  the  sea  also  they  meet  showers  of  dust.  What 
these  showers  precipitate  in  the  Mediterranean  is  called  "  sirocco 
dust,"  and  in  other  parts  "  African  dust,"  because  the  winds  which 
accompany  them  are  supposed  to  come  from  the  Sirocco  desert,  or 
some  other  parched  land  of  the  continent  of  Africa.  It  is  of  a 
brick-red  or  cinnamon  color,  and  it  sometimes  comes  down  in  such 
quantities  as  to  cover  the  sails  and  rigging,  though  the  vessel  may 
he  hundreds  of  miles  from  the  land. 

267.  Now  the  patient  reader,  who  has  had  the  heart  to  foUow 
me  in  the  preceding  chapter  around  with  "  the  wind  in  his  cir- 
cuits," will  perceive  that  proof  is  yet  wanting  to  establish  it  as  a 
fact  that  the  northeast  and  southeast  trades,  after  meeting  and  ris- 
ing up  in  the  equatorial  calms,  do  cross  over  and  take  the  paths 
represented  by  C  and  G,  Plate  I. 

268.  Statements,  and  reasons,  and  arguments  enough  have  al- 
ready been  made  and  adduced  to  make  it  highly  probable,  accord- 
ing to  human  reasoning,  that  such  is  the  case  ;  and  though  the 
theoretical  deductions  showing  such  to  be  the  case  be  never  so 
plausible,  positive  proof  that  they  are  true  can  not  fail  to  be  re- 
ceived with  delight  and  satisfaction. 

269.  Were  it  possible  to  take  a  portion  of  this  air,  representing, 
as  it  travels  along  with  the  southeast  trades,  the  general  course  of 
atmospherical  circulation,  and  to  put  a  tally  on  it  by  which  we 
could  foUow  it  in  its  circuits  and  always  recognize  it,  then  we 


RED  FOGS  AND  SEA  DUST.  nj 

might  hope  actuallj  to  prove,  by  evidence  the  most  positive,  the 
channels  through  which  the  air  of  the  trade-winds,  after  ascending 
at  the  equator,  returns  whence  it  came. 

270.  But  the  air  is  invisible ;  and  it  is  not  easily  perceived  how 
either  marks  or  tallies  may  be  put  upon  it,  that  it  may  be  traced 
in  its  paths  through  the  clouds.  The  skeptic,  therefore,  who  finds 
it  hard  to  believe  that  the  general  circulation  is  such  as  Plate  I. 
represents  it  to  be,  might  consider  himself  safe  in  his  unbelief 
were  he- to  declare  his  willingness  to  give  it  up  the  moment  any 
one  should  put  tallies  on  the  wings  of  the  wind,  which  would  en- 
able him  to  recognize  that  air  again,  and  those  tallies,  when  found 
at  other  parts  of  the  earth's  surface. 

271.  As  difficult  as  this  seems  to  be,  it  has  actually  been  done. 
Ehrenberg,  with  his  microscope,  has  established,  almost  beyond  a 
doubt,  that  the  air  which  the  southeast  trade-winds  bring  to  the 
equator  does  rise  up  there  and  pass  over  into  the  northern  hemi- 
sphere. 

272.  The  Sirocco,  or  African  dust,  which  he  has  been  observ- 
ing so  closely,  has  turned  out  to  be  tallies  put  upon  the  wind  in 
the  other  hemisphere ;  and  this  beautiful  instrument  of  his  ena- 
bles us  to  detect  the  marks  on  these  little  tallies  as  plainly  as 
though  those  marks  had  been  written  upon  labels  of  wood  and  tied 
to  the  w^ngs  of  the  wind. 

273.  This  dust,  when  subjected  to  microscopic  examination,  is 
found  to  consist  of  infusoria  and  organisms  whose  habitat  is  not 
Africa,  but  South  America,  and  in  the  southeast  trade-wind  region 
of  South  America.  Professor  Ehrenberg  has  examined  specimens 
of  sea  dust  from  the  Cape  de  Verds  and  the  regions  thereabout, 
from  Malta,  Genoa,  Lyons,  and  the  Tyrol ;  and  he  has  found  a 
similarity  among  them  as  striking  as  it  would  have  been  had  these 
specimens  been  all  taken  from  tlie  same  pile.  South  American 
forms  he  recognizes  in  all  of  them ;  indeed,  they  are  the  prevail- 
ing forms  in  every  specimen  he  has  examined. 

274.  It  may,  I  think,  be  now  regarded  as  an  established  fact, 
that  there  is  a  perpetual  upper  current  of  air  from  South  America 
to  North  Africa ;  and  that  the  volume  of  air  which  flows  to  the 
northward  in  these  upper  currents  is  nearly  equal  to  the  volume 


118  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

which  flows  to  the  southward  with  the  northeast  trade-winds, 
there  can  be  no  doubt. 

275.  The  "rain  dust"  has  been  observed  most  frequently  to 
fall  in  spring  and  autumn ;  that  is,  the  fall  has  occurred  after  the 
equinoxes,  but  at  intervals  from  them  varying  from  thirty  to  sixty 
days,  more  or  less.  To  account  for  this  sort  of  periodical  occur- 
rence of  the  falls  of  this  dust,  Ehrenberg  thinks  it  "  necessary  to 
suppose  a  dust-cloud  to  he  held  constantly  swimmAng  in  the  at- 
mosphere  hy  continuous  currents  of  ah%  ccnd  lying  in  the  region 
of  the  trade-winds^  hut  suffering  jpartial  and  periodical  devia- 
tions.^'' 

276.  It  has  already  been  shown  (§  188)  that  the  rain  or  calm 
belt  between  the  trades  travels  up  and  down  the  earth  from  north 
to  south,  making  the  rainy  season  wherever  it  goes.  The  reason 
of  this  will  be  explained  in  another  place. 

277.  This  dust  is  probably  taken  up  in  the  dry,  and  not  in  the 
wet  season;  instead,  therefore,  of  its  being  "held  in  clouds  suf- 
fering partial  and  periodical  deviations,"  as  Ehrenberg  suggests, 
it  more  probably  comes  from  one  place  about  the  vernal,  and  from 
another  about  the  autumnal  equinox ;  for  places  which  have  their 
rainy  season  at  one  equinox  have  their  dry  season  at  the  other. 

278.  At  the  time  of  the  vernal  equinox,  the  valley  of  the  Lower 
Oronoco  is  then  in  its  dry  season — every  thing  is  parched  up  with 
the  drought ;  the  pools  are  dry,  and  the  marshes  and  plains  be- 
come arid  wastes.  All  vegetation  has  ceased  ;  the  great  serpents 
and  reptiles  have  buried  themselves  for  hibernation  ;*  the  hum  of 
insect  life  is  hushed,  and  the  stillness  of  death  reigns  through  tlie 
valley. 

Under  these  circumstances,  the  light  breeze,  raising  dust  from 
lakes  that  are  dried  up,  and  lifting  motes  from  the  brown  savan- 
nas, will  bear  them  away  like  clouds  in  the  air. 

279.  This  is  the  period  of  the  year  when  the  surface  of  the  earth 
in  this  region,  strewed  with  impalpable  and  feather-light  remains 
of  animal  and  vegetable  organisms,  is  swept  over  by  whirlwinds, 
gales,  and  tornadoes  of  terrific  force ;  this  is  the  period  for  the 
general  atmospheric  disturbances  which  have  made  characteristic 

*  Humboldt. 


RED  FOGS  AND  SEA  DUST. 


119 


the  equinoxes.  Do  not  these  conditions  appear  sufficient  to  afford 
the  "  rain  dust"  for  the  spring  showers  ? 

280.  At  the  period  of  the  autumnal  equinox,  another  portion  of 
the  Amazonian  basin  is  parched  with  drought,  and  liable  to  winds 
that  fill  the  air  with  dust,  and  with  the  remains  of  dead  animal 
and  vegetable  matter;  these  impalpable  organisms,  which  each 
rainy  season  caUs  into  being,  to  perish  the  succeeding  season  of 
drought,  are  perhaps  distended  and  made  even  lighter  by  the  gas- 
es of  decomposition  which  has  been  going  on  in  the  period  of 
drouo'ht. 

o 

281.  May  not,  therefore,  the  whirlwinds  which  accompany  the 
•  vernal  equinox,  and  sweep  over  the  lifeless  plains  of  the  Lower 

Oronoco,  take  up  the  "  rain  dust"  which  descends  in  the  northern 
hemisphere  in  April  and  [May  ?  and  may  it  not  be  the  atmospher- 
ical disturbances  which  accompany  the  autumnal  equinox  that  take 
up  the  microscopic  organisms  from  the  Upper  Oronoco  and  the 
great  Amazonian  basin  for  the  showers  of  October  ? 

282.  The  Baron  von  Humboldt,  in  his  Aspects  qfJVature,  thus 
contrasts  the  wet  and  the  dry  seasons  there : 

"When,  under  the  vertical  rays  of  the  never-clouded  sun,  the 
carbonized  turfy  covering  falls  into  dust,  the  indurated  soil  cracks, 
asunder  as  if  from  the  shock  of  an  earthquake.  If  at  such  times 
two  opposing  currents  of  air,  whose  conflict  produces  a  rotary  mo- 
tion, come  in  contact  with  the  soil,  the  plain  assumes  a  strano-e 
and  singular  aspect.  Like  conical-shaped  clouds,  the  points  of 
which  descend  to  the  earth,  the  sand  rises  through  the  rarefied  air 
on  the  electrically-charged  centre  of  the  whirling  current,  resem- 
bling the  loud  water-spout,  dreaded  by  the  experienced  mariner. 
The  lowering  sky  sheds  a  dim,  almost  straw-colored  light  on  the 
desolate  plain.  The  horizon  draws  suddenly  nearer,  the  steppe 
seems  to  contract,  and  with  it  the  heart  of  the  wanderer.  The 
hot,  dusty  particles  which  fill  the  air  increase  its  suffocating  heat, 
and  the  east  wind,  blowing  over  the  long-heated  soil,  brings  with  it 
no  refreshment,  but  rather  a  still  more  burning  glow.  The  pools 
which  the  yellow,  fading  branches  of  the  fan-palm  had  protected 
from  evaporation,  now  gradually  disappear.  As  in  the  icy  north 
the  animals  become  torpid  with  cold,  so  here,  under  the  influence 


120  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

of  the  parching  drought,  the  crocodile  and  the  boa  become  mo- 
tionless and  fall  asleep,  deeply  buried  in  the  dry  mud 

"  The  distant  palm-bush,  apparently  raised  by  the  influence  of 
the  contact  of  unequally  heated  and  therefore  unequally  dense 
strata  of  air,  hovers  above  the  groun*d,  from  which  it  is  separated 
by  a  narrow  intervening  margin.  Half-concealed  by  the  dense 
clouds  of  dust,  restless  with  the  pain  of  thirst  and  hunger,  the 
horses  and  cattle  roam  around,  the  cattle  lowing  dismally,  and 
the  horses  stretching  out  their  long  necks  and  snuffing  the  wind, 
if  haply  a  moister  current  may  betray  the  neighborhood  of  a  not 
wholly  dried-up  pool 

"At  length,  after  the  long  drought,  the  welcome  season  of  the 
rain  arrives ;  and  then  how  suddenly  is  the  scene  changed !  .  .  .  . 

"Hardly  has  the  surface  of  the  earth  received  the  refreshing 
moisture,  when  the  previously  barren  steppe  begins  to  exhale 
sweet  odors,  and  to  clothe  itself  with  killingias,  the  many  pani- 
cles of  the  paspulum,  and  a  variety  of  grasses.  The  lierbaceous 
mimosas,  with  renewed  sensibility  to  the  influence  of  light,  unfold 
their  drooping,  slumbering  leaves  to  greet  the  rising  sun ;  and  the 
early  song  of  birds  and  the  opening  blossoms  of  the  water  plants 
join  to  salute  the  morning." 

283.  The  arid  plains  and  deserts,  as  well  as  high  mountain 
ranges,  have,  it  may  well  be  supposed,  an  influence  upon  the 
movements  of  the  great  aerial  ocean,  as  shoals  and  other  obstruc- 
tions have  upon  the  channels  of  circulation  in  the  sea.  The  des- 
erts of  Asia,  for  instance,  produce  (§  203)  a  disturbance  upon  the 
grand  system  of  atmospherical  circulation,  which,  in  summer  and 
autumn,  is  felt  in  Europe,  in  Liberia,  and  away  out  upon  the  In- 
dian Ocean,  as  far  to  the  south  as  the  equinoctial  line.  There  is 
an  indraught  from  all  these  regions  toward  these  deserts.  These 
indraughts  are  known  as  monsoons  at  sea;  on  the  land,  as  the 
prevailing  winds  of  the  season. 

284.  Imagine  the  area  within  which  this  indraught  is  felt,  and 
let  us  ask  a  question  or  two,  hoping  for  answers.  The  air  which 
the  indraught  brings  into  the  desert  places,  and  which,  being  heat- 
ed, rises  up  there,  whither  does  it  go  ?  It  rises  up  in  a  column  a 
few  miles  high  and  many  in  circumference,  we  know,  and  we  can 


RED  FOGS  AND  SEA  DUST.  121 

imagine  that  it  is  like  a  shaft  many  times  thicker  than  it  is  tall, 
but  how  is  it  crowned  ?  Is  it  crowned  like  the  stem  ol  a  mush- 
room, with  an  efflorescence  or  ebullition  of  heated  air  flaring  over 
and  spreading  out  in  all  directions,  and  then  gradually  thinning 
out  as  an  upper  current,  extending  even  unto  the  verge  of  the  area 
whence  the  indraught  is  drawn  ?  If  so,  does  it  then  descend  and 
return  to  the  desert  plains  as  an  indraught  again  ?  Then  these 
desert  places  would  constitute  centres  of  circulation  for  the  mon- 
soon period ;  and  if  they  were  such  centres,  whence  would  these 
winds  get  the  vapor  for  their  rains  in  Europe  and  Asia  ? 

285.  Or,  instead  of  the  mushroom  shape,  and  the  flare  at  the 
top  in  all  directions  from  centre  to  circumference,  does  the  upris- 
ing column,  like  one  of  those  submarine  fountains  which  are  said 
to  be  in  the  Gulf  Stream  off  the  coast  of  Florida,  bubble  up  and 
join  in  with  the  flow  of  the  upper  current  ?  The  right  answers 
and  explanations  to  these  questions  would  add  greatly  to  our 
knowledge  concerning  the  general  circulation  of  the  atmosphere. 
It  may  be  in  the  power  of  the  microscope  to  give  light  here.  Let 
us  hope. 

286.  The  color  of  the  "rain  dust,"  when  collected  in  parcels 
atid  sent  to  Ehrenberg,  is  "  brick-red,"  or  "yellow  ochre ;"  when 
seen  by  Humboldt  in  the  air,  it  was  less  deeply  shaded,  and  is 
described  hy  Jiim  as  imparting  a  "  straw  color"  to  the  atmosphere. 
In  the  search  of  spider  lines  for  the  diaphragm  of  my  telescopes,  I 
procured  the  finest  and  best  tlireads  from  a  cocoon  of  a  mud-red 
color ;  but  the  threads  of  this  cocoon,  as  seen  singly  in  the  dia- 
phragm, were  of  a  golden  color;  there  would  seem,  therefore,  no  dif- 
ficulty in  reconciling  the  difference  between  the  colors  of  the  rain 
dust  when  viewed  in  little  piles  by  the  microscopist,  and  when 
seen  attenuated  and  floating  in  the  wind  by  the  great  traveler. 

287.  It  appears,  therefore,  that  we  here  have  placed  in  our  hands 
a  clew,  which,  attenuated  and  gossamer-like  though  it  at  first  ap- 
pears, is  nevertheless  palpable  and  strong  enough  to  guide  us  along 
through  the  "circuits  of  the  wind"  even  unto  "the  chambers  of 
the  south." 

288.  The  frequency  of  the  fall  of  "rain  dust"  between  the  par- 
allels of  17°  and  25°  north,  and  in  the  vicinity  of  the  Cape  Verd 


122       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

Islands,  is  remarked  upon  with  emphasis  hy  the  microscopist.  It 
is  worthy  of  remark,  because,  in  connection  with  the  investigations 
at  the  Observatory,  it  is  significant. 

289.  The  latitudinal  limits  of  the  northern  edge  of  the  north- 
east trade-winds  are  variable.  In  the  spring  they  are  nearest  to 
the  equator,  extending  sometimes  at  this  season  not  farther  from 
the  equator  than  the  parallel  of  15°  north. 

290.  The  breadth  of  the  calms  of  Cancer  is  also  variable  ;  so 
also  are  their  limits.  The  extreme  vibration  of  this  zone  is  be- 
tween the  parallels  of  17°  and  38°  north,  according  to  the  season 
of  the  year. 

291.  According  to  the  hypothesis  (§  130)  suggested  by  my  re- 
searches, this  is  the  zone  in  which  the  upper  currents  of  atmos- 
phere that  ascended  in  the  equatorial  calms,  and  flowed  off  to  the 
northward  and  eastward,  are  supposed  to  descend.  This,  there- 
fore, is  the  zone  in  which  the  atmosphere  that  bears  the  "rain 
dust,"  or  "African  sand,"  descends  to  the  surface ;  and  this,  there- 
fore, is  the  zone,  it  might  be  supposed,  which  would  be  the  most 
liable  to  showers  of  this  "  dust."  This  is  the  zone  in  which  the 
Cape  Verd  Islands  are  situated ;  they  are  in  the  direction  which 
theory  gives  to  the  upper  current  of  air  from  the  Oronoco  and  Am- 
azon with  its  "  rain  dust,"  and  they  are  in  the  region  of  the  most 
frequent  showers  of  "rain  dust,"  all  of  which,  though  they  do  not 
absolutely  prove,  are  nevertheless  strikingly  in  conformity  with, 
this  theory  as  to  the  circulation  of  the  atmosphere. 

292.  It  is  true  that,  in  the  present  state  of  our  information,  we 
can  not  tell  why  this  "rain  dust"  should  not  be  gradually  precip- 
itated from  this  upper  current,  and  descend  into  the  stratum  of 
trade-winds,  as  it  passes  from  the  equator  to  higher  northern  lat- 
itudes ;  neither  can  we  tell  why  the  vapor  which  the  same  winds 
carry  along  should  not,  in  like  manner,  be  precipitated  on  the  way ; 
nor  why  we  should  have  a  thunder-storm,  a  gale  of  wind,  or  the 
display  of  any  other  atmospherical  phenomenon  to-morrow,  and 
not  to-day  :  all  that  we  can  say  is,  that  the  conditions  of  to-day 
are  not  such  as  the  phenomenon  requires  for  its  own  development. 

293.  Therefore,  though  we  can  not  tell  why  the  "  sea  dust" 
should  not  fall  always  in  the  same  place,  we  may  nevertheless  sup- 


RED  FOGS  AND  SEA  DUST.  123 

pose  that  it  is  not  always  in  the  atmosphere,  for  the  storms  that 
take  it  up  occur  onlj  occasionally,  and  that  when  up,  and  in  pass- 
ing the  same  parallels,  it  does  not,  any  more  than  the  vapor  from  a 
given  part  of  the  sea,  always  meet  with  the  conditions — electrical 
and  others— favorable  to  its  descent,  and  that  these  conditions,  as 
with  the  vapor,  may  occur  now  in  this  place,  now  in  that.  But 
that  the  fall  does  occur  always  in  the  same  atmospherical  vein  or 
general  direction,  my  investigations  would  suggest,  and  Ehren- 
herg's  researches  prove. 

294.  Judging  by  the  fall  of  sea  or  rain  dust,  we  may  suppose 
that  the  currents  in  the  upper  regions  of  the  atmosphere  are  re- 
markable for  their  general  regularity,  as  well  as  for  their  general 
direction  and  sharpness  of  limits,  so  to  speak. 

295.  We  may  imagine  that  certain  electrical  conditions  are  nec- 
essary to  a  shower  of  "  sea  dust"  as  well  as  to  a  thunder-storm ; 
and  that  the  interval  between  the  time  of  the  equinoctial  disturb- 
ances in  the  atmosphere  and  the  occurrence  of  these  showers, 
though  it  does  not  enable  us  to  determine  the  true  rate  of  motion 
in  the  general  system  of  atmospherical  circulation,  yet  assures  us 
that  it  is  not  less  on  the  average  than  a  certain  rate. 

296.  I  do  not  offer  these  remarks  as  an  explanation  with  which 
we  ought  to  rest  satisfied,  provided  other  proof  can  be  obtained ; 
I  rather  offer  them  in  the  true  philosophical  spirit  of  the  distin- 
guished microscopist  himself,  simply  as  affording,  as  far  as  they 
are  entitled  to  be  called  an  explanation,  that  explanation  which  is 
most  in  conformity  with  the  facts  before  us,  and  which  is  suggest- 
ed by  the  results  of  a  novel  and  beautiful  system  of  philosophical 
research.  It  is  not,  however,  my  province,  or  that  of  any  other 
philosopher,  to  dictate  belief.  Any  one  may  found  hypotheses  if 
he  will  state  his  facts  and  the  reasoning  by  which  he  derives  the 
conclusions  which  constitute  the  hypothesis.  Having  done  this, 
he  should  patiently  wait  for  time,  farther  research,  and  the  judg- 
ment of  his  peers,  to  expand,  confirm,  or  reject  the  doctrine  which 
he  may  have  conceived  it  his  duty  to  proclaim. 

297.  Thus,  though  we  have  tallied  the  air,  and  put  labels  on 
tlie  wind,  to  "  tell  whence  it  cometh  and  whither  it  goeth,"  yet 
there  evidently  is  an  agent  concerned  in  the  circulation  of  the  at- 


124       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

mosphere  whose  functions  are  manifest,  but  whose  presence  has 
never  yet  been  clearly  recognized. 

298.  When  the  air  which  the  northeast  trade-winds  bring  down 
meets  in  the  equatorial  calms  that  which  the  southeast  trade-winds 
convey,  and  the  two  rise  up  together,  what  is  it  that  makes  them 
cross  ?  where  is  the  power  that  guides  that  from  the  north  over 
to  the  south,  and  that  from  the  south  up  to  the  north  ? 

The  conjectures  in  the  next  chapter  as  to  "  the  relation  between 
magnetism  and  the  circulation  of  the  atmosphere"  may  perhaps 
throw  some  light  upon  the  answer  to  this  question. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      125 


CHAPTEE  VL 

ON  THE   PEOBABLE  EELATION   BETWEEN   MAGNETISM  AND  THE 
CIECULATION   OF   THE    ATMOSPHEEE. 

Faraday's  Discoveries,  <$»  299. — Is  there  a  crossing  of  Air  at  the  Calm  Belts'!  301. — 
Whence  comes  the  Vapor  for  Rains  in  extra-tropical  Regions  1  305. — Significant 
Facts,  310. — Wet  and  dry  Winds,  311. — Regions  of  Precipitation  and  Evaporation, 
312. — What  guides  the  Wind  in  his  Circulations  1  313. — Distribution  of  Rains  and 
Winds  not  left  to  Chance,  315. — A  Conjecture  about  Magnetism,  318. — Circum- 
stantial Evidence,  323.  —  More  Evaporating  Surface  in  the  Southern  than  in  the 
Northern  Hemisphere,  326. — Whence  come  the  Vapors  that  feed  the  great  Rivers 
with  Rains  1  329. — Rain  and  Thermal  Maps,  330. — The  Dry  Season  in  California, 
the  Wet  in  the  Mississippi  Valley,  332. — Importance  of  Meteorological  Observations 
in  British  America,  333. — Importance  of  extending  the  System  from  the  Sea  to  the 
Land,  334. — Climate  of  the  Interior,  335. — The  extra-tropical  Regions  of  the  North- 
ern Hemisphere  Condenser  for  the  Trade-winds  of  the  Southern,  336. — Plate  VII., 
339. — Countries  most  favorable  for  having  Rains,  343. — How  does  the  Air  of  the 
Northeast  and  Southeast  Trades  cross  in  the  Equatorial  Calms,  350. — Rain  for  the 
Mississippi  Valley,  357. — Blood  Rains,  372. — Track  of  the  Passat-Staub  on  Plate 
VII.,  374.— The  Theory  of  Ampere,  378.— Calm  Regions  about  the  Poles,  380.— 
The  Pole  of  maximum  Cold,  381. 

299.  Oxygen,  philosopliers  say,  comprises  one  fifth  part  of  the 
atmosphere,  and  Faraday  has  discovered  that  it  is  magnetic. 

This  discovery  presents  itself  to  the  mind  as  a  great  physical 
fact,  which  is  perhaps  to  serve  as  the  keystone  for  some  of  the 
grand  and  "beautiful  structures  which  philosophy  is  building  up  for 
monuments  to  the  genius  of  the  age. 

300.  Certain  facts  and  deductions  elicited  in  the  course  of  these 
investigations  had  directed  my  mind  to  the  workings  in  the  at- 
mosphere of  some  agent,  as  to  whose  character  and  nature  I  was 
ignorant.  Heat,  and  the  diurnal  rotation  of  the  earth  on  its  axis, 
were  not,  it  appeared  to  me,  sufficient  to  account  for  all  the  cur- 
rents of  both  sea  and  air  which  investigation  was  bringing  to  light. 

301.  For  instance,  there  was  reason  to  suppose  that  there  is  a 
crossing  of  winds  at  the  three  calm  belts  ;  that  is,  that  the  south- 
east trade-winds,  when  they  arrive  at  the  belt  of  equatorial  calms 


126  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

and  ascend,  cross  over  and  continue  their  course  as  an  upper  cur- 
rent to  the  calms  of  Cancer,  while  the  air  that  the  northeast  trade- 
winds  discharge  into  the  equatorial  calm  belt  continues  to  go  south, 
as  an  upper  current  bound  for  the  calms  of  Capricorn.  But  what 
should  cause  this  wind  to  cross  over .?  Why  should  there  not  be 
a  general  mingling  in  this  calm  belt  of  the  air  brought  by  the  two 
trade-winds,  and  why  should  not  that  which  the  southeast  winds 
convey  there  be  left,  after  its  ascent,  to  flow  off  either  to  the  north 
or  to  the  south,  as  chance  directs  ? 

302.  In  the  first  place,  it  was  at  variance  with  my  faith  in  the 
grand  design ;  for  I  could  not  bring  myself  to  believe  that  the  op- 
erations of  such  an  important  machine  as  the  atmosphere  should 
be  left  to  chance,  even  for  a  moment.  Yet  I  knew  of  no  agent 
which  should  guide  the  wind  across  these  calm  belts,  and  lead  it 
out  always  on  the  side  opposite  to  that  on  which  it  entered ;  nev- 
ertheless, certain  circumstances  seemed  to  indicate  that  such  a 
crossing  does  take  place.- 

303.  Evidence  in  favor  of  it  seemed  to  be  afforded  by  this  cir- 
cumstance, viz.,  our  researches  enabled  us  to  trace  from  the  belt 
of  calms,  near  the  tropic  of  Cancer,  which  extends  entirely  across 
the  seas,  an  eflEux  of  air  both  to  the  north  and  to  the  south ;  from 
the  south  side  of  this  belt  the  air  flows  in  a  never-ceasing  breeze, 
called  the  northeast  trade-winds,  toward  the  equator.     (Plate  I.) 

On  the  north  side  of  it,  the  prevailing  winds  come  from  it  also, 
but  they  go  toward  the  northeast.  They  are  the  well-known  south- 
westerly winds  which  prevail  along  the  route  from  this  country  to 
England,  in  the  ratio  of  two  to  one.  But  why  should  we  suppose 
a  crossing  to  take  place  here  ? 

304.  We  suppose  so,  because  these  last-named  winds  are  going 
from  a  warmer  to  a  colder  climate,  and  therefore  it  may  be  infer- 
red that  nature  exacts  from  them  what  we  know  she  exacts  from 
the  air  under  similar  circumstances,  but  on  a  smaller  scale,  before 
our  eyes,  viz.,  more  precipitation  than  evaporation. 

305.  But  where,  it  may  be  asked,  does  the  vapor  which  these 
winds  carry  along,  for  the  replenishing  of  the  whole  extra-tropical 
regions  of  the  north,  come  from  ?  They  did  not  get  it  as  they 
came  along  in  the  upper  regions,  a  counter-current  to  the  north- 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      127 

east  trades,  unless  they  evaporated  the  trade-wind  clouds,  and  so 
robbed  those  winds  of  their  vapor.  They  certainly  did  not  get  it 
from  the  surface  of  the  sea  in  the  calm  belt  of  Cancer,  for  they 
did  not  tarry  long  enough  there  to  become  saturated  with  moisture. 
Thus  circumstances  again  pointed  to  the  southeast  trade-wind  re- 
gions as  the  place  of  supply. 

306.  Moreover,  these  researches  afforded  grounds  for  the  sup- 
position that  the  air  of  which  the  northeast  trade-winds  are  com- 
posed, and  which  comes  out  of  the  same  zone  of  calms  as  do  these 
southwesterly  winds,  so  far  from  being  saturated  v/ith  vapor  at  its 
exodus,  is  dry ;  for  near  their  polar  edge,  the  northeast  trade- 
winds  are,  for  the  most  part,  dry  winds.  Eeason  suggests,  and 
philosophy  teaches,  that,  going  from  a  lower  to  a  higher  tempera- 
tm'e,  the  evaporating  powers  of  these  winds  are  increased ;  that 
they  have  to  travel,  in  their  oblique  course  toward  the  equator, 
a  distance  of  nearly  three  thousand  miles  ;  that,  as  a  general  rule, 
they  evaporate  all  the  time,  and  all  the  way,  and  precipitate  little 
or  none  on  their  route ;  investigations  have  proved  that  they  are 
not  saturated  with  moisture  until  they  have  arrived  fully  up  to 
the  regions  of  equatorial  calms,  a  zone  of  constant  precipitation. 

This  calm  zone  of  Cancer  borders  also,  it  was  perceived,  upon 
a  rainy  region. 

307.  Where  does  the  vapor  which  here,  on  the  northern  edge 
of  this  zone  of  Cancer,  is  condensed  into  rains,  come  from? — 
and  Avhere,  also — was  the  oft-repeated  question — does  the  vapor 
which  is  condensed  into  rains  for  the  extra-tropical  regions  of 
the  north  generally  come  from  ?  By  what  agency  is  it  conveyed 
across  this  calm  belt  from  its  birth-place  between  the  tropics  ? 

308.  I  know  of  no  law  of  nature  or  rule  of  j)hilosophy  which 
would  forbid  the  supposition  that  the  air  which  has  been  brought 
along  as  the  northeast  trade-winds  to  the  equatorial  calms  does, 
after  ascending  there,  return  by  the  counter  and  upper  currents 
to  the  calm  zone  of  Cancer,  here  descend  and  reappear  on  the 
sm-face  as  the  northeast  trade-winds  again.  I  know  of  no  agent 
in  nature  which  would  jprevent  it  from  taking  this  circuit,  nor  do 
I  know  of  any  which  would  compel  it  to  take  this  circuit ;  but 
while  I  know  of  no  agent  in  nature  that  would  prevent  it  from 


128  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

taking  this  circuit,  I  know,  on  the  other  hand,  of  circumstances 
which  rendered  it  probable  that  such,  in  general,  is  not  the  course 
of  atmospherical  circulation — that  it  does  not  take  this  circuit.  I 
speak  of  the  rule,  not  of  the  exceptions ;  these  are  infinite,  and, 
for  the  most  part,  are  caused  by  the  land. 

309.  And  I  moreover  know  of  facts  which  go  to  strengtiien 
the  supposition  that  the  winds  which  have  corne  in  the  upper 
regions  of  the  atmosphere  from  the  equator,  do  not,  after  arriving 
at  the  calms  of  Cancer,  and  descending,  return  to  the  equator  on 
the  surface,  but  that  they  continue  on  the  surface  toward  the  pole. 
But  why  should  they  ?  What  agent  in  nature  is  there  that  can 
compel  these,  rather  than  any  other  winds,  to  take  such  a  circuit? 

310.  The  following  are  some  of  the  facts  and  circumstances 
which  give  strength  to  the  supposition  that  these  winds  do  con- 
tinue from  the  calm  belt  of  Cancer  tov/ard  the  pole  as  the  prevail- 
ing southwesterly  winds  of  the  extra-tropical  north : 

"We  have  seen  (Plate  I.)  that,  on  the  north  side  of  this  calm 
zone  of  Cancer,  the  prevailing  winds  on  the  surface  are  from  this 
zone  toward  the  pole,  and  that  these  winds  return  as  A  through 
the  upper  regions  from  the  pole ;  that,  arriving  at  the  calms  of 
Cancer,  this  upper  current  A  meets  another  upper  current  Gr  from 
the  equator,  where  they  neutralize  each  other,  produce  a  calm, 
descend,  and  come  out  as  surface  winds,  viz.,  A  as  B,  or  the  trade- 
winds  ;  and  G  as  H,  or  the  variable  winds. 

311.  Now  observations  have  shown  that  the  winds  represented 
by  H  are  rain  winds ;  those  represented  by  B,  dry  winds  ;  and  it 
is  evident  that  A  could  not  bring  any  vapors  to  these  calms  to 
serve  for  H  to  make  rains  of ;  for  the  winds  represented  by  A  have 
already  performed  the  circuit  of  surface  winds  as  far  as  the  pole, 
during  which  journey  they  parted  with  all  their  moisture,  and,  re- 
turning through  the  upper  regions  of  the  air  to  the  calm  belt  of 
Cancer,  they  arrived  there  as  dry  winds.  The  winds  represented 
by  B  are  dry  winds ;  therefore  it  was  supposed  that  these  are  but 
a  continuation  of  the  winds  A. 

312.  On  the  other  hand,  if  the  winds  A,  after  descending,  do 
turn  about  and  become  the  surface  winds  H,  they  would  first  have 
to  remain  a  long  time  in  contact  with  the  sea,  in  order  to  be  sup- 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      129 

plied  with  vapor  enough  to  feed  the  great  rivers,  and  supply  the 
rains  for  the  whole  earth  between  us  and  the  north  pole.  In  this 
case,  we  should  have  an  evaporating  region  on  the  north  as  well 
as  on  the  south  side  of  this  zone  of  Cancer ;  hut  investigation 
shows  no  such  region ;  I  speak  exclusively  of  the  ocean. 

313.  Hence  it  was  inferred  that  A  and  G  do  come  out  on  the 
surface  as  represented  by  Plate  I.  But  what  is  the  agent  that 
should  lead  them  out  by  such  opposite  paths  ? 

314.  According  to  this  mode  of  reasoning,  the  vapors  which 
supply  the  rains  for  H  would  be  taken  up  in  the  southeast  trade- 
wind  region  by  F,  and  conveyed  thence  along  the  route  G  to  H. 
And  if  this  mode  of  reasoning  be  admitted  as  plausible — if  it  be 
true  that  G  have  the  vapor  which,  by  condensation,  is  to  water 
with  showers  the  extra-tropical  regions  of  the  northern  hemisphere, 
Nature,  we  may  be  sure,  has  provided  a  guide  for  conducting  G 
across  this  belt  of  calms,  and  for  sending  it  on  in  the  right  way. 
Here  it  was,  then,  at  this  crossing  of  the  winds,  that  I  thought  I 
first  saw  the  foot-prints  of  an  agent  whose  character  I  could  not 
comprehend.  Could  it  be  the  magnetism  that  resides  in  the  oxy- 
gen of  the  air  ? 

315.  Heat  and  cold,  the  early  and  the  latter  rain,  clouds  and 
sunshine,  are  not,  we  may  rely  upon  it,  distributed  over  the  earth 
by  chance ;  they  are  distributed  in  obedience  to  laws  that  are  as 
certain  and  as  snre  in  their  operations  as  the  seasons  in  their 
rounds.  If  it  depended  upon  chance  whether  the  dry  air  should 
come  out  on  this  side  or  on  that  of  this  calm  belt,  or  whether  the 
moist  air  should  return  or  not  whence  it  came — if  such  were  the 
case  in  nature,  we  perceive  that,  so  far  from  any  regularity  as  to 
seasons,  we  should  have,  or  might  have,  years  of  droughts  the 
most  excessive,  and  then  again  seasons  of  rains  the  most  destruct- 
ive ;  but,  so  far  from  this,  we  find  for  each  place  a  mean  annual 
proportion  of  both,  and  that  so  regulated  withal,  that  year  after 
year  the  quantity  is  preserved  with  remarkable  regularity. 

316.  Having  thus  shown  that  there  is  no  reason  for  supposing 
that  the  upper  currents  of  air,  when  they  meet  over  the  calms  of 
Cancer  and  Capricorn,  are  turned  back  to  the  equator,  but  having 
shown  that  there  is  reason  for  supposing  that  the  air  of  each  cur- 


130       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

rent,  after  descending,  continues  on  in  the  direction  toward  wliicli 
it  was  traveling  before  it  descended,  we  may  go  farther,  and,  by 
a  similar  train  of  circumstantial  evidence,  afforded  by  these  re- 
searches and  other  sources  of  information,  show  that  the  air,  kept 
in  motion  on  the  surface  by  the  two -systems  of  trade- winds,  when 
it  arrives  at  the  belt  of  equatorial  calms,  and  ascends,  continues 
on  thence,  each  current  toward  the  pole  which  it  was  approaching 
while  on  the  surface. 

317.  In  a  problem  like  this,  demonstration  in  the  positive  way 
is  difficult,  if  not  impossible.  We  must  rely  for  our  proof  upon 
philosophical  deduction,  guided  by  the  lights  of  reason ;  and  in 
all  cases  in  which  positive  proof  can  not  be  adduced,  it  is  permit- 
ted to  bring  in  circumstantial  evidence. 

318.  I  am  endeavoring,  let  it  be  borne  in  mind,  to  show  cause 
for  the  conjecture  that  the  magnetism  of  the  oxygen  of  the  atmos- 
phere is  concerned  in  conducting  the  air  which  has  blown  as  the 
southeast  trade-winds — and  after  it  has  arrived  at  the  belt  of  equa- 
torial calms  and  risen  up — over  into  the  northern  hemisphere,  and 
so  on  through  its  channels  of  circulation,  as  traced  on  Plate  I. 

319.  But,  in  order  to  show  reasonable  grounds  for  this  conjec- 
ture, I  want  to  establish,  by  circumstantial  evidence  and  such  in- 
direct proof  as  my  investigations  afford,  that  such  is  the  course 
of  the  "wind  in  his  circuits,"  and  that  the  winds  represented  by 
F,  Plate  L,  do  become  those  represented  by  G,  H,  A,  B,  C,  D, 
and  E  successively. 

320.  In  tlie  first  place,  F  represents  the  southeast  trade-winds 
— i.  e.,  all  the  winds  of  the  southern  hemisphere  as  they  approach 
the  equator ;  and  is  there  any  reason  for  supposing  that  the  atmos- 
phere does  not  pass  freely  from  one  hemisphere  to  another  ?  On 
the  contrary,  many  reasons  present  themselves  for  supposing  that 
it  does. 

321.  If  it  did  not,  the  proportion  of  land  and  water,  and  con- 
sequently of  plants  and  warm-blooded  animals,  being  so  different 
in  tlie  two  hemispheres,  we  might  imagine  that  the  constituents 
of  the  atmosphere  in  them  would,  in  the  course  of  ages,  probably 
become  different,  and  that  consequently,  in  such  a  case,  man  could 
not  safely  pass  from  one  hemisphere  to  the  other. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      13I 

322.  Consider  the  manifold  beauties  in  the  whole  system  of 
terrestrial  adaptations ;  remember  what  a  perfect  and  wonderful 
machine  (§  169)  is  this  atmosphere  ;  how  exquisitely  balanced  and 
beautifully  compensated  it  is  in  all  its  parts.  We  know  that  it  is 
perfect ;  that  in  the  performance  of  its  various  offices  it  is  never 
left  to  the  guidance  of  chance — no,  not  for  a  moment.  Therefore 
I  was  led  to  ask  myself  why  the  air  of  the  southeast  trades,  when 
arrived  at  the  zone  of  equatorial  calms,  should  not,  after  ascend- 
ing, rather  return  to  the  south  than  go  on  to  the  north  ?  Where 
and  what  is  the  agency  by  which  its  course  is  decided  ? 

323.  Here  I  found  circumstances  which  again  induced  me  to 
suppose  it  probable  that  it  neither  turned  back  to  the  south  nor 
mingled  with  the  air  which  came  from  the  regions  of  the  north- 
east trades,  ascended,  and  then  flowed  indiscriminately  to  the 
north  or  the  south. 

324.  But  I  saw  reasons  for  supposing  that  what  came  to  the 
equatorial  calms  as  the  southeast  trade-winds  continued  to  the 
north  as  an  upper  current,  and  that  what  had  come  to  the  same 
zone  as  northeast  trade-winds  ascended  and  continued  over  into 
the  southern  hemisphere  as  an  upper  current,  bound  for  the  calm 
zone  of  Capricorn. 

And  these  are  the  principal  reasons  and  conjectures  upon  which 
these  suppositions  were  based : 

325.  At  the  seasons  of  the  year  when  the  area  covered  by  the 
southeast  trade-winds  is  large,  and  when  they  are  evaporating 
most  rapidly  in  the  southern  hemisphere,  even  up  to  the  equator, 
the  most  rain  is  falling  in  the  northern.  Therefore  it  is  fair  to 
suppose  that  much  of  the  vapor  which  is  taken  up  on  that  side  of 
the  equator  is  precipitated  on  this. 

326.  The  evaporating  surface  in  the  southern  hemisphere  is 
greater,  much  greater,  than  it  is^  in  the  northern ;  still,  all  the 
great  rivers  are  in  the  northern  hemisphere,  the  Amazon  being 
regarded  as  common  to  both  ;  and  this  fact,  as  far  as  it  goes,  tends 
to  corroborate  the  suggestion  as  to  the  crossing  of  the  trade- winds 
at  the  equatorial  calms. 

327.  Independently  of  other  sources  of  information,  my  inves- 
tigations also  taught  me  to  believe  that  the  mean  temperature  of 

I 


132  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

tlie  tropical  regions  was  liiglier  in  the  northern  than  in  the  southern 
hemisphere ;  for  they  show  that  the  difference  is  such  as  to  draw 
the  equatorial  edge  of  the  southeast  trades  far  over  on  this  side 
of  the  equator,  and  to  give  them  force  enough  to  keep  the  north- 
east trade-winds  out  of  the  southern  hemisphere  almost  entirely. 

328.  Consequently,  as  before  stated,  the  southeast  trade-winds 
being  in  contact  with  a  more  extended  evaporating  surface,  and 
continuing  in  contact  with  it  for  a  longer  time  or  through  a  greater 
distance,  they  would  probably  arrive  at  the  trade-wind  place  of 
meeting  more  heavily  laden  with  moisture  than  the  others. 

329.  Taking  the  laws  and  rates  of  evaporation  into  considera- 
tion, I  could  find  no  part  of  the  ocean  of  the  northern  hemisphere 
from  which  the  sources  of  the  Mississippi,  the  St.  Lawrence,  and 
the  other  great  rivers  of  our  hemisphere  could  be  supplied. 

330.  A  resiular  series  of  meteoroloQ-ical  observations  has  been 
carried  on  at  the  military  posts  of  the  United  States  since  1819. 
E-ain  maps  of  the  whole  country*  have  been  prepared  from  these 
observations  by  Mr.  Lorin  Blodget  at  the  surgeon  general's  office, 
and  under  the  direction  of  Dr.  Cooledge,  U.  S.  A.  These  maps, 
as  far  as  they  go,  sustain  these  views  in  a  remarkable  manner ;  for 
they  bring  out  facts  in  a  most  striking  way  to  show  that  the  dry 
season  in  California  and  Orearon  is  the  wet  season  in  the  Missis- 

o 
sippi  Valley. 

331.  The  winds  coming  from  the  southwest,  and  striking  upon 
the  coasts  of  California  and  Oregon  in  winter,  precipitate  there 
copiously.  They  then  pass  over  the  mountains  robbed  in  part 
of  their  moisture.  Of  course,  after  watering  the  Pacific  shores, 
they  have  not  as  much  vapor  to  make  rains  of,  especially  for  the 
upper  Mississippi  Valley,  as  they  had  in  the  summer  time,  when 
they  dispensed  their  moisture,  in  the  shape  of  rains,  most  sparingly 
upon  the  Pacific  coasts. 

.  332.  According  to  these  views,  the  dry  season  on  the  Pacific 
slopes  should  be  the  wet,  especially  in  the  upper  Mississippi  Val- 
ley, and  vice  versa.  Blodget's  maps  show  that  such  is  actually 
the  case. 

333.  Meteorological  observations  in  the  "  E.ed  River  country" 

*  See  Army  Meteorological  Observations,  published  1855. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPPIERE.      133 

and  other  parts  of  British  America  would  throw  farther  light  and 
give  farther  confirmation,  I  doubt  not,  both  to  these  views  and  to 
this  interesting  question. 

334.  These  army  observations,  as  expressed  in  Blodget's  maps, 
reveal  other  interesting  features,  also,  touching  the  physical  geoo*- 
raphj  of  the  country.  I  allude  to  the  two  isothermal  lines  45° 
and  65^  (Plate  VIII.),  which  include  between  them  all  places  that 
have  a  mean  annual  temperature  between  45°  and  65°. 

335.  I  have  drawn  similar  lines  on  the  authority  of  Dove  and 
Johnston  (A.  K.,  of  Edinburgh),  across  Europe  and  Asia,  for  the 
sake  of  comparison.  The  isotherm  of  65°  skirts  the  northern  lim- 
its of  the  sugar-cane,  and  separates  the  inter-tropical  from  the  extra- 
tropical  plants  and  productions.  I  have  drawn  these  two  lines 
across  America  in  order  to  give  a  practical  exemplification  of  the 
nature  of  the  advantages  which  the  industrial  pursuits  and  the 
political  economy  of  the  country  would  derive  by  the  systematic 
extension  of  our  meteorological  observations  from  the  sea  to  the 
land.  These  lines  show  how  much  we  err  when  we  reckon  cli- 
mates according  to  parallels  of  latitude.  The  space  that  these 
two  isotherms  of  45°  and  65°  comprehend  between  the  Missis- 
sippi and  the  Eocky  Mountains,  owing  to  the  singular  effect  of 
those  mountains  upon  the  climate,  is  larger  than  the  space  they 
comprehend  between  the  Mississippi  and  the  Atlantic. 

Hyetographically  it  is  also  different,  being  dryer,  and  possessing 
a  purer  atmosphere.  In  this  grand  range  of  climate  between  the 
meridians  of  100°  and  110°  W.,  the  amount  of  ^precipitation  is 
just  about  one  half  of  what  it  is  between  those  two  isotherms  east 
of  the  Mississippi.  In  this  new  country  west  of  it,  winter  is  the 
dry,  and  spring  the  rainy  season.  It  includes  the  climates  of  the 
Caspian  Sea,  which  Humboldt  regards  as  the  most  salubrious  in 
the  world,  and  where  he  found  the  most  delicious  fruits  that  he 
saw  during  his  travels.  Such  was  the  purity  of  the  air  there, 
that  polished  steel  would  not  tarnish  even  by  night  exposure. 
These  two  isotherms,  with  the  remarkable  loop  which  they  make 
to  the  northwest,  beyond  the  Mississippi,  embrace  the  most  choice 
climates  for  the  olive,  the  vine,  and  the  poppy ;  for  the  melon,  the 
peach,  and  almond.  The  finest  of  wool  may  be  grown  there,  and 
the  potato,  with  hemp,  tobacco,  maize,  and  all  the  cereals,  may  be 


134  THE  PPIYSICAL  GEOGRAPHY  OF  THE  SEA. 

cultivated  there  in  great  perfection.  No  climate  of  the  temperate 
zone  will  be  found  to  surpass  in  salubrity  that  of  this  Piedmont 
trans-Mississippi  country. 

336.  By  such  trains  of  thought  and  reasoning  as  are  here  sketch- 
ed, and  by  such  facts  and  circumstances  as  are  stated  above,  I 
have  been  brought  to  regard  the  extra-tropical  regions  of  the  north<- 
ern  hemisphere  as  standing  in  the  relation  of  a  condenser  to  a 
grand  steam  macliine  (§  168),  the  boiler  of  which  is  in  the  region 
of  the  southeast  trade-winds,  and  to  consider  the  trade-winds  of 
this  hemisphere  as  performing  the  like  office  for  the  regions  beyond 
Capricorn. 

337.  The  calm  zone  of  Capricorn  is  the  duplicate  of  that  of 
Cancer,  and  the  winds  flow  from  it  as  they  do  from  that,  both 
north  and  south ;  but  with  this  difference :  that  on  the  polar  side 
of  the  Capricorn  belt  they  prevail  from  the  northwest  instead  of 
the  southwest,  and  on  the  equatorial  side  from  the  southeast  in- 
stead of  the  northeast. 

338.  ISTow  if  it  be  true  that  the  vapor  of  the  northeast  trade- 
winds  is  condensed  in  the  extra-troj)ical  regions  of  the  southern 
hemisphere,  the  following  path,  on  account  of  the  effect  of  diurnal 
rotation  of  the  earth  upon  the  course  of  the  winds,  would  repre- 
sent the  mean  circuit  of  a  portion  of  the  atmosphere  moving  ac- 
cording to  the  general  system  of  its  circulation  over  the  Pacific 
Ocean,  viz.,  coming  down  from  the  north  as  an  upper  current,  and 
appearing  on  the  surface  of  the  earth  in  about  longitude  120° 
west,  and  near  the  tropic  of  Cancer,  it  would  here  commence  to 
blow  the  northeast  trade-winds  of  that  region. 

339.  To  make  this  clear,  see  Plate  VII.,  on  which  I  have  mark- 
ed the  course  of  such  vapor-bearing  winds  ;  A  being  a  breadth  or 
swath  of  winds  in  the  nortlieast  trades ;  B,  the  same  wind  as  the 
upper  and  counter-current  to  the  southeast  trades ;  and  C,  the 
same  wind  after  it  has  descended  in  the  calm  belt  of  Capricorn, 
and  come  out  on  the  polar  side  thereof,  as  the  rain  winds  and  pre- 
vailing northwest  winds  of  the  extra-tropical  regions  of  the  south- 
ern hemisphere. 

340.  This,  as  the  northeast  trades,  is  the  evaporating  wind. 
As  the  northeast  trade-wind,  it  sweeps  over  a  great  waste  of 
waters  lying  between  the  tropic  of  Cancer  and  the  equator. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      I35 

341.  Meeting  no  land  in  this  long  oblique  track  over  the  tepid 
waters  of  a  tropical  sea,  it  would,  if  such  were  its  route,  arrive 
somev/hsre  about  the  meridian  of  140°  or  150°  west,  at  the  belt 
of  equatorial  calms,  which  always  divides  the  northeast  from  the 
southeast  trade-winds.  Here,  depositing  a  portion  of  its  vapor  as 
it  ascends,  it  would,  with  the  residuum,  take,  on  account  of  diurnal 
rotation,  a  course  in  the  upper  region  of  the  atmosphere  to  the 
southeast,  as  far  as  the  calms  of  Capricorn.  Here  it  descends 
and  continues  on  toward  the  coast  of  South  America,  in  the  same 
direction,  appearing  now  as  the  prevailing  northwest  wind  of  the 
extra-tropical  regions  of  the  southern  hemisphere.  Traveling  on 
the  surface  from  warmer  to  colder  regions,  it  must,  in  this  part  of 
its  circuit,  precipitate  more  than  it  evaporates. 

342.  'Now  it  is  a  coincidence,  at  least,  that  this  is  the  route  by 
which,  on  account  of  the'  land  in  the  northern  hemisphere,  the 
northeast  trade-winds  have  the  fairest  sweep  over  that  ocean. 
This  is  the  route  by  which  they  are  longest  in  contact  with  an 
evaporating  surface ;  the  route  by  which  all  circumstances  are 
most  favorable  to  complete  saturation ;  and  this  is  the  route  by 
which  they  can  pass  over  into  the  southern  hemisphere  most 
heavily  laden  with  vapors  for  the  extra-tropical  regions  of  that 
half  of  the  globe  ;  and  this  is  the  supposed  route  which  the  north- 
east trade-Avinds  of  the  Pacific  take  to  reach  the  equator  and  to 
pass  from  it. 

343.  Accordingly,  if  this  process  of  reasoning  be  good,  that 
portion  of  South  America  between  the  calms  of  Capricorn  and 
Cape  Horn,  upon  the  mountain  ranges  of  which  this  part  of  the 
atmosphere,  whose  circuit  I  am  considering  as  a  type,  first  im- 
pinges, ought  to  be  a  region  of  copious  precipitation. 

344.  Now  let  us  turn  to  the  works  on  Physical  Geography, 
and  see  what  we  can  find  upon  tliis  subject.  In  Berghaus  and 
Johnston — department  Hyetography — it  is  stated,  on  the  authority 
of  Captain  King,  R.  N.,  that  upward  of  twelve  feet  (one  hundred 
and  fifty-three  inches)  of  rain  fell  in  forty-one  days  on  that  part 
of  the  coast  of  Patagonia  which  lies  within  the  sweep  of  the  winds 
just  described.  So  much  rain  falls  there,  navigators  say,  that  they 
sometimes  find  the  water  on.  the  top  of  the  sea  fresh  and  sweet. 


136  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

345.  After  impinging  upon  the  cold  hill-tops  of  the  Patagonian 
coast,  and  passing  the  snow-clad  summits  of  the  Andes,  this  same 
wind  tumbles  down  upon  the  eastern  slopes  of  the  range  as  a  dry 
wind ;  as  such,  it  traverses  the  almost  rainless  and  barren  regions 
of  cis-Andean  Patagonia  and  South  Buenos  Ajres. 

346.  These  conditions,  the  direction  of  the  prevailing  w^nds, 
and  the  amount  of  precipitation,  may  be  regarded  as  evidence  af- 
forded by  nature,  if  not  in  favor  of,  certainly  not  against,  the  con- 
jecture that  such  may  have  been  the  voyage  of  this  vapor  through 
the  air.  At  any  rate,  here  is  proof  of  the  immense  quantity  of 
vapor  which  these  winds  of  the  extra-tropical  regions  carry  along 
with  them  toward  the  poles ;  and  I  can  imagine  no  other  place 
than  that  suggested,  whence  these  winds  could  get  so  much  va- 
por. 

I  am  not  unaware  ol  the  theory,  or  of  the  weight  attached  to  it, 
which  requires  precipitation  to  take  place  in  the  upper  regions  of 
the  atmosphere  on  account  of  the  cold  there,  irrespective  of  prox- 
imity to  mountain  tops  and  snow-clad  hills. 

347.  But  the  facts  and  conditions  developed  by  this  system  of 
research  upon  the  high  seas  are  in  many  respects  irreconcilable 
with  that  theory.  With  a  new  system  of  facts  before  me,  I  have, 
independent  of  all  preconceived  notions  and  opinions,  set  about  to 
seek  among  them  for  explanations  and  reconciliations. 

348.  These  may  not  in  all  cases  be  satisfactory  to  every  one ; 
indeed,  notwithstanding  the  amount  of  circumstantial  evidence 
that  -has  already  been  brought  to  show  that  the  air  which  the 
northeast  and  the  southeast  trade-winds  discharge  into  the  belts 
of  equatorial  calms,  does,  in  ascending,  cross — that  from  the  south- 
ern passing  over  into  the  northern,  and  that  from  the  northern 
passing  over  into  the  southern  hemisphere  (see  F  and  G,  B  and 
C,  Plate  I.) — yet  some  have  implied  doubt  by  asking  the  ques- 
tion, "How  are  two  such  currents  of  air  to  pass  each  other?" 
And,  for  the  w^ant  of  light  upon  this  point,  the  correctness  of  rea- 
soning, facts,  inferences,  and  deductions  have  been  questioned. 

349.  In  the  first  place,  it  may  be  said  in  reply,  the  belt  of  equa- 
torial calms  is  often  several  lumdred  miles  across,  seldom  less  than 
sixty ;  whereas  the  depth  of  the  volume  of  air  that  the  trade- winds 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      I37 

pour  into  it  is  only  about  three  miles,  for  that  is  supposed  to  "be 
about  the  height  to  which  the  trade-winds  extend. 

350.  Thus  we  liave  the  air  passing  into  these  calms  by  an  open- 
ing on  the  north  side  for  the  northeast  trades,  and  another  on  the 
south  for  the  southeast  trades,  having  a  cross  section  of  three 
miles  vertically  to  each  opening.  It  then  escapes  by  an  opening 
upward,  the  cross  section  of  which  is  sixty  or  one  hundred,  or  even 
three  hundred  miles.  A  very  slow  motion  upward  there  will  car- 
ry off  the  air  in  that  direction  as  fast  as  the  two  systems  of  trade- 
winds,  with  their  motion  of  twenty  miles  an  hour,  can  pour  it  in ; 
and  that  curds  or  columns  of  air  can  readily  cross  each  other  and 
pass  in  different  directions  without  interfering  the  one  with  the 
other,  or  at  least  to  that  degree  Avhich  obstructs  or  prevents,  we 
all  know. 

351.  For  example,  open  the  window  of  a  warm  room  in  winter, 
and  immediately  there  are  two  currents  of  air  ready  at  once  to  set 
through  it,  viz.,  a  current  of  warm  air  flowing  out  at  the  top,  and 
one  of  cold  coming  in  below. 

352.  But  the  brown  fields  in  summer  afford  evidence  on  a  larger 
scale,  and  in  a  still  more  striking  manner,  of  the  fact  that,  in  na- 
ture, columns,  or  streamlets,  or  curdles  of  air  do  really  move  among 
each  other  without  obstruction.  That  tremulous  motion  which 
we  so  often  observe  above  stubble-fields,  barren  wastes,  or  above 
any  heated  surface,  is  caused  by  the  ascent  and  descent,  at  one 
and  the  same  time,  of  columns  of  air  at  different  temperatures,  the 
cool  coming  down,  the  warm  going  up.  They  do  not  readily  com- 
mingle, for  the  astronomer,  long  after  nightfall,  when  he  turns  his 
telescope  upon  the  heavens,  perceives  and  laments  the  unsteadi- 
ness they  produce  in  the  sky. 

353.  If  the  air  brought  down  by  the  northeast  trade-winds  dif- 
fer in  temperature  (and  why  not^?)  from  that  brought  by  the  south- 
east trades,  we  have  the  authority  of  nature  for  saying  that  the 
two  currents  would  not  readily  commingle.  Proof  is  daily  affords 
ed  that  they  would  not,  and  there  is  reason  to  believe  that  the  air 
of  each  current,  in  streaks,  or  patches,  or  curdles,  does  thread  its 
way  through  the  air  of  the  other  without  difficulty.  Now,  if  the 
air  of  these  two  currents  differs  as  to  magnetism,  might  not  that 


138  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

be  an  additional  reason  for  their  not  mixing,  and  for  their  taking 
the  direction  of  opposite  poles  after  ascending  ? 

354.  Therefore  we  may  assume  it  as  a  postulate  which  nature 
concedes,  that  there  is  no  difficulty  as  to  the  two  currents  of  air, 
which  come  into  those  calm  belts  from  different  directions,  cross- 
ing over,  each  in  its  23roper  direction,  without  mingling. 

355.  Thus,  having  shown  that  there  is  nothing  to  prevent  the 
crossing  of  the  air  in  these  calm  belts,  I  return  to  the  process  of 
reasoning  by  induction,  and  offer  additional  circumstantial  evi- 
dence to  prove  that  such  a  crossing  does  take  place.  Let  us  there- 
fore catechise,  on  this  head,  the  waters  which  the  Mississippi  pours 
into  the  sea,  inquiring  of  them  as  to  the  channels  among  the  clouds 
through  which  they  were  brought  from  the  ocean  to  the  fountains 
of  that  mighty  river. 

356.  It  rains  more  in  the  valley  drained  by  that  river  than  is 
evaporated  from  it  again.  The  difference  for  a  year  is  the  vol- 
ume of  water  annually  discharged  by  that  river  into  the  sea 
(§  165). 

357.  At  the  time  and  place  that  the  vapor  which  supplies  this 
immense  volume  of  water  was  lifted  by  the  atmosphere  up  from 
the  sea,  the  thermometer,  we  may  infer,  stood  higher  than  it  did 
at  the  time  and  place  where  this  vapor  was  condensed  and  fell 
down  as  rain  in  the  Missis sij)pi  Yalley. 

358.  I  looked  to  the  south  for  the  springs  in  the  Atlantic  which 
supply  the  fountains  of  this  river  with  rain.  But  I  could  not  find 
spare  evaporating  surface  enough  for  it,  in  the  first  place ;  and  if 
the  vapor,  I  could  not  find  the  winds  which  would  convey  it  thence 
to  the  right  place. 

359.  The  prevailing  winds  in  the  Caribbean  Sea  and  southern 
parts  of  the  Gulf  of  Mexico  are  the  northeast  trade-winds.  They 
have  their  offices  to  perform  in  the  river  basins  of  inter-tropical 
America,  and  the  rains  which  they  may  discharge  into  the  Missis- 
sippi Yalley  now  and  then  are  exceptions,  not  the  rule. 

360.  The  winds  from  the  north  can  not  bring  vapors  from  the 
great  lakes  to  make  rains  for  the  Mississippi,  for  two  reasons  : 
1st.  The  basin  of  the  great  lakes  receives  from  the  atmosphere 
more  water  in  the  shape  of  rain  than  they  give  back  in  the  shape 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      I39 

of  vapor.  The  St.  Lawrence  River  carries  off  the  excess.  2d. 
The  mean  climate  of  the  lake  country  is  colder  than  that  of  the 
Mississippi  Valley,  and  therefore,  as  a  general  rule,  the  tempera- 
ture of  the  Mississippi  Valley  is  unfavorable  for  condensing  vapor 
from  that  quarter. 

361.  It  can  not  come  from  the  Atlantic,  Ibecause  the  greater 
part  of  the  Mississippi  Valley  is  to  the  windward  of  the  Atlantic. 
The  winds  that  blow  across  this  ocean  go  to  Europe  with  their 
vapors  ;  and  in  the  Pacific,  from  the  parallels  of  California  down 
to  the  equator,  the  direction  of  the  wind  at  the  surface  is  from, 
not  toward  the  basin  of  the  Mississippi.  Therefore  it  seemed  to 
be  established  with  some  degree  of  probability,  or,  if  that  expres- 
sion be  too  strong,  with  something  like  apparent  plausibility,  that 
the  rain  winds  of  the  Mississippi  Valley  do  not,  as  a  general  rule, 
get  their  vapors  from  the  North  Atlantic  Ocean,  nor  from  the  Gulf 
of  Mexico,  nor  from  the  great  lakes,  nor  from  that  part  of  the  Pa- 
cific Ocean  over  which  the  northeast  trade-winds  prevail. 

362.  The  same  process  of  reasoning  which  conducted  us  (§  342) 
into  the  trade-wind  region  of  the  northern  hemisphere  for  the 
sources  of  the  Patagonian  rains,  now  invites  us  into  the  trade-wind 
regions  of  the  South  Pacific  Ocean  to  look  for  the  vapor  springs 
of  the  Mississippi. 

363.  If  the  rain  winds  of  the  Mississippi  Valley  come  from  the 
east,  then  we  should  have  reason  to  suppose  that  tlieir  vapors 
were  taken  up  from  the  Atlantic  Ocean  and  Gulf  Stream  ;  if  the 
rain  winds  come  from  the  south,  then  the  vapor  springs  might, 
perhaps,  be  in  the  Gulf  of  Mexico ;  if  the  rain  winds  come  from 
the  north,  then  the  great  lakes  might  be  supposed  to  feed  the  air 
with  moisture  for  the  fountains  of  that  river  ;  but  if  the  rains  come 
from  the  west,  where,  short  of  the  great  Pacific  Ocean,  should  we 
look  for  the  place  of  evaporation  ? 

Wondering  where,  I  addressed  a  circular  letter  to  farmers  and 
planters  of  the  Mississippi  Valley,  requesting  to  be  informed  as  to 
the  direction  of  their  rain  winds. 

364.  I  received  replies  from  Virginia,  Mississippi,  Tennessee, 
Missouri,  Indiana,  and  Ohio ;  and,  subsequently,  from  Col.  W.  A. 
Bird,  Buffalo,  New  York,  who  says,  "  The  southwest  winds  are 


140  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

our  fair-weather  winds  ;  we  seldom  have  rain  from  the  southwest." 
Buffalo  may  get  much  of  its  rain  from  the  Gulf  Stream  with  east- 
erly winds.  But  I  speak  of  the  Mississippi  Yalley  ;  all  the  re- 
spondents there,  with  the  exception  of  one  in  Missouri,  said,  "  The 
southwest  winds  bring  us  our  rains." 

365.  These  winds  certainly  can  not  get  their  vapors  from  the 
E-ocky  Mountains,  nor  from  the  Salt  Lake,  for  they  rain  quite  as 
much  upon  that  basin  as  they  evaporate  from  it  again ;  if  they  did 
not,  they  would,  in  the  process  of  time,  have  evaporated  all  the 
water  there,  and  the  lake  would  now  be  dry. 

366.  These  winds,  that  feed  the  sources  of  the  Mississippi  with 
rain,  like  those  between  the  same  parallels  upon  the  ocean,  are  go- 
ing from  a  higher  to  a  lower  temperature ;  and  these  winds  in  the 
Mississippi  Valley,  not  being  in  contact  with  the  ocean,  or  with 
any  other  evaporating  surface  to  supply  them  with  moisture,  must 
bring  with  them  from  some  sea  or  another  that  which  they  deposit. 

367.  Therefore,  though  it  may  be  urged,  inasmuch  as  the  winds 
which  brought  the  rains  to  Patagonia  (§  344)  came  direct  from  the 
sea,  that  they  therefore  took  up  their  vapors  as  they  came  along, 
yet  it  can  not  be  so  urged  in  this  case  ;  and  if  these  winds  could 
pass  with  their  vapors  from  the  equatorial  calms  through  the  upper 
regions  of  the  atmosphere  to  the  calms  of  Cancer,  and  then  as 
surface  winds  into  the  Mississippi  Yalley,  it  was  not  perceived 
why  the  Patagonian  rain  winds  should  not  bring  their  moisture  by 
a  similar  route.  These  last  are  from  the  northwest,  from  warmer 
to  colder  latitudes ;  therefore,  being  once  charged  with  vapors, 
they  must  precipitate  as  they  go,  and  take  up  less  moisture  than 
they  deposit.  The  circumstance  that  the  rainy  season  in  the  Mis- 
sissippi Valley  (§  330)  alternates  with  the  dry  season  on  the  coast 
of  California  and  Oregon,  indicates  that  the  two  regions  derive 
vapor  for  their  rains  from  the  same  fountains. 

368.  This,  however,  could  be  regarded  only  as  circumstantial 
evidence.  Not  a  fact  had  yet  been  elicited  to  prove  that  the 
course  of  atmospherical  circulation  suggested  by  my  investiga- 
tions is  the  actual  course  in  nature.  It  is  a  case  in  which  I  could 
yet  hope  for  nothing  more  direct  than  such  conclusions  as  might 
legitimately  flow  from  circumstances. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      141 

369.  My  friend  Lieutenant  De  Haven  was  about  to  sail  in  com- 
mand of  the  American  Arctic  Expedition  in  search  of  Sir  John 
Franklin.  Infusoria  are  sometimes  found  in  sea-dust,  rain-drops, 
hail-stones,  or  snow-flakes ;  and  if  by  any  chance  it  should  so 
turn  out  that  the  locus  of  any  of  the  microscopic  infusoria  which 
might  be  found  descending  with  the  precipitation  of  the  Arctic 
regions  should  be  identified  as  belonging  to  the  regions  of  the 
southeast  trade-winds,  we  should  thus  add  somewhat  to  the 
strength  of  the  many  clews  by  which  we  have  been  seeking  to 
enter  into  the  chambers  of  the  wind,  and  to  "  tell  whence  it  com- 
eth  and  whither  it  goeth." 

370.  It  is  not  for  man  to  follow  the  "wind  in  his  circuits;" 
and  all  that  could  be  hoped  was,  after  a  close  examination  of  all 
the  facts  and  circumstances  which  these  researches  upon  the  sea 
have  placed  within  my  reach,  to  point  out  that  course  which  seemed 
to  be  most  in  accordance  with  them  ;  and  then,  having  established 
a  probability,  or  even  a  possibility,  as  to  the  true  course  of  the 
atmospheric  circulation,  to  make  it  known,  and  leave  it  for  future 
investigations  to  confirm  or  set  aside. 

371.  It  was  at  this  stage  of  the  matter  that  my  friend  Baron 
von  Gerolt,  the  Prussian  minister,  had  the  kindness  to  place  in 
my  hand  Ehrenberg's  work,  "  Passat- Staub  und  Blut-Regen." 

Here  I  found  the  clew  which  I  hoped,  almost  against  hope,  De 
Haven  would  place  in  my  hands  (§  369)  from  the  north  pole. 

372.  That  celebrated  microscopist  reports  that  he  found  South 
American  infusoria  in  the  blood-rains  and  sea-dust  of  the  Cape 
Verd  Islands,  Lyons,  Genoa,  and  other  places  (§  273).   , 

373.  Thus  confirming,  as  far  as  such  evidence  can,  the  indica- 
tions of  our  observations,  and  increasing  the  probability  that  the 
general  course  of  atmospherical  circulation  is  in  conformity  with 
the  suggestions  of  the  facts  gathered  from  the  sea  as  I  had  inter- 
preted them,  viz.,  that  the  trade-winds  of  the  southern  hemisphere, 
after  arriving  at  the  belt  of  equatorial  calms,  ascend  and  continue 
in  their  course  toward  the  calms  of  Cancer  as  an  upper  cm-rent 
from  the  southwest,  and  that,  after  passing  this  zone  of  calms, 
they  are  felt  on  the  surface  as  the  prevailing  southwest  winds  of 
the  extra-tropical  parts  of  our  hemisphere ;  and  that,  for  the  most 


142       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

part,  thej  bring  their  moisture  with  them  from  the  trade-wind  re- 
gions of  the  opposite  hemisphere. 

374.  I  have  marked  on  Plate  YII.  the  supposed  track  of  the 
"Passat-Staub,"  showing  where  it  was  taken  up  in  South  Amer- 
ica, as  at  P,  P,  and  where  it  w^as  found,  as  at  S,  S ;  the  part  of 
the  line  in  dots  denoting  where  it  was  in  the  upper  current,  and 
the  unbroken  line  where  it  was  wafted  by  a  surface  current ;  also 
on  the  same  plate  is  designated  the  part  of  the  South  Pacific  in 
which  the  vapor-springs  for  the  Mississippi  rains  are  supposed  to 
be.  The  hands  (|^^)  point  out  the  direction  of  the  wind.  Where 
the  shading  is  light,  the  vapor  is  supposed  to  be  carried  by  an  up- 
per current. 

375.  Such  is  the  character  of  the  circumstantial  evidence  which 
induced  me  to  suspect  that  some  agent,  whose  office  in  the  grand 
system  of  atmospherical  circulation  is  neither  understood  nor  rec- 
ognized, was  at  work  in  these  calm  belts. 

376.  Dr.  Faraday  has  shown  that,  as  the  temperature  of  oxygen 
is  raised,  its  paramagnetic  force  diminishes,  being  resumed  as  the 
temperature  falls  again. 

"  These  properties  it  carries  into  the  atmosphere,  so  that  the 
latter  is,  in  reality,  a  magnetic  medium,  ever  varying,  from  the 
influence  of  natural  circumstances,  in  its  magnetic  power.  If  a 
mass  of  air  be  cooled,  it  becomes  more  paramagnetic ;  if  heated, 
it  becomes  less  paramagnetic  (or  diamagnetic),  as  compared  with 
the  air  in  a  mean  or  normal  condition."* 

377.  Now,  is  it  not  more  than  probable  that  here  we  have,  in 
the  magnetism  of  the  atmosphere,  that  agent  which  guides  the 
air  from  the  south  (§  373)  through  the  calms  of  Capricorn,  of  the 
equator,  and  of  Cancer,  and  conducts  it  into  the  north  ;  that  agent 
which  causes  the  atmosphere,  with  its  vapors  and  infusoria,  to  flow 
above  the  clouds  from  one  hemisphere  into  the  other,  and  whose 
footprints  had  become  so  palpable  ? 

378.  Taking  up  the  theory  of  Ampere  with  regard  to  the  mag- 
netic polarity  induced  by  an  electrical  current,  according  as  it 
passes  througli  wire  coiled  unth  or  coiled  against  the  sun,  and  ex- 

*  Philosophical  Magazine  and  Journal  of  Science,  4th  Series,  No.  I.,  January,  1851, 
page  73. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.     I43 

paneling  it  in  conformity  with  the  discoveries  of  Faraday  and  the 
experiments  of  a  Prussian  philosopher,*  we  perceive  a  series  of 
facts  and  principles  which,  being  applied  to  the  circulation  of  the 
atmosphere,  make  the  conclusions  to  which  I  have  been  led  touch- 
ing these  crossings  in  the  air,  and  the  continual  "  whirl"  of  the 
wind  in  the  Arctic  regions  against,  and  in  the  Antarctic  with  the 
hands  of  a  watch,  very  significant. 

379.  In  this  view  of  the  subject,  we  see  light  springing  up  from 
various  sources,  by  which  the  shadows  of  approaching  confirma- 
tion are  clearly  perceived.  One  such  source  of  light  conies  from 
the  observations  of  my  excellent  friend  Quetelet,  at  Brussels,  which 
show  that  the  great  electrical  reservoir  of  the  atmosphere  is  in  the 
upper  regions  of  the  air.  It  is  filled  with  positive  electricity, 
which  increases  as  the  temperature  diminishes. 

380.  May  we  not  look,  therefore,  to  find  about  the  north  and 
south  magnetic  poles  these  atmospherical  nodes  or  calm  regions 
which  I  have  theoretically  pointed  out  there  ?  In  other  words, 
are  not  the  magnetic  poles  of  the  earth  in  those  atmospherical 
nodes,  the  two  standing  in  the  relation  of  cause  and  effect,  the  one 
to  the  other  ? 

This  question  was  first  asked  several  years  ago,t  and  I  was 
then  moved  to  propound  it  by  the  inductions  of  theoretical  rea- 
soning. 

381.  Observers,  perhaps,  will  never  reach  those  inhospitable 
regions  with  their  instruments  to  shed  light  upon  this  subject ; 
but  Parry  and  Barrow  have  found  reasons  to  believe  in  the  exist- 
ence of  a  perpetual  calm  about  the  north  pole,  and,  later,  Bellot 
has  reported  the  existence  of  a  calm  region  within  the  frigid  zone. 
Professor  J.  H.  Coffin,  in  an  elaborate  and  valuable  paperj  on  the 
"Winds  of  the  Northern  Hemisphere,"  arrives  by  deduction 
at  a  like  conclusion.  In  that  paper  he  has  discussed  the  records 
at  no  less  than  five  hundred  and  seventy-nine  meteorological  sta- 
tions, embracing  a  totality  of  observations  for  two  thousand  eight 
hundred  and  twenty-nine  years.     He  places  his  "meteorological 

*  Professor  Von  Feilitzsch,  of  the  University  of  Griefswald.     Philosophical  Maga- 
zine, January,  1851.  t  Maury's  Sailing  Directions. 
\  Smithsonian  Contributions  to  Knowledge,  vol.  vi.,  1854. 


144       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

pole" — pole  of  the  winds — near  latitude  84°  north,  longitude  105^ 
west.  The  pole  of  maximum  cold,  by  another  school  of  philoso- 
phers, Sir  David  Brewster  among  them,  has  been  placed  in  lati- 
tude 80°  north,  longitude  100°  west ;  and  the  magnetic  pole,  by 
still  another  school,*  in  latitude  73®  35"  north,  longitude  95°  39' 

west. 

382.  Neither  of  these  poles  is  a  point  susceptible  of  definite 
and  exact  position.  The  polar  calms  are  no  more  a  point  than  the 
equatorial  calms  are  a  line ;  and,  considering  that  these  poles  are 
areas  or  discs,  not  points,  it  is  a  little  curious  that  philosophers  in 
different  parts  of  the  world,  using  different  data,  and  following  up 
investigation  each  through  a  separate  and  independent  system  of 
research,  and  each  aiming  at  the  solution  of  different  problems, 
should  nevertheless  agree  in  assigning  very  nearly  the  same  posi- 
tion to  them  all?  Are  these  three  poles  grouped  together  by 
chance,  or  by  some  physical  cause  ?  By  the  latter,  undoubtedly. 
Here,  then,  we  have  another  of  those  gossamer-like  clews,  that 
sometimes  seem  almost  palpable  enough  for  the  mind,  in  its  hap- 
piest mood,  to  lay  hold  of,  and  follow  up  to  the  very  portals  of 
knowledge,  where,  pausing  to  knock,  we  may  boldly  demand  that 
the  chambers  of  hidden  things  be  thrown  wide  open,  that  we  may 
see  and  understand  the  mysteries  of  the  winds,  the  frost,  and  the 
trembling  needle. 

383.  In  the  polar  calms  there  is  (§  139)  an  ascent  of  air;  if  an 
ascent,  a  diminution  of  pressure  and  an  expansion ;  and  if  expan- 
sion, a  decrease  of  temperature.  Therefore  we  have  palpably 
enough  a  connecting  link  here  between  the  polar  calms  and  the 
polar  place  of  maximum  cold.  Thus  we  establish  a  relation  be- 
tween the  pole  of  the  winds  and  the  pole  of  cold,  with  evident  in- 
dications that  there  is  also  a  physical  connection  between  these 
and  the  magnetic  pole.  Here  the  outcroppings  of  the  relation 
between  magnetism  and  the  circulation  of  the  atmosphere  again 
appear. 

384.  May  we  not  find  in  such  evidence  as  this,  threads,  atten- 
uated and  almost  air  drawn  though  they  be  when  taken  singly 
and  alone,  yet  nevertheless  proving,  when  brought  together,  to 

*  Gauss. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      I45 

have  a  consistency  sufficient,  with  the  lights  of  reason,  to  guide 
us  as  we  seek  to  trace  the  wind  in  his  circuits?  The  winds  ap- 
proach these  polar  calms  (§  155)  by  a  circular  or  spiral  motion, 
traveling  in  the  northern  hemisphere  against^  and  in  the  southern 
vnth  the  hands  of  a  watch.  The  circular  gales  of  the  northern 
hemisphere  are  said  also  to  revolve  in  like  manner  against  the 
hands  of  a  watch,  while  those  in  the  southern  hemisphere  tj-avel 
the  other  way.  Kow,  should  not  this  discovery  of  these  three 
poles,  this  coincidence  of  revolving  winds,  with  the  other  circum- 
stances that  have  been  brought  to  light,  encourage  us  to  look  to 
the  magnetism  of  the  air  for  the  key  to  these  mysterious  but 
striking  coincidences  ? 

385.  Indeed,  so  wide  is  the  field  for  speculation  presented  by 
these  discoveries,  that  we  may  in  some  respects  regard  this  gTcat 
globe  itself,  with  its  "  cups"  and  spiral  wires  of  air,  earth,  and 
water,  as  an  immense  "  pile"  and  helix,  which,  being  excited  by 
the  natural  batteries  in  the  sea  and  atmosphere  of  the  tropics,  ex- 
cites in  turn  its  oxygen,  and  imparts  to  atmospherical  matter  the 
properties  of  magnetism. 

386.  With  the  lights  which  these  discoveries  cast,  we  see  (Plate 
I.)  why  air,  which  has  completed  its  circuit  to  the  whirl*  about  the 
Antarctic  regions,  should  then,  according  to  the  laws  of  magnet- 
ism, be  repelled  from  the  south,  and  attracted  by  the  opposite  pole 
toward  the  north. 

387.  And  when  the  southeast  and  the  northeast  trade-winds 
meet  in  the  equatorial  calms  of  the  Pacific,  would  not  these  mag- 
netic forces  be  sufficient  to  determine  the  course  of  each  current, 
bringing  the  former,  with  its  vapors  of  the  southern  hemisphere, 
over  into  this,  by  the  courses  already  suggested  ? 

388.  This  force  and  the  heat  of  the  sun  would  propel  it  to  the 
north.  The  diurnal  rotation  of  the  earth  propels  it  to  the  east ; 
consequently,  its  course,  first  through  the  upper  regions  of  the 
atmosphere,  and  then  on  the  .su.rface  of  the  earth,  after  being 
conducted  by  this  newly-discovered  agent  across  the  calms  of 
Cancer,  would  be  from  the  southward  and  westward  to  the  north- 
ward and  eastward. 

*  "  It  whirleth  about  coHtinually." — BihU. 


146  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

389.  These  are  the  winds  (§  181)  which,  on  their  way  to  the 
north  from  the  South  Pacific,  would  pass  over  the  Mississippi 
Valley,  and  they  appear  (§  364)  to  be  the  rain  winds  there. 
Whence,  then,  if  not  from  the  trade-wind  regions  of  the  South 
Pacific,  can  the  vapors  for  those  rains  come  ? 

390.  According  to  this  view,  and  not  taking  into  account  any 
of  the  exceptions  produced  by  the  land  and  other  circumstances 
upon  tlie  general  circulation  of  the  atmosphere  over  the  ocean,  the 
southeast  trade-winds,  which  reach  the  shores  of  Brazil  near  the 
parallel  of  Kio,  and  which  blow  thence  for  the  most  part  over  the 
land,  should  be  the  winds  which,  in  the  general  course  of  circula- 
tion, would  be  carried,  after  crossing  the  Andes  and  rising  up  in 
the  belt  of  equatorial  calms,  toward  Northern  Africa,  Spain,  and 
the  South  of  Europe. 

391.  They  might  carry  with  them  the  infusoria  of  Ehrenberg 
(§  273),  but,  according  to  this  theory,  they  would  be  wanting  in 
moisture.  Now,  are  not  those  portions  of  the  Old  World,  for  the 
most  part  dry  countries,  receiving  but  a  small  amount  of  precipi- 
tation ? 

392.  Hence  the  general  rule :  those  countries  to  the  north  of 
the  calms  of  Cancer,  which  have  large  bodies  of  land  situated  to 
the  southward  and  westward  of  them,  in  the  southeast  trade- wind 
region  of  the  earth,  should  have  a  scanty  supply  of  rain,  and  vice 
versa, 

393.  Let  us  try  this  rule  :  The  extra-tropical  part  of  New  Hol- 
land comprises  a  portion  of  land  thus  situated  in  the  southern  hem- 
isphere. Tropical  India  is  to  the  northward  and  westward  of  it ; 
and  tropical  India  is  in  the  northeast  trade-wind  region,  and  should 
give  extra-tropical  New  Ilollard  a  slender  supply  of  rain.  But 
what  modifications  the  monsoons  of  the  Indian  Ocean  may  make 
to  this  rule,  or  what  effect  they  may  have  upon  the  rains  in  New 
HoUand,  ray  investigations  in  that  part  of  the  ocean  have  not  been 
carried  far  enougli  for  final  decision ;  though  New  Holland  is  a  dry 
country.  Eeferring  back  to  p.  84  for  what  has  been  already  said 
concerning  the  "Meteorological  Agencies"  (§  159)  of  the  at- 
mosphere, it  will  be  observed  that  cases  are  there  brought  forward 
which  afford  trials  for  this  rul^,  every  one  of  which  holds  good. 


MAGNETISM  AND  CIRCULATION  OF  THE  ATMOSPHERE.      I47 

394.  Thus,  tliougli  it  be  not  proved  as  a  matliematical  truth 
that  magnetism  is  the  power  which  guides  the  storm  from  right 
to  left  and  from  left  to  right,  which  conducts  the  moist  and  the 
dry  air  each  in  its  appointed  paths,  and  which  regulates  the  "wind 
in  his  circuits,"  yet  that  it  is  such  a  power  is  rendered  very  jDrob- 
able ;  for,  under  the  supposition  that  there  is  such  a  crossing  of 
the  air  at  the  five  calm  places,  as  Plate,  p.  75,  represents,  we  can 
reconcile  a  greater  number  of  known  facts  and  phenomena  than 
we  can  under  the  supposition  that  there  is  no  such  crossing.  The 
rules  of  scientific  investigation  always  require  us,  when  we  enter 
the  domains  of  conjecture,  to  adopt  that  hypothesis  by  which  the 
greatest  number  of  known  facts  and  phenomena  maybe  reconciled; 
and  therefore  we  are  entitled  to  assume  that  this  crossing  proba- 
bly does  take  place,  and  to  hold  fast  to  the  theory  so  maintaining 
until  it  is  shown  not  to  be  sound.* 

395.  That  the  magnetism  of  the  atmosphere  is  the  agent  which 
guides  the  air  across  the  calm  belts,  and  prevents  that  which  en- 
ters them  from  escaping  on  the  side  upon  which  it  entered,  we 
can  not,  of  our  own  knowledge,  positively  affirm.  Suffice  it  to 
say,  that  we  recognize  in  this  property  of  the  oxygen  of  air  an 
agent  that,  for  aught  we  as  yet  know  to  the  contrary,  may  serve 
as  such  a  guide  ;  and  we  do  not  know  of  the  existence  of  any  oth- 
er agent  in  the  atmosphere  that  can  perform  the  offices  which  the 
hypothesis  requires.  Hence  the  suspicion  that  magnetism  and 
electricity  are  among  the  forces  concerned  in  the  circulation  of  the 
atmosphere. 

*  See  Addenda. 

K 


148  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  VII. 

CUEEENTS    OF    THE    SEA. 

Governed  by  Laws,  ^  396. — The  Capacity  of  Water  to  convey  Heat,  399. — The  Red 
Sea  Current,  404. — The  per  centum  of  Salt  in  Sea  Water,  418. — The  Mediterra- 
nean Current,  423. — Under  Current  from,  424. — Admiral  Smyth's  Soundings,  426. — 
Lyell's  Views,  429. — Admiral  Smyth's  Views,  436. — Currents  of  the  Indian  Ocean, 
439. — Gulf  Stream  of  the  Pacific,  441. — Its  resemblance  to  that  of  the  Atlantic, 
442. — An  ice-bearing  Current  between  Africa  and  Australia,  449. — Currents  of  the 
Pacific,  451. — A  Sargossa  Sea  in  the  Pacific,  452. — Drift-wood  upon  the  Aleutian 
Islands,  453. — Cold  Ochotsk,  454. — Humboldt's  Current,  455. — Warm  Current  in 
the  South  Pacific,  456. — Equatorial  Currents  in  the  South  Pacific,  458. — The  Effect 
of  Rain  and  Evaporation  upon  Currents,  459. — Under  Currents  of  the  Atlantic,  461. 
— Equilibrium  of  the  Sea  maintained  by  Currents,  467. — The  Brazil  Current,  469. 

396.  Let  us,  in  this  chapter,  set  out  with  the  postulate  that  the 
sea,  as  well  as  the  air,  has  its  system  of  circulation,  and  that  this 
system,  whatever  it  be,  and  wherever  its  channels  lie,  whether  in 
the  waters  at  or  below  the  surface,  is  in  obedience  to  physical  laws. 
The  sea,  by  the  circulation  of  its  waters,  doubtless  has  its  offices 
to  perform  in  the  terrestrial  economy ;  and  when  we  see  the  cur- 
rents in  the  ocean  running  hither  and  thither,  we  feel  that  they 
were  not  put  in  motion  without  a  cause.  On  the  contrary,  reason 
assures  us  that  they  move  in  obedience  to  some  law  of  Nature,  be 
it  recorded  down  in  the  depths  below,  never  so  far  beyond  the 
reach  of  human  ken ;  and  being  a  law  of  Nature,  we  know  who 
gave  it,  and  that  neither  chance  nor  accident  had  any  thing  to  do 
with  its  enactment. 

397.  Nature  grants  us  all  that  this  postulate  demands,  repeat- 
ing it  to  us  in  many  forms  of  expression  ;  she  utters  it  in  the  blade 
of  green  grass  which  she  causes  to  grow  in  climates  and  soils  made 
kind  and  genial  by  warmth  and  moisture  that  some  current  of  the 
sea  or  air  has  conveyed  far  away  from  under  a  tropical  sun.  She 
murmurs  it  out  in  the  cooling  current  of  the  north  ;  the  whales  of 
the  sea  tell  of  it  (§  70),  and  all  its  inhabitants  proclaim  it.' 


CURRENTS  OF  THE  SEA.  149 

398.  The  fauna  and  the  flora  of  the  sea  are  as  much  the  crea- 
tures of  climate  (§  76),  and  are  as  dependent  for  their  well-being 
upon  temperature  as  are  the  fauna  and  the  flora  of  the  dry  land. 
Were  it  not  so,  we  should  find  the  fish  and  the  alga?,  the  marine 
insect  and  the  coral,  distributed  equally  and  alike  in  all  parts  of 
the  ocean.  The  polar  whale  would  delight  in  the  torrid  zone,  and 
the  habitat  of  the  pearl  oyster  would  be  also  under  the  iceberg,  or 
in  frigid  waters  colder  than  the  melting  ice. 

399.  Now  water,  while  its  capacities  for  heat  are  scarcely  ex- 
ceeded by  those  of  any  other  substance,  is  one  of  the  most  com- 
plete of  non-conductors.  Heat  does  not  permeate  water  as  it  does 
iron,  for  instance,  or  other  good  conductors.  Heat  the  top  of  an 
iron  plate,  and  the  bottom  becomes  warm  ;  but  heat  the  top  of  a 
sheet  of  water,  as  in  a  pool  or  basin,  and  that  at  the  bottom  re- 
mains cool.  The  heat  passes  through  iron  by  conduction,  but  to 
get  through  water  it  requires  to  be  conveyed  by  a  motion,  which 
in  fluids  we  call  currents. 

400.  Therefore  the  study  of  the  climates  of  the  sea  involves  a  • 
knowledge  of  its  currents,  both  cold  and  warm.     They  are  the 
channels  through  which  the  waters  circulate,  and  by  means  of 
which  the  harmonies  of  old  ocean  are  preserved. 

401.  Hence,  in  studying  the  system  of  oceanic  circulation,  we 
set  out  with  the  very  simple  assumption,  viz.,  that  from  whatever 
part  of  the  ocean  a  current  is  found  to  run,  to  the  same  part  a 
current  of  equal  volume  is  bound  to  return ;  for  upon  this  princi- 
ple is  based  the  whole  system  of  currents  and  counter-currents  of 
the  air  as  well  as  of  the  water. 

402.  Currents  of  water,  like  currents  of  air,  meeting  from  vari- 
ous directions,  create  gyrations,  which  in  some  parts  of  the  sea, 
as  on  the  coast  of  Norway,  assume  the  appearance  of  whirlpools, 
as  though  the  water  were  drawn  into  a  chasm  below.  The  cele- 
brated Maelstrom  is  caused  by  such  a  conflict  of  tidal  or  other 
streams.  Admiral  Beechey,  R.N.,*  has  given  diagrams  illustrative 
of  many  "rotatory  streams  in  the  English  Channel,  a  number  of 
which  occur  between  the  outer  extremities  of  the  channel  tide  and 

*  See  an  interesting  paper  by  him  on  Tidal  Streams  of  thxc  North  Sea  and  English 
Channel,  pp.  703  ;  Phil.  Transactions,  Part  ii.,  1851. 


150       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

the  stream  of  the  oceanic  or  parent  wave."  "  They  are  clearly  to 
be  accounted  for,"  says  lie,  "  by  the  streams  actmg  obliquely  upon 
each  other." 

403.  It  is  not  necessary  to  associate  with  oceanic  currents  the 
idea  that  they  must  of  necessity,  as  on  land,  run  from  a  higher  to 
a  lower  level.  So  far  from  this  being  the  case,  some  currents  of 
the  sea  actually  run  up  hill,  while  others  run  on  a  level. 

The  Gulf  Stream  is  of  the  first  class  (§9). 

404.  The  currents  which  run  from  the  Atlantic  into  the  Medi- 
terranean, and  from  the  Indian  Ocean  into  the  Red  Sea,  are  the 
reverse  of  this.  Here  the  bottom  of  the  current  is  probably  a  wa- 
ter-level, and  the  top  an  inclined  plane,  running  down  hill.  Take 
the  Hed  Sea  current  as  an  illustration.  That  sea  lies,  for  the 
most  part,  within  a  rainless  and  riverleSs  district.  It  may  be 
compared  to  a  long  and  narrow  trough.  Being  in  a  rainless  dis- 
trict, the  evaporation  from  it  is  immense ;  none  of  the  water  thus 
taken  up  is  returned  to  it  either  by  rivers  or  rains.  It  is  about 
one  thousand  miles  long ;  it  lies  nearly  north  and  south,  and  ex- 
tends from  latitude  13°  to  the  parallel  of  30°  north. 

405.  From  May  to  October,  the  water  in  the  upper  part  of  this 
sea  is  said  to  be  two  feet  lower  than  it  is  near  the  mouth. ^  This 
change  or  diiierence  of  level  is  ascribed  to  the  effect  of  the  wind, 
which,  prevailing  from  the  north  at  that  season,  is  supposed  to 
blow  the  water  out. 

406.  But  from  May  to  October  is  also  the  hot  season ;  it  is  the 
season  when  evaporation  is  going  on  most  rapidly ;  and  when  we 
consider  how  dry  and  how  hot  the  winds  are  which  blow  upon  this 
sea  at  this  season  of  the  year,  we  may  suppose  the  daily  evapora- 
tion to  be  immense;  not  less,  certainly,  than  half  an  inch,  and 
probably  twice  that  amount.  "We  know  that  the  waste  from  ca- 
nals by  evaporation,  in  the  summer  time,  is  an  element  which  the 
engineer,  when  taking  the  capacity  of  his  feeders  into  calculation, 
has  to  consider.  With  him  it  is  an  important  element ;  how  much 
more  so  must  the  waste  by  evaporation  from  this  sea  be,  when  we 
consider  the  physical  conditions  under  which  it  is  placed.  Its 
feeder,  the  Arabian  Sea,  is  a  thousand  miles  from  its  head ;  its 

*  Johnston's  Physical  Atlas. 


CURRENTS  OF  THE  SEA.  151 

shores  are  "burning  sands  ;  the  evaporation  is  ceaseless  /  and  none 
of  the  vapors,  which  the  scorching  winds  that  blow  over  it  cany 
away,  are  returned  to  it  again  in  the  shape  of  rains. 

407.  The  Red  Sea  vapors  are  carried  off  and  precipitated  else- 
where. The  depression  in  the  level  of  its  head  Avaters  in  the 
summer  time,  therefore,  it  appears,  is  owing  to  the  effect  of  evap- 
oration as  well  as  to  that  of  the  wind  blowing  the  waters  back. 

408.  The  evaporation  in  certain  parts  of  the  Indian  Ocean 
(§  33)  is  from  three  fourths  of  an  inch  to  an  inch  daily.  Suppose 
it  for  the  Red  Sea  in  the  summer  time  to  average  only  half  an 
inch  a  day. 

409.  Now,  if  we  suppose  the  velocity  of  the  current  which  runs 
into  that  sea  to  average,  from  mouth  to  head,  twenty  miles  a  day, 
it  would  take  the  water  fifty  days  to  reach  the  head  of  it.  If  it 
lose  half  an  inch  from  its  surface  by  evaporation  daily,  it  would, 
by  the  time  it  reaches  the  Isthmus  of  Suez,  lose  twenty-five  inches 
from  its  surface. 

410.  Thus  the  waters  of  the  Red  Sea  ought  to  be  lower  at 
the  Isthmus  of  Suez  than  they  are  at  the  Straits  of  Babelman- 
deb.  Independently  of  the  waters  forced  out  by  the  wind,  they 
ought  to  be  lower  from  two  other  causes,  viz.,  evaporation  and 
temperature,  for  the  temperature  of  that  sea  is  necessarily  lower 
at  Suez,  in  latitude  30°,  than  it  is  at  Babelniandeb,  in  latitude  13^. 

411.  To  make  it  quite  clear  that  the  surface  of  the  Red  Sea  is 
not  a  sea  level,  but  is  an  inclined  plane,  suppose  the  channel  of 
the  Red  Sea  to  have  a  perfectly  smooth  and  level  floor,  with  no 
water  in  it,  and  a  wave  ten  feet  high  to  enter  the  Straits  of  Babel- 
mandeb,  and  to  flow  up  the  channel  at  the  rate  of  twenty  miles  a 
day  for  fifty  days,  losing  daily,  by  evaporation,  half  an  inch ;  it  is 
easy  to  perceive  that,  at  the  end  of  the  fiftieth  day,  this  wave 
Avould  not  be  so  high,  by  two  feet  (twenty-five  inches),  as  it  was 
the  first  day  it  commenced  to  flow. 

412.  The  top  of  that  sea,  therefore,  may  be  regarded  as  an  in- 
clined plane,  made  so  by  evaporation. 

413.  But  the  salt  water,  which  has  lost  so  much  of  its  freshness 
by  evaporation,  becomes  Salter,  and  therefore  heavier.  The  light- 
er water  at  the  Straits  can  not  balance  the  heavier  water  at  the 


152  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

Isthmus,  and  the  colder  and  Salter,  and  therefore  heavier  water, 
must  either  run  out  as  an  under  current,  or  it  must  deposit  its  sur- 
plus salt  in  the  shape  of  crystals,  and  thus  gradually  make  the 
bottom  of  the  Eed  Sea  a  salt-bed,  or  it  must  abstract  all  the  salt 
from  the  ocean  to  make  the  Eed  Sea  brine — and  we  know  that 
neither  the  one  process  nor  the  other  is  going  on.  Hence  we  in- 
fer that  there  is  from  the  Ked  Sea  an  under  or  outer  current,  as 
there  is  from  the  Mediterranean  through  the  Straits  of  Gibraltar, 
and  that  the  surface  waters  near  Suez  are  Salter  than  those  near 
the  mouth  of  the  Eed  Sea. 

414.  And,  to  show  why  there  should  be  an  outer  and  under 
current  from  each  of  these  two  seas,  let  us  suppose  the  case  of  a. 
long  trough,  opening  into  a  vat  of  oil,  with  a  partition  to  keep  the 
oil  from  running  into  the  trough.  Now  suppose  the  trough  to  be 
iilled  up  with  wine  on  one  side  of  the  partition  to  the  level  of  the 
oil  on  the  other.  The  oil  is  introduced  to  represent  the  lighter 
water  as  it  enters  either  of  these  seas  from  the  ocean,  and  the  wine 
the  same  water  after  it  has  lost  some  of  its  freshness  by  evapora- 
tion, and  tlierefore  has  become  Salter  and  heavier,  Now  suppose 
the  partition  to  be  raised,  what  would  take  place  ?  Why,  the  oil 
would  run  in  as  an  upper  current,  overflowing  the  wine,  and  the 
wine  would  run  out  as  an  under  current. 

415.  The  rivers  which  discharge  in  the  Mediterranean  are  not 
sufficient  to  supply  the  waste  of  evaporation,  and  it  is  by  a  pro- 
cess similar  to  this  that  the  salt  which  is  carried  in  from  the  ocean 
is  returned  to  the  ocean  again  ;  were  it  not  so,  the  bed  of  that  sea 
would  be  a  mass  of  solid  salt.  The  equilibrium  of  the  seas  is 
preserved,  beyond  a  doubt,  by  a  system  of  compensation  as  exqui- 
sitely adjusted  as  are  those  by  which  the  "music  of  the  spheres" 
is  maintained. 

416.  It  is  difficult  to  form  an  adequate  conception  of  the  im- 
mense quantities  of  solid  matter,  in  solution,  which  the  current  from 
tlie  Atlantic  carries  into  the  Mediterranean.  In  the  abstract  log 
for  jMarch  8th,  1855,  Mr.  William  Grenville  Temple,  master  of 
the  United  States  ship  Levant,  homeward  bound,  has  described 
the  indrauo'ht  there : 

"•  Weather  fine  ;  made  1^  pt.  lee-way.    At  noon,  stood  in  to  Al- 


CURRENTS  OF  THE  SEA.  X53 

miria  Bay,  and  anchored  off  the  village  of  Roguetas.  Found  a 
great  number  of  vessels  waiting  for  a  chance  to  get  to  the  west- 
ward, and  learned  from  them  that  at  least  a  thousand  sail  are 
weather-bound  between  this  and  Gibraltar.  Some  of  them  have 
been  so  for  six  weeks,  and  have  even  got  as  far  as  Malaga,  only 
to  be  swept  back  by  the  cuiTcnt.  Indeed,  no  vessel  has  been  able 
to  get  out  into  the  Atlantic  for  three  months  past." 

417.  Now,  suppose  this  current,  which  baffled  and  beat  back 
this  fleet  for  so  many  days,  ran  no  faster  than  two  knots  the  hour. 
Assuming  its  depth  to  be  400  feet  only,  and  its  width  seven  miles, 
and  that  it  carried  in  with  it  the  average  proportion  of  solid  matter 
— say  one  thirtieth — contained  in  sea  water ;  and  admitting  these 
postulates  into  calculation  as  the  basis  of  the  computation,  it  ap- 
pears that  salts  enough  to  make  no  less  than  88  cubic  miles  of 
solid  matter,  of  the  density  of  water,  were  carried  into  the  Medi- 
terranean during  these  90  days.  Now,  unless  there  were  some  es- 
cape for  all  this  solid  matter,  which  has  been  running  into  that 
sea,  not  for  90  days  merely,  but  for  ages,  it  is  very  clear  that  the 
Mediterranean  would,  ere  this,  have  been  a  vat  of  very  strong 
brine,  or  a  bed  of  cubic  crystals. 

418.  Let  us  see  the  results  of  actual  observation  upon  the  den- 
sity of  water  in  the  Red  Sea  and  the  Mediterranean,  and  upon  the 
under  currents  that  run  out  from  these  seas. 

419.  Four  or  five  years  ago,  ]\[r.  JMorris,  chief  engineer  of  the 
Oriental  Company's  steam-ship  Ajdaha,  collected  specimens  of  Red 
Sea  water  all  the  way  from  Suez  to  the  Straits  of  Babelmandeb, 
which  were  afterward  examined  by  Dr.  Giraud,  who  reported  the 
following  results  :* 


Latitude. 

Longitude. 

Spec,  Grav, 

Saline  Cont, 

No. 

1. 

Sea  at  Suez 

0 

o 

1027 

1000  parts. 

41.0 

No. 

2. 

Gulf  of  Suez 

27.49 

33.44 

1026 

40.0 

No. 

3. 

Red  Sea 

24.29 

36. 

1024 

39.2 

No. 

4. 

do. 

20.55 

38.18 

1026 

40.5 

No. 

5. 

do. 

20.43 

40.03 

1024 

39.8 

No. 

6. 

do. 

14.34 

42.43 

1024 

39.9 

No. 

7. 

do. 

12.39 

44.45 

1023 

39.2 

420.  These  observations  as-ree  with  the  theoretical  deductions 

o 
*  Transact,  of  the  Bombay  Geograph.  Soc.,  vol.  ix.,  May,  1849,  to  August,  1850. 


154  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

just  announced,  and  show  that  the  surface  waters  at  the  head  are 
heavier  and  Salter  than  the  surface  waters  at  the  mouth  of  the 

Eed  Sea. 

421.  In  the  same  paper,  the  temperature  of  the  air  between 
Suez  and  Aden  often  rises,  it  is  said,  to  90°,  "  and  probably  aver- 
ao-es  little  less  than  75°  day  and  night  all  the  year  round.     The 
surface  of  this  sea  varies  in  heat  from  65°  to  85°,  and  the  differ- 
ence between  the  wet  and  dry  bulb  thermometers  often  amounts 
to  25° — in  tlie  kamsin,  or  desert  winds,  to  from  30°  to  40°  ;  the 
average  evaporation  at  Aden  is  about  eight  feet  for  the  year." 
"Now  assuming,"  says  Dr.  Buist,  "the  evaporation  of  the  Eed 
Sea  to  be  no  greater  than  that  of  Aden,  a  sheet  of  water  eight  feet 
thick,  equal  in  area  to  the  whole  expanse  of  that  sea,  will  be  car- 
ried off  annually  in  vapor  ;  or,  assuming  the  Eed  Sea  to  be  eight 
hundred  feet  in  depth  at  an  average — and  this,  most  assuredly,  is 
more  than  double  the  fact — the  whole  of  it  would  be  dried  up, 
w^ere  no  w^ater  to  enter  from  the   ocean,  in  one  hundred  years. 
The  waters  of  the  Eed  Sea,  throughout,  contain  gome  four  per 
cent,  of  salt  by  weight — or,  as  salt  is  a  half  heavier  than  water, 
some  2.7  per  cent,  in  bulk — or,  in  round  numbers,  say  three  per 
cent.     In  the  course  of  three  thousand  years,  on  the  assumptions 
just  made,  the  Red  Sea  ought  to  have  been  one  mass  of  solid  salt, 
if  there  were  no  current  running  out." 

422.  Now  we  know  the  Eed  Sea  is  more  than  three  thousand 
years  old,  and  that  it  is  not  filled  with  salt ;  and  the  reason  is, 
that  as  fast  as  the  upper  currents  bring  the  salt  in  at  the  top,  the 
under  currents  carry  it  out  at  the  bottom. 

423.  Mediterranean  Cueeents. — With  regard  to  an  under 
current  from  the  Mediterranean,  we  may  begin  by  remarking  that 
we  know  that  there  is  a  current  always  setting  in  at  the  surface 
from  the  Atlantic,  and  that  this  is  a  salt-water  current,  which  car- 
ries an  immense  amount  of  salt  into  that  sea.  We  know,  more- 
over, that  that  sea  is  not  salting  up ;  and  therefore,  independently 
of  the  postulate  (§  401)  and  of  observations,  we  might  infer  the 
existence  of  an  under  current,  through  which  this  salt  finds  its 
way  out  into  the  broad  ocean  again.* 

*  Dr.  Smith  appears  to  have  been  the  first  to  conjecture  this  explanation,  which  he 


CURRENTS  OF  THE  SEA.  I55 

Witli  regard  to  this  outer  and  under  current,  we  have  observa- 
tions telling  of  its  existence  as  long  ago  as  1712. 

424.  "In  the  year  1712,"  says  Dr.  Hudson,  in  a  paper  com- 
municated to  the  Philosophical  Society  in  1724,  "Monsieur  du 
L'Aigle,  that  fortunate  and  generous  commander  of  the  privateer 
called  the  Phoenix,  of  Marseilles,  giving  chase  near  Ceuta  Point 
to  a  Dutch  ship  bound  to  Holland,  came  up  with  her  in  the  mid- 
dle of  the  Gut  between  Tariffa  and  Tangier,  and  there  gave  her 
one  broadside,  which  directly  sunk  her,  all  her  men  being  saved 
by  Monsieur  du  L'Aigle ;  and  a  few  days  after,  the  Dutch  ship, 
with  her  cargo  of  brandy  and  oil,  arose  on  the  shore  near  Tangier, 
which  is  at  least  four  leagues  to  the  westward  of  the  place  where 
she  sunk,  and  directly  against  the  strength  of  the  current,  which 
has  persuaded  many  men  that  there  is  a  recurrency  in  the  deep 
water  in  the  middle  of  the  Gut  that  sets  outward  to  the  grand 
ocean,  which  this  accident  very  much  demonstrates;  and,  possi- 
bly, a  great  part  of  the  water  which  runs  into  the  Straits  returns 
that  way,  and  along  the  two  coasts  before  mentioned ;  otherwise, 
this  ship  must,  of  course,  have  been  driven  toward  Ceuta,  and  so 
upward.  The  water  in  the  Gut  must  be  very  deep ;  several  of 
the  commanders  of  our  ships  of  war  having  attempted  to  sound  it 
with  the  longest  lines  they  could  contrive,  but  could  never  find 
any  bottom." 

did  in  1683  (vide  Philosophical  Transactions).  This  continual  indraught  into  the 
Mediterranean  appears  to  have  been  a  vexed  question  among  the  navigators  and  phi- 
losophers even  of  those  times.  Dr.  Smith  alludes  to  several  hypotheses  which  had 
been  invented  to  solve  these  phenomena,  such  as  subterraneous  vents,  cavities,  exha- 
lation by  the  sun's  beams,  etc.,  and  then  offers  his  conjecture,  which,  in  his  own 
words,  is,  "that  there  is  an  under  current,  by  which  as  great  a  quantity  of  water  is 
carried  out  as  comes  flowing  in.  To  confirm  which,  besides  what  I  have  said  above 
about  the  difference  of  tides  in  the  offing^and  at  the  shore  in  the  Downs,  which  nec- 
essarily supposes  an  under  current,  I  shall  present  you  with  an  instance  of  the  lik^ 
nature  in  the  Baltic  Sound,  as  I  received  it  from  an  able  seaman,  who  was  at  the 
making  of  the  trial.  He  told  me  that,  being  there  in  one  of  the  king's  frigates,  thev 
went  with  their  pinnace  into  the  mid  stream,  and  were  carried  violently  by  the  cur- 
rent ;  that,  soon  after  this,  they  sunk  a  bucket  with  a  heavy  cannon  ball  to  a  certain 
depth  of  water,  which  gave  a  check  to  the  boat's  motion ;  and,  sinking  it  still  lower 
and  lower,  the  boat  was  driven  ahead  to  the  windward  against  the  upper  current : 
the  current  aloft,  as  he  added,  not  being  over  four  or  five  fathoms  deep,  and  that  the 
lower  the  bucket  was  let  fall,  they  found  the  under  current  the  stronger." 


156  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

425.  In  1828,  Dr.  Wollaston,  in  a  paper  before  the  Philosopli' 
ical  Society,  stated  that  he  found  the  specific  gravity  of  a  specimen 
of  sea  water,  from  a  depth  of  six  hundred  and  seventy  fathoms, 
fifty  miles  within  the  Straits,  to  have  a  "density  exceeding  that 
of  distilled  water  by  more  than  four  -times  the  usual  excess,  and 
accordingly  leaves,  upon  evaporation,  more  than  four  times  the 
usual  quantity  of  saline  residuum.  Hence  it  is  clear  that  an  un- 
der current  outward  of  such  denser  water,  if  of  equal  breadth  and 
depth  with  the  current  inward  near  the  surface,  would  carry  out 
as  much  salt  below  as  is  brought  in  above,  although  it  moved 
with  less  than  one  fourth  part  of  the  velocity,  and  would  thus  pre- 
vent a  perpetual  increase  of  saltness  in  the  Mediterranean  Sea 
beyond  that  existing  in  the  Atlantic." 

426.  The  doctor  obtained  this  specimen  of  sea  water  from  Cap- 
tain, now  Admiral  Smyth,  of  the  English  Navy,  who  had  collected 
it  for, Dr.  Marcet.  Dr.  Marcet  died  before  receiving  it,  and  it  had 
remained  in  the  admiral's  hands  some  time  before  it  came  into 
those  of  Wollaston. 

427.  It  may,  therefore,  have  lost  something  by  evaporation; 
for  it  is  difficult  to  conceive  that  all  the  river  water,  and  three 
fourths  of  the  sea  water  which  runs  into  the  Mediterranean,  is 
evaporated  from  it,  leaving  a  brine  for  the  under  current  having 
four  times  as  much  salt  as  the  water  at  the  surface  of  the  sea 
usually  contains.  Very  recently,  M.  Coupvent  des  Bois  is  said 
to  have  shown,  by  actual  observation,  the  existence  of  an  outer 
and  under  current  from  the  Mediterranean. 

428.  However  that  may  be,  these  facts,  and  the  statements  of  the 
Secretary  of  the  Geographical  Society  of  Bombay  (§  421),  seem  to 
leave  no  room  to'  doubt  as  to  the  existence  of  an  under  current 
both  from  the  Red  Sea  and  ]\Iediterranean,  and  as  to  the  cause  of 
the  surfoce  current  which  flows  into  them.  I  think  it  a  matter  of 
demonstration.     It  is  accounted  for  (§  413)  by  the  salts  of  the  sea. 

429.  Writers  whose  opinions  are  entitled  to  great  respect  differ 
with  me  as  to  the  conclusiveness  of  this  demonstration.  Among 
these  writers  are  Admiral  Smyth,  of  the  British  Navy,  and  Sir 
Charles  Lyell,  who  also  differ  with  each  other.  In  1820,  Dr.  Mar- 
cet, being  then  engaged  in  studying  the  chemical  composition  of 


CURRENTS  OF  THE  SEA.  I57 

sea  water,  the  admiral,  with  his  usual  alacrity  for  doing  "a  kind 
turn,"  undertook  to  collect  for  the  doctor  specimens  of  Mediterra- 
nean water  from  various  depths,  especially  in  and  about  the  Straits 
of  Gibraltar.  Among  these  was  the  one  (§  425)  taken  fifty  miles 
within  the  Straits  from  the  depth  of  six  hundred  and  seventy 
fathoms  (four  thousand  and  twenty  feet),  which,  being  four  times 
Salter  than  common  sea  water,  left,  as  we  have  just  seen  (§  425), 
no  doubt  in  the  mind  of  Dr.  Wollaston  as  to  the  existence  of  this 
under  current  of  brine. 

430.  But  the  indefatigable  admiral,  in  the  course  of  his  cele- 
brated survey  of  the  Mediterranean,  discovered  that,  while  inside 
of  the  Straits  the  depih  was  upward  of  nine  hundred  fiithoms,  yet 
in  the  Straits  themselves  the  depth  across  the  shoalest  section  is 
not  more  than  one  hundred  and  sixty*  fathoms. 

"Such being  the  case,  we  can  now  prove,"  exclaims  Sh  Charles 
Lyell,  "  that  the  vast  amount  of  salt  brought  into  tlie  Mediterra- 
nean does  not  pass  out  again  by  the  Straits ;  for  it  appears  by 
Captain  Smyth's  soundings,  which  Dr.  Wollaston  had  not  seen, 
that  between  the  Gapes  of  Trafalgar  and  Spartel,  wliicli  are  twenty- 
two  miles  apart,  and  Avhere  the  Straits  are  shallowest,  the  deep- 
est part,  which  is  on  the  side  of  Cape. Spartel,  is  only  two  hundred 
and  twenty  fathoms.!  It  is  therefore  evident,  that  if  water  sinks 
in  certain  parts  of  the  Mediterranean,  in  consequence  of  the  in- 
crease of  its  specific  gravity,  to  greater  depths  than  two  hundred 
and  twenty  fathoms,  it  can  never  flow  out  again  into  the  Atlantic, 
since  it  must  be  stopped  by  the  submarine  barrier  which  crosses 
the  shallowest  part  of  the  Straits  of  Gibraltar,  "f 

431.  According  to  this  reasoning,  all  the  cavities,  the  hollows 
and  the  valleys  at  the  bottom  of  the  sea,  especially  in  the  trade- 
wind  region,  where  evaporation  is  so  constant  and  great,  ought  to 
be  salting  up  or  filling  up  with  brine.  Is  it  probable  that  such  a 
process  is  actually  going  on  ?     No. 

432.  According  to  this  reasoning,  the  water  at  the  bottom  of 
the  great  American  lakes  ought  to  be  salt,  for  the  rivers  and  the 
rains,  it  is  admitted,  bring  salts  from  tlie  land  continually  and 


■X-     <<  ' 


The  Mediterranean."  t  One  hundred  and  sixty,  Smyth. 

X  Lyell's  Principles  of  Geology,  p.  334-5,  ninth  edition.     London,  1853. 


158  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

empty  tliem  into  the  sea.  It  is  also  admitted  that  the  great  lakes 
would,  from  this  cause,  be  salt,  if  they  had  no  sea  drainage.  The 
Niagara  River  passes  these  river  salts  from  the  upper  lakes  into 
Ontario,  and  the  St.  Lawrence  conveys  them  thence  to  the  sea. 
Now  the  basins  or  bottoms  of  all  these  upper  lakes  are  far  below 
the  to])  of  the  rock  over  which  the  Niagara  pitches  its  flood.  And, 
were  the  position  assumed  by  this  writer  correct,  viz.,  that  if  the 
water  in  any  of  these  lakes  should,  in  consequence  of  its  specific 
gravity,  once  sink  below  the  level  of  the  shoals  in  the  rivers  and 
straits  which  connect  them,  it  never  could  flow  out  again,  and 
consequently  must  remain  there  forever* — were  this  principle 
physically  correct,  would  not  the  water  at  the  bottom  of  the  lakes 
gradually  have  received  salt  sufficient,  during  the  countless  ages 
that  they  have  been  sending  it  off  to  the  sea,  to  make  this  ever- 
lastingly pent-up  water  briny,  or  at  least  quite  diiferent  in  its  con- 
stituents from  that  of  the  surface  ?  We  may  presume  that  the 
water  at  the  bottom  of  every  extensive  and  quiet  sheet  of  water, 
whether  salt  or  fresh,  is  at  the  bottom  by  reason  of  specific  grav- 
ity ;  but  that  it  does  not  remain  there  forever  we  have  abundant 
proof.  If  so,  the  Niagara  River  would  be  fed  by  Lake  Erie  only 
from  that  layer  of  water  whicli  is  above  the  level  of  the  top  of  the 
rock  at  the  Falls.  Consequently,  wherever  the  breadth  of  that 
river  is  no  greater  than  it  is  at  the  Falls,  we  should  have  a  cur- 
rent as  rapid  as  it  is  at  the  moment  of  passing  the  top  of  the  rock 
to  make  the  leap.  To  see  that  such  is  not  the  way  of  Nature,  we 
have  but  to  look  at  any  common  mill-pond  when  the  water  is  run- 
ning over  the  dam.  The  current  in  the  pond  that  feeds  the  over- 
flow is  scarcely  perceptible,  for  "still  water  runs  deep."  More- 
over, we  know  it  is  not  such  a  skimming  current  as  the  geologist 
would  make,  which  runs  from  one  lake  to  another ;  for  wherever 
above  the  Niagara  Falls  the  water  is  deep,  there  we  are  sure  to 
find  the  current  sluggish,  in  comparison  with  the  rate  it  assumes, 
as  it  approaches  the  Falls  ;  and  it  is  sluggish  in  deep  places,  rapid 
in  shallow  ones,  because  it  is  fed  from  below.  The  common 
"  wastes"  in  our  canals  teach  us  this  fact. 

433.   The  reasoning  of  this  celebrated  geologist  appears  to  be 

*  See  paragraph  quoted  (^  430)  from  "  Lyell's  Principles  of  Geology." 


CURRENTS  OF  THE  SEA.  159 

founded  upon  the  assumption  tliat  when  water,  in  consequence  of 
its  specific  gravity,  once  sinks  below  the  bottom  of  a  current 
where  it  is  shallowest,  there  is  no  force  of  traction  in  fluids,  nor 
any  other  power,  which  can  draw  this  heavy  water  up  again.  If 
such  were  the  case,  we  could  not  have  deep  water  immediately  in- 
side of  the  bars  which  obstruct  the  passage  of  the  great  rivers  into 
the  sea.  Thus  the  bar  at  the  mouth  of  the  Mississippi,  with  only 
fifteen  feet  of  water  on  it,  is  estimated  to  travel  out  to  sea  at  rates 
varj^ing  from  one  hundred  to  twenty  yards  a  year. 

434.  In  the  place  where  that  bar  was  when  it  was  one  thousand 
yards  nearer  to  New  Orleans  than  it  now  is,  whether  it  were  fif- 
teen years  ago  or  a  century  ago,  with  only  fifteen  or  sixteen  feet 
of  water  on  it,  we  have  now  four  or  five  times  that  depth.  As 
new  bars  were  successively  formed  seaward  from  the  old,  what 
dug  up  the  sediment  which  formed  the  old,  and  lifted  it  up  from 
where  specific  gravity  had  placed  it,  and  carried  it  out  to  sea  over 
a  barrier  not  more  than  a  few  feet  from  the  surface?  Indeed, 
Sir  Charles  himself  makes  this  majestic  stream  to  tear  up  its 
own  bottom  to  depths  far  below  the  top  of  the  bar  at  its  mouth. 
He  describes  the  Mississippi  as  a  river  having  nearly  a  uniform 
breadth  to  the  distance  of  two  thousand  miles  froni  the  sea.*  He 
makes  it  cut  a  bed  for  itself  out  of  the  soil,  which  is  heavier  than 
Admiral  Smyth's  deep  sea  water,  to  the  depth  of  more  than  two 
hundred  feetf  below  the  top  of  the  bar  which  obstructs  its  en- 
trance into  the  sea.  Could  not  the  same  power  which  scoops  out 
this  solid  matter  for  the  Mississippi,  draw  the  brine  up  from  the 
pool  in  the  Mediterranean,  and  pass  it  out  across  the  barrier  in 
the  Straits  ? 

435.  The  traction  of  locomotives  on  rail-roads  and  the  force  of 
that  traction  is  well  understood.  Now  have  not  currents  in  the 
deep  sea  power  derived  from  sonie  such  force  ?  Suppose  this  un- 
der current  from  the  Mediterranean  to  extend  one  hundred  and 
sixty  fathoms  down,  so  as  to  chafe  the  barrier  across  the  Straits. 

*  "  From  near  its  mouth  at  the  Bahze,  a  steam-boat  may  ascend  for  two  thousand 
miles  with  scarcely  any  perceptible  difference  in  the  width  of  the  river." — LyelU  P-  263. 

t  "  The  Mississippi  is  continually  shifting  its  course  in  the  great  alluvial  plain,  cut- 
ting frequently  to  the  depth  of  one  hundred,  and  even  sometimes  to  the  depth  of  two 
hundred  and  fifty  feet:'— Lyell,  p.  273. 


160       THE  PHYSICAL  GEOGRAPHY  OF  THE*  SEA. 

Upon  the  bottom  of  this  current,  then,  there  is  a  pressure  of  more 
than  fifty  atmospheres.  Have  we  not  here  a  source  of  power  that 
would  be  capable  of  drawing  up,  by  almost  an  insensibly  slow 
motion,  water  from  almost  any  depth  ?  At  any  rate,  it  appears 
that  the  effect  of  currents  by  traction^^OY  friction,  or  whatever  force, 
does  extend  far  below  the  level  of  their  beds  in  shallow  places. 
Were  it  not  so — were  the  brine  not  drawn  out  again — it  would 
be  easy  to  prove  that  this  indraught  into  the  Mediterranean  has 
taken,  even  during  the  period  assigned  by  Sir  Charles  to  the  form- 
ation of  the  Delta  of  the  Mississippi — one  of  the  newest  forma- 
tions— salt  enough  to  fill  up  the  whole  basin  of  the  Mediterranean 
with  crystals.  Admiral  Smyth  brought  up  bottom  with  his  briny 
sample  of  deep  sea  water  (six  hundred  and  seventy  fathoms),  but 
no  salt  crystals. 

436.  The  gallant  admiral — appearing  to  withhold  his  assent 
both  from  Dr.  Wollaston  in  his  conclusions  as  to  this  under  cur- 
rent, and  from  the  geologist  in  his  inferences  as  to  tliQ  effect  of 
the  barrier  in  the  Straits — suggests  the  probability  that,  in  sound- 
ing for  the  heavy  specimen  of  sea  v/ater,  he  struck  a  brine  spring. 
But  the  specimen,  according  to  analysis,  was  of  sea  water,  and 
how  did  a  brine  spring  of  sea  water  get  under  the  sea  but  through 
the  process  of  evaporation  on  the  surface,  or  by  parting  with  a 
portion  of  its  fresh  water  in  some  other  way  ? 

437.  If  we  admit  the  principle  assumed  by  Sir  Charles  Lyell, 
that  water  from  the  great  pools  and  basins  of  the  sea  can  never 
ascend  to  cross  the  ridges  which  form  these  pools  and  basins,  then 
the  harmonies  of  the  sea  are  gone,  and  we  are  forced  to  conclude 
they  never  existed.  Every  particle  of  water  that  sinks  below  a 
submarine  ridge  is,  ipso  facto,  by  his  reasoning,  stricken  from  the 
channels  of  circulation,  to  become  thenceforward  forever  motion- 
less matter.  The  consequence  would  be  "cold  obstruction"  in 
the  depths  of  the  sea,  and  a  system  of  circulation  between  differ- 
ent seas  of  the  waters  only  that  float  above  the  shoalest  reefs  and 
barriers.  I  do  not  believe  in  the  existence  of  any  such  imperfect 
terrestrial  mechanism,  or  in  any  such  failures  of  design.  To  my 
mind,  the  proofs — the  theoretical  proofs — the  proofs  derived  ex- 
clusively from  reason  and  analogy — are  as  clear  in  favor  of  tliis 


CURRENTS  OF  THE  SEA,  161 

under  current  from  tlie  ^lediterranean  as  tliej  were  in  favor  of  tlie 
existence  of  Leverrier's  planet  before  it  was  seen  tlirougli  the  tele- 
scope at  Berlin. 

438.  Now  suppose,  as  Sir  Charles  Lyell  maintains,  tliat  none 
of  these  vast  quantities  of  salt  which  this  surface  current  takes 
into  the  ]\Iediterranean  find  their  way  out  again.  It  would  not 
be  difficult  to  show,  even  to  the  satisfaction  of  that  eminent  geol- 
ogist, that  tliis  indraught  conveys  salt  away  from  the  Atlantic 
faster  than  all  the  fiesk-watev  rivers  empty  fresh  supplies  of  salt 
into  the  ocean.  Now,  besides  this  drain,  vast  quantities  of  salts 
are  extracted  from  sea  water  for  madrepores,  coral  reefs,  shell 
banks,  and  marl  beds ;  and  by  such  reasoning  as  this,  which  is 
perfectly  sound  and  good,  we  establish  the  existence  of  this  under 
current,  or  else  we  are  forced  to  the  very  unphilosophical  conclu- 
sion that  the  sea  must  be  losing  its  salts,  and  becoming  less  and 
less  briny. 

439.  The  Cueeents  of  the  Indian  Ocean. — By  carefully 
examining  the  physical  features  of  this  sea  (Plates  VIII.  and  IX.), 
and  studying  its  conditions,  we  are  led  to  look  for  warm  currents 
that  have  their  genesis  in  this  ocean,  and  that  carry  from  it  vol- 
umes of  overlieated  water,  probably  exceeding  in  quantity  many 
times  that  which  is  discharged  by  the  Gulf  Stream  from  its  fount- 
ains (Plate  VI.). 

440.  The  Atlantic  Ocean  is  open  at  the  north,  but  tropical 
countries  bound  the  Indian  Ocean  in  that  direction.  The  waters 
of  this  ocean  are  hotter  than  those  of  the  Caribbean  Sea,  and  the 
evaporating  force  there  (§210)  is  much  greater.  That  it  is  greater 
we  might,  without  observation,  infer  from  the  fact  of  a  higher 
temperature  and  a  greater  amount  of  precipitation  on  the  neigh- 
boring shores  (§  202).  These  two  facts,  taken  together,  tend,  it 
would  seem,  to  show  that  large  currents  of  warm  water  have  their 
genesis  in  the  Indian  Ocean.  One  of  them  is  the  well-known 
Mozambique  current,  called  at  the  Cape  of  Good  Hope  the  La- 
gullas  current. 

441.  Another  of  these  currents  makes  its  escape  through  the 
Straits  of  Malacca,  and,  being  joined  by  other  warm  streams  from 
the  Java  and  China  Seas,  flows  out  into  the  Pacific,  like  another 


162  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

Gulf  Stream,  between  the  Philippines  and  the  shores  of  Asia. 
Thence  it  attempts  the  great  circle  route  (§  53)  for  the  Aleutian 
Islands,  tempering  climates,  and  losing  itself  in  the  sea  on  its 
route  toward  the  northwest  coast  of  America. 

442.  Between  the  physical  features  of  this  current  and  the 
Gulf  Stream  of  the  Atlantic  there  are  several  points  of  resem- 
blance. Sumatra  and  Malacca  correspond  to  Florida  and  Cuba ; 
Borneo  to  the  Bahamas,  with  the  Old  Providence  Channel  to  the 
south,  and  the  Florida  Pass  to  the  west.  The  coasts  of  China 
answer  to  those  of  the  United  States,  the  Philippines  to  the  Ber- 
mudas, the  Japan  Islands  to  Newfoundland.  As  with  the  Gulf 
Stream,  so  also  here  with  this  China  current,  there  is  a  counter- 
current  of  cold  water  between  it  and  the  shore.  The  climates  of 
the  Asiatic  coast  correspond  with  those  of  America  along  the  At- 
lantic, and  those  of  Columbia,  Washington,  and  Vancouver  are 
duplicates  of  those  of  Western  Europe  and  the  British  Islands  ; 
the  climate  of  California  (State)  resembling  that  of  Spain ;  the 
sandy  plains  and  rainless  regions  of  Lower  California  reminding 
one  of  Africa,  -with  its  deserts  between  the  same  parallels,  etc. 

443.  Moreover,  the  North  Pacific,  like  the  North  Atlantic,  is 
enveloped,  wdiere  these  warm  waters  go,  with  mists  and  fogs,  and 
streaked  with  lightiihig.  The  Aleutian  Islands  are  almost  as  re- 
nowned for  fogs  and  mists  as  are  the  Grand  Banks  of  Newfoundland. 

444.  A  surface  current  flows  north  through  Behring's  Strait 
into  the  Arctic  Sea ;  but  in  the  Atlantic  the  current  is  from,  not 
into  the  Arctic  Sea :  it  flows  south  on  the  surface,  north  below ; 
Behring's  Strait  being  too  shallow  to  admit  of  mighty  under  cur- 
rents, or  to  permit  the  introduction  from  the  polar  basin  of  any 
large  icebergs  into  the  Pacific. 

445.  Behring's  Strait,  in  geographical  position,  answers  to  Da- 
vis's Strait  in  the  Atlantic ;  and  Alaska,  with  its  Aleutian  chain 
of  islands,  to  Greenland.  But  instead  of  there  being  to  the  east 
of  Alaska,  as  there  is  to  the  east  of  Greenland,  an  escape  into  the 
polar  basin  for  these  warm  waters  of  the  Pacific,  a  shore-line  inter- 
venes, and  turns  them  down  through  a  sort  of  North  Sea  along 
the  western  coast  of  the  continent  toward  ]\Iexico.  They  appear 
here  as  a  cold  current.    The  effect  of  this  body  of  cool  water  upon 


CURRENTS  OF  THE  SEA.  Ig3 

the  littoral  climate  of  California  is  very  marked.  Being  cool,  it 
gives  freshness  and  strength  to  the  sea-breeze  of  that  coast  in 
summer  time,  when  the  "  cooling  sea-breeze"  is  most  grateful. 

446.  These  contrasts  show  the  principal  points  of  resemblance 
and  of  difference  between  the  currents  and  aqueous  circulation  in 
the  two  oceans.  The  ice-bearing  currents  of  the  North  Atlantic 
are  not  repeated  as  to  volum^e  in  the  North  Pacific,  for  there  is  no 
nursery  for  icebergs  like  the  frozen  ocean  and  its  arms.  The  seas 
of  Okotsk  and  Kamschatka  alone,  and  not  the  frozen  seas  of  the 
Arctic,  cradle  the  icebergs  for  the  North  Pacific. 

447.  There  is,  at  times  at  least,  another  current  of  warm  water 
from  the  Indian  Ocean.  It  finds  its  way  south  midway  between 
Africa  and  Australia,  and  appears  to  lose  itself  in  a  sort  of  Sar- 
gasso Sea,  thinly  strewed  with  patches  of  weed.  The  whales  also 
(Plate  IX.)  give  indications  of  it.  Nor  need  we  be  surprised  at 
such  a  vast  flow  of  warm  water  as  these  three  currents  indicate 
from  the  Indian  Ocean,  when  we  recollect  that  this  ocean  (§  439) 
is  land-locked  on  the  north,  and  that  the  temperature  of  its  waters 
is  frequently  as  high  as  90°  Fahr. 

448.  There  must,  therefore,  be  immense  volumes  of  water  flow- 
ing into  the  Indian  Ocean  to  supply  the  waste  created  by  these 
warm  currents,  and  the  fifteen  or  twenty  feet  of  water  that  obser- 
vations (§  33)  tell  us  are  yearly  carried  off  from  this  ocean  by 
evaporation. 

449.  On  either  side  of  this  warm  current  that  escapes  from  the 
inter-tropical  parts  of  the  Indian  Ocean  (§  447),  midway  between 
Africa  and  Australia,  an  ice-bearing  current  (Plate  IX.)  is  found 
wending  its  way  from  the  Antarctic  regions  with  supplies  of  cold 
water  to  modify  climates,  and  restore  the  aqueous  equilibrium  in 
that  part  of  the  world.  The  current  that  flows  up  to  the  west  of 
this  weedy  sea  is  the  greatest  ice-bearer.  Its  bergs  occasionally 
interfere  with  vessels  bound  to  Australia  by  the  new  route ;  those 
of  the  other  seldom.  The  former  sometimes  drifts  its  ice  as  far 
north  as  the  parallel  of  40°  south.  The  Gulf  Stream  seldom  per- 
mits them  to  get  so  near  the  equator  as  that  in  the  North  Atlan- 
tic, but  I  have  known  the  ice-bearing  current  which  passes  east 
of  Cape  Horn  into  the  South  Atlantic  to  convey  its  bergs  as  far 

L 


164  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

as  the  parallel  of  37°  south  latitude.    This  is  the  nearest  approach 
of  icebergs  to  the  equator. 

450.  These  currents  wliich  run  out  from  the  inter-tropical  basin 
of  that  immense  sea — Indian  Ocean^ — are  active  currents.  They 
convey  along  immense  volumes  of  water  containing  vast  quanti- 
ties of  salt,  and  we  know  that  sea  water  enough  to  convey  back 
equal  quantities  of  salt,  ai^id  salt  to  keep  up  supplies  for  the  out- 
going currents,  must  flow  into  or  return  to  the  inter-tropical  re- 
gions of  the  same  sea ;  therefore,  if  observations  were  silent  upon 
the  subject,  reason  would  teach  us  to  look  for  currents  here  that 
keep  in  motion  immense  volumes  of  water. 

451.  The  Cureents  of  the  Pacific. — The  contrast  has  been 
drawn  (§  442)  between  the  China  or  "  Gulf  Stream"  of  the  North 
Pacific,  and  the  Gulf  Stream  of  the  North  Atlantic.  The  course 
of  the  China  Stream  has  never  been  satisfactorily  traced  out. 
There  is  (Plate  IX.),  along  the  coast  of  California  and  Mexico,  a 
southwardly  movement  of  waters,  as  there  is  along  the  west  coast 
of  Africa  toward  the  Cape  de  Verd  Islands. 

452.  In  the  open  space  west  of  this  southwardly  set  along  the 
African  coast,  there  is  the  famous  Sargasso  Sea  (Plate  IX.), 
which  is  the  general  receptacle  of  the  drift-wood  and  sea-weed  of 
the  Atlantic.  So,  in  like  manner,  to  the  west  from  California  of 
this  other  southwardly  set,  lies  the  pool  into  which  the  drift-wood 
and  sea-weed  of  the  Xorth  Pacific  are  generally  gathered,  but  in 
small  quantities. 

453.  The  natives  of  the  Aleutian  Islands,  where  no  trees  grow, 
depend  upon  the  drift-wood  cast  ashore  there  for  all  the  timber 
used  in  the  construction  of  their  boats,  fishing-tackle,  and  house- 
hold gear.  Among  this  timber,  the  camphor-tree,  and  other  woods 
of  China  and  Japan,  are  said  to  be  often  recognized.  In  this  fact 
we  have  additional  evidence  touching  this  China  Stream,  as  to 
which  (§  451)  but  little,  at  best,  is  known.  "  The  Japanese," 
says  Lieutenant  Bent,*  in  a  paper  read  before  the  American  Geo- 
graphical Society,  January,  1856,  "are  well  aware  of  its  existence, 
and  have  given  it  the  name  of  '  Kuro-Siwo,'  or  Black  Stream, 

*  Lieutenant  Bent  was  in  the  Japan  Expedition  with  Commodore  Perry,  and  used 
the  opportunities  thus  afforded  to  study  the  phenomena  of  this  stream. 


CURRENTS  OF  THE  SEA.  '  1(55 

which  is  iindoiilbteclly  derived  from  the  deep  blue  color  of  its  wa- 
ter, when  compared  witli  that  of  the  adjacent  ocean."  From  this 
we  may  infer  (§  4)  that  the  blue  waters  of  this  China  Stream  also 
contain  more  salt  than  the  neighboring  waters  of  the  sea. 

454.  The  Cold  Cureent  of  Okotsk. — Inshore  of,  but  coun- 
ter to  the  China  current,  along  the  eastern  shores  of  Asia,  is  found 
(§  442)  a  streak,  or  layer,  or  current  of  cold  water  answering  to 
that  between  the  Gulf  Stream  and  the  American  coast.  This 
current,  like  its  fellow  in  the  Atlantic,  is  not  strong  enough  at  all 
times  sensibly  to  affect  the  course  of  navigation ;  but, -like  that 
in  the  Atlantic,  it  is  the  nursery  (§  70)  of  most  valuable  fisheries. 
The  fisheries  of  Japan  are  quite  as  extensive  as  those  of  !N"ew- 
foundland,  and  the  people  of  each  country  are  indebted  for  their 
valuable  supplies  of  excellent  fish  to  the  cold  waters  which  the 
currents  of  the  sea  bring  down  to  their  shores. 

455.  Humboldt's  Current. — The  currents  of  the  Pacific  are 
but  little  understood.  Among  those  about  which  most  is  thought 
to  be  known  is  the  Humboldt  Current  of  Peru,  which  the  great 
and  good  man  whose  name  it  bears  was  the  first  to  discover.  It 
has  been  traced  on  Plate  IX.  according  to  the  best  information — 
defective  at  best — upon  the  subject.  This  current  i^  felt  as  far 
as  the  equator,  mitigating  the  rainless  climate  of  Peru  as  it  goeSy 
and  making  it  delightful.  The  Andes,  with  their  snow-caps,  on 
one  side  of  the  narrow  Pacific  slopes  of  this  inter-tropical  repub- 
lic, and  the  current  from  the  Antartic  regions  on  the  other,  make 
its  climate  one  of  the  most  remarkable  in  the  world ;  for,  though 
torrid  as  to  latitude,  it  is  such  as  to  temperature  that  cloth  clothes 
are  seldom  felt  as  oppressive  during  any  time  of  the  year,  espe- 
cially after  nightfall. 

456.  Between  Humboldt's  Current  and  the  great  equatorial 
flow  there  is  an  area  marked  as  the  "  desolate  region,"  Plate  IX. 
It  was  observed  that  this  part  of  the  ocean  was  rarely  visited  by 
the  whale,  either  sperm  or  right ;  why,  it  did  not  appear ;  but 
observations  asserted  the  fact.  Formerly,  this  part  of  the  ocean 
was  seldom  whitened  by  the  sails  of  a  ship,  or  enlivened  by  the 
presence  of  man.  Xeither  the  industrial  pursuits  of  the  sea  nor 
the  highways  of  commerce  called  him  into  it.     Xow  and  then  a 


IQQ  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

roving  cruiser  or  an  enterprising  whaleman  passed  that  way ;  but 
to  all  else  it  was  an  unfrequented  part  of  the  ocean,  and  so  re- 
mained until  the  gold-Helds  of  Australia  and  the  guano  islands  of 
Peru  made  it  a  thoroughfare.  All  vessels  bound  from  Australia 
to  South  America  now  pass  through  it,  and  in  the  journals  of 
some  of  them  it  is  described  as  a  region  almost  void  of  the  signs 
of  life  in  both  sea  and  air.  In  the  South  Pacific  Ocean  especial- 
ly, where  there  is  such  a  wide  expanse  of  water,  sea-birds  often 
exhibit  a  companionship  with  a  vessel,  and  will  follow  and  keep 
company  with  it  through  storm  and  calm  for  weeks  together. 
Even  those  kinds,  as  the  albatross  and  Cape  pigeon,  that  delight 
in  the  stormy  regions  of  Cape  Horn  and  the  inhospitable  climates 
of  the  Antartic  regions,  not  unfrequently  accompany  vessels  into 
the  perpetual  summer  of  the  tropics. 

The  sea-birds  that  join  the  ship  as  she  clears  Austraha  will,  it 
is  said,  follow  her  to  this  region,  and  then  disappear.  Even  the 
chirp  of  the  stormy-petrel  ceases  to  be  heard  here,  and  the  sea 
itself  is  said  to  be  singularly  barren  of  "  moving  creatures  that 
have  life." 

457.  I  have,  I  believe,  discovered  the  existence  of  a  warm  cur- 
rent from  the  inter-tropical  regions  of  the  Pacific,  midway  between 
the  American  coast  and  the  shore-lines  of  Australia.  This  region 
affords  an  immense  surface  for  evaporation.  No  rivers  empty  into 
it;  the  annual  fall  of  rain,  except  in  the  "Equatorial  Doldrums," 
is  small,  and  the  evaporation  is  all  that  both  the  northeast  and 
the  southeast  trade-winds  can  take  up  and  carry  off.  I  have 
marked  on  Plate  IX.  the  direction  of  the  supposed  warm  water 
cnrrent  which  conducts  these  overheated  and  briny  waters  from 
the  tropics  in  mid  ocean  to  the  extra-tropical  regions  where  pre- 
cipitation is  in  excess.  Here,  being  cooled,  and  agitated,  and 
mixed  up  with  waters  that  are  less  salt,  these  overheated  and 
over-salted  waters  from  the  tropics  may  be  replenished  and  re- 
stored to  their  rounds  in  the  wonderful  system  of  oceanic  circu- 
lation. 

458.  There  arc  also  about  the  equator  in  this  ocean  some  curi- 
ous currents  which  I  do  not  understand,  and  as  to  which  obser- 
vations are  not  sufficient  yet  to  afford  the  proper  explanation  or 


CURRENTS  OF  THE  SEA 


167 

description.  There  are  many  of  them,  some  of  which,  at  times, 
run  with  great  force.  On  a  voyage  from  the  Society  to  the  Sand- 
wich Islands,  I  encountered  one  running  at  the  rate  of  ninety-six 
miles  a  day. 

459.  And  what  else  should  we  expect  in  this  ocean  but  a  sys- 
tem of  currents  and  counter-currents  apparently  the  most  uncer- 
tain and  complicated  ?  The  Pacific  Ocean  and  the  Indian  Ocean 
may,  in  the  view  we  are  about  to  take,  be  considered  as  one  sheet 
of  water.  This  sheet  of  water  covers  an  area  quite  equal  in  ex- 
tent to  one  half  of  that  embraced  by  the  whole  surface  of  the 
earth;  and,  according  to  Professor  Alexander  Keith  Johnston, 
who  so  states  it  in  the  new  edition  of  his  splendid  Physical  Atlas, 
the  total  annual  fall  of  rain  on  the  earth's  surface  is  one  hundred 
and  eighty-six  thousand,  two  hundred  and  forty  cubic  imperial 
miles.  Not  less  than  three  fourths  of  the  vapor  which  makes  this 
rain  comes  from  this  waste  of  waters  ;  but  supposing  that  only 
half  of  this  quantity,  i.  e,,  ninety-three  thousand,  one  hundred  and 
twenty  cubic  miles  of  rain  falls  upon  this  sea,  and  that  that  much, 
at  least,  is  taken  up  from  it  again  as  vapor,  this  would  give  two 
hundred  and  fifty-five  cubic  miles  as  the  quantity  of  water  which 
is  daily  lifted  up  and  poured  back  again  into  this  expanse.  It  is 
taken  up  at  one  place  and  rained  down  at  another,  and  in  this 
process,  therefore,  we  have  agencies  for  multitudes  of  partial  and 
conflicting  currents,  all,  in  their  set  and  strength,  apparently  as 
uncertain  as  the  winds. 

460.  The  better  to  appreciate  the  operation  of  such  agencies  in 
producing  currents  in  the  sea,  now  here,  now  there,  first  this  way, 
and  then  that,  let  us,  by  way  of  illustration,  imagine  a  district  of 
two  hundred  and  fifty-five  square  miles  in  extent  to  be  set  apart, 
in  the  midst  of  the  Pacific  Oceaji,  as  the  scene  of  operations  for 
one  day.  We  must  now  conceive  a  machine  capable  of  pumping 
up,  in  the  twenty-four  hours,  all  the  water  to  the  depth  of  one 
mile  in  this  district.  The  machine  must  not  only  pump  up  and 
bear  ofi"  this  immense  quantity  of  water,  but  it  must  discharge  it 
again  into  the  sea  on  the  same  day,  but  at  some  other  place 
Now  here  is  a  force  for  creating  currents  that  is  equivalent  in  its 
results  to  the  efiects  that  would  be  produced  by  bailing  up,  in 


168  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

twenty-four  hours,  two  hundred  and  fifty-five  cubic  miles  of  wa- 
ter from  one  part  of  the  Pacific  Ocean,  and  emptying  it  out  again 
upon  another  part.  The  currents  that  would  be  created  by  such 
an  operation  would  overwhelm  navigation  and  desolate  the  sea; 
and,  happily  for  the  human  race,  the  great  atmospherical  machine 
which  actually  does  perform  every  day,  on  the  average,  all  this 
lifting  up,  transporting,  and  letting  down  of  water  upon  the  face 
of  the  grand  ocean,  does  not  confine^ itself  to  an  area  of  two  hund- 
red and  fifty-five  square  miles,  but  to  an  area  three  hundred  thou- 
sand times  as  great ;  yet,  nevertheless,  the  same  quantity  of  water 
is  kept  in  motion,  and  the  currents,  in  the  aggregate,  transport  as 
much  water  to  restore  the  equilibrium  as  they  would  have  to  do 
were  all  the  disturbance  to  take  place  upon  our  hypothetical  area 
of  one  mile  deep  over  the  space  of  two  hundred  and  fifty-five 
square  miles.  Now  when  we  come  to  recollect  that  evaporation  is 
lifting  up,  that  the  winds  are  transporting,  and  that  the  clouds  are, 
letting  down  every  day  actually  such  a  body  of  water,  we  are  re- 
minded that  it  is  done  by  little  and  little  at  a  place,  and  by  hair's 
breadths  at  a  time,  not  by  parallelopijDcdons  one  mile  thick — that 
the  evaporation  is  most  rapid  and  the  rains  most  copious,  not  al- 
ways at  the  same  place,  but  now  here,  now  there.  We  thus  see 
actually  existing  in  nature  a  force  perhaps  quite  sufficient  to  give 
rise  to  just  such  a  system  of  currents  as  that  which  mariners  find 
in  the  Pacific — currents  which  appear  to  rise  in  mid  ocean,  run  at 
unequal  rates,  sometimes  east,  sometimes  west,  but  which  always 
lose  themselves  where  they  rise,  viz.,  in  mid  ocean. 

461.  Under  Cureents. — Lieutenant  J.  C.Walsh,  in  the  U.  S. 
schooner  "Taney,"  and  Lieutenant  S.  P.  Lee,  in  the  U.  S.  brig 
"  Dolphin,"  both,  while  they  were  carrying  on  a  system  of  obser- 
vations in  connection  with  the  Wind  and  Current  Charts,  had 
their  attention  directed  to  the  subject  of  submarine  currents. 

462.  They  made  some  interesting  experiments  upon  the  sub- 
ject. A  block  of  wood  was  loaded  to  sinking,  and,  by  means  of 
a  fishing-line  or  a  bit  of  twine,  let  down  to  the  depth  of  one  hund- 
red or  five  hundred  fathoms,  at  the  will  of  the  experimenter.  A 
small  barrel  as  a  float,  just  sufficient  to  keep  the  block  from  sinking 
farther,  was  then  tied  to  the  line,  and  the  whole  let  go  from  the  boat. 


CURRENTS  OF  THE  SEA.  Ig9 

463.  To  use  their  own  expressions,  "It  was  wonderful,  indeed, 
to  see  this  harrerja  move  off,  against  wind,  and  sea,  and  surface 
current,  at  the  rate  of  over  one  knot  an  hour,  as  was  generally  the 
case,  and  on  one  occasion  as  much  as  If  knots.  The  men  in  the 
boat  could  not  repress  exclamations  of  surprise,  for  it  really  ap- 
peared as  if  some  monster  of  the  deep  had  hold  of  the  weight  be- 
low, and  was  walking  off  with  it."*  Both  officers  and  men  were 
amazed  at  the  sight. 

464.  The  experiments  in  deep-sea  soundings  have  also  thrown 
much  light  upon  the  subject  of  under  cuiTcnts.  There  is  reason 
to  believe  that  they  exist  in  all,  or  almost  all  parts  of  the  deep 
sea,  for  never  in  any  instance  yet  has  the  deep-sea  line  ceased  to 
run  out,  even  after  the  plummet  had  reached  the  bottom. 

465.  If  the  line  be  held  fast  in  the  boat,  it  invariably  parts, 
showing,  when  two  or  three  miles  of  it  are  out,  that  the  under- 
currents are  sweeping  against  the  bight  of  it  with  what  seamen 
call  a  siDigging  force^  that  no  sounding  twine  has  yet  proved 
strono;  enouo-h  to  Vv^thstand. 

466.  Lieutenant  J.  P.  Parker,  of  the  United  States  frigate  Con- 
gress, attempted,  in  1852,  a  deep-sea  sounding  off  the  coast  of 
South  America.  He  was  engaged  with  the  experiment  eight  or 
nine  hours,  during  which  time  a  line  nearly  ten  miles  long  was 
paid  out.  Night  coming  on,  he  had  to  part,  the  line  (which  he  did 
simply  by  attempting  to  haul  it  in)  and  return  on  board.  Exam- 
ination proved  that  the  ocean  there,  instead  of  being  over  ten 
miles  in  depth,  was  not  over  three,  and  that  the  line  was  swept 
out  by  the  force  of  one  or  more  under  currents.  But  in  what  di- 
rection these  currents  were  running  is  not  known. 

467.  It  may,  therefore,  without  doing  any  violence  to  the  rules 
of  philosophical  investigation,  be  conjectured,  that  the  equilibrium 
of  all  the  seas  is  preserved,  to  a  greater  or  less  extent,  by  this 
system  of  currents  and  counter-currents  at  and  below  the  sur- 
face. 

If  we  except  the  tides,  and  the  partial  currents  of  the  sea,  such 
as  those  that  may  be  created  by  the  wind,  we  may  lay  it  down  as 
a  rule  (§  31)  that  all  the  currents  of  the  ocean  owe  their  origin  to 

*  Lieutenant  Walsh. 


170       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

difference  of  specific  gravity  between  sea  water  at  one  place  and 
sea  water  at  another ;  for  wherever  there  is  such  a  difference, 
whether  it  be  owing  to  difference  of  temperature  or  to  difference 
of  saltness,  etc.,  it  is  a  difference  that  disturbs  equilibrium,  and 
currents  are  the  consequence.  The  'heavier  water  goes  toward 
the  lighter,  and  the  lighter  whence  the  heavier  comes;  for  two 
fluids  differing  in  specific  gravity  (§  36),  and  standing  at  the  same 
level,  can  no  more  balance  each  other  than  unequal  weights  in  op- 
posite scales.  It  is  immaterial,  as  before  stated,  whether  this  dif- 
ference of  specific  gravity  be  caused  by  temperature,  by  the  matter 
h^d  in  solution,  or  by  any  other  thing ;  the  effect  is  the  same, 
namely,  a  current. 

468.  That  the  sea,  in  all  parts,  holds  in  solution  the  same  kind 
of  solid  matter ;  that  its  waters  in  this  place,  where  it  never  rains, 
are  not  Salter  than  the  strongest  brine  ;  and  that  in  another  place, 
where  the  rain  is  incessant,  they  are  not  entirely  without  salt, 
may  be  taken  as  evidence  in  proof  of  a  system  of  currents  or  of 
circulation  in  the  sea,  by  which  its  waters  are  shaken  up  and  kept 
mixed  together  as  though  they  were  in  a  phial.  Moreover,  we 
may  lay  it  down  as  a  law  in  the  system  of  oceanic  circulation, 
that  every  current  in  the  sea  has  its  counter  current ;  in  other 
words,  that  the  currents  of  the  sea  are,  like  the  nerves  of  the  hu- 
man system,  arranged  in  pairs  ;  for  wherever  one  current  is  found 
carrying  off  water  from  this  or  that  part  of  the  sea,  to  the  same 
part  must  some  other  current  convey  an  equal  volume  of  water, 
or  else  the  first  would,  in  the  course  of  time,  cease  for  the  want 
of  water  to  supply  it. 

469.  CuERENTS  OF  THE  ATLANTIC. — The  principal  currents  of 
the  Atlantic  have  been  described  in  the  chapter  on  the  Gulf  Stream. 
Besides  this,  its  eddies  and  its  offsets,  are  the  equatorial  current 
(Plate  yi.),  and  the  St.  Eoque  or  Brazil  Current.  Their  fountain- 
head  is  the  same.  It  is  in  the  warm  waters  about  the  equator, 
between  Africa  and  America.  The  former,  receiving  the  Amazon 
and  the  Oronoco  as  tributaries  by  the  way,  flows  into  the  Carib- 
bean Sea,  and  becomes,  with  the  waters  (§  34)  in  which  the  vapors 
of  the  trade- winds  leave  their  salts,  the  feeder  of  the  Gulf  Stream. 
The  Brazil  Current,  coming  from  the  same  fountain,  is  supposed 


CURRENTS  OF  THE  SEA.  I7X 

to  be  divided  "by  Cape  St.  Eoque,  one  branch  going  to  the  south 
under  this  name  (Plate  IX.),  the  other  to  the  westward.  This 
last  has  been  a  great  bugbear  to  navigators,  principally  on  account 
of  the  difficulties  which  a  few  dull  vessels  falling  to  leeward  of 
St.  Roque  have  found  in  beating  up  against  it.  It  was  said  to 
have  caused  the  loss  of  some  English  transports  in  the  last  cen- 
tury, which  fell  to  leeward  of  the  Cape  on  a  voyage  to  the  other 
hemisphere ;,  and  navigators,  accordingly,  were  advised  to  shun  it 
as  a  danger. 

470.  This  current  has  been  an  object  of  special  investigation 
during  my  researches  connected  with  the  Wind  and  Current  Charts, 
and  the  result  has  satisfied  me  that  it  is  neither  a  dangerous  nor  a 
constant  current,  notwithstanding  older  writers.  Horsburgh,  in 
his  East  India  Directory,  cautions  navigators  against  it ;  and  Keith 
Johnston,  in  his  grand  Physical  Atlas,  published  in  1848,  thus 
speaks  of  it : 

"  This  current  greatly  impedes  the  progress  of  those  vessels 
which  cross  the  equator  west  of  23°  west  longitude,  impelling 
them  beyond  Cape  St.  E-oque,  when  they  are  drawn  toward  the 
northern  coast  of  Brazil,  and  can  not  regain  their  course  till  after 
weeks  or  months  of  delay  and  exertion." 

471.  So  far  from  this  being  the  case,  my  researches  abundant- 
ly prove  that  vessels  which  cross  the  equator  five  hundred  miles 
to  the  west  of  longitude  23°  have  no  difficulty  on  account  of 
this  current  in  clearing  that  cape.  I  receive  almost  daily  the  ab- 
stract logs  of  vessels  that  cross  the  equator  Avest  of  30°  west,  and 
in  three  days  from  that  crossing  they  are  generally  clear  of  that 
cape.  A  few  of  them  report  the  current  in  their  favor ;  most  of 
them  experience  no  current  at  all ;  but,  now  and  then,  some  do 
find  a  current  setting  to  the  northward  and  westward,  and  oper- 
ating against  them  at  the  rate  of  twenty  miles  a  day.  The  inter- 
tropical regions  of  the  Atlantic,  like  those  of  the  other  oceans 
(§  458),  abound  with  conflicting  currents,  which  no  researches  yet 
have  enabled  the  mariner  to  unravel  so  that  he  may  at  all  times 
know  where  they  are  and  tell  how  they  run,  in  order  that  he  may 
be  certain  of  their  help  when  favorable,  or  sure  of  avoiding  them 
if  adverse. 


172  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

472.  I  may  here  remark,  that  there  seems  to  be  a  larger  flow 
of  polar  waters  into  the  Atlantic  than  of  other  waters  from  it,  and 
I  can  not  account  for  the  preservation  of  the  equilibrium  of  this 
ocean  by  any  other  hypothesis  than  that  which  calls  in  the  aid  of 
under  currents.  They,  I  have  no  doubt,  bear  an  important  part 
in  the  system  of  oceanic  circulation.^' 

*  See  Addenda. 


THE  OPEN  SEA  IN  THE  ARCTIC  OCEAN.  173 


CHAPTER  VIII. 

THE   OPEN    SEA   IN   THE   ARCTIC    OCEAN. 

The  Habit  of  Whalemen,  ^  473. — Right  Whales  can  not  cross  the  Equator,  475. — An 
under  Current  into  the  Polar  Basin,  478. — Indications  of  a  W^arm  Climate,  481. — 
De  Haven's  Water  Sky,  482.— The  open  Sea  of  Dr.  Kane,  484.— Drift  of  an  aban- 
doned Ship,  487. 

473.  It  is  the  custom  among  whalers  to  have  their  harpoons 
marked  with  date  and  the  name  of  the  ship  ;  and  Dr.  Scoresby,  in 
liis  work  on  Arctic  voyages,  mentions  several  instances  of  whales 
that  have  been  taken  near  the  Behring's  Strait  side  with  harpoons 
in  them  bearing  the  stamp  of  shijDS  that  were  known  to  cruise  on 
the  Baffin's  Bay  side  of  the  American  continent;  and  as,  in  one 
or  two  instances,  a  very  short  time  had  elapsed  between  the  date 
of  capture  in  the  Pacific  and  the  date  when  the  fish  must  have 
been  struck  on  the  Atlantic  side,  it  was  argued  therefore  that  there 
was  a  northwest  passage  by  which  the  whales  passed  from  one 
side  to  the  other,  since  the  stricken  animal  could  not  have  had  the 
harpoon  in  him  long  enough  to  admit  of  a  passage  around  either 
Cape  Horn  or  the  Cape  of  Good  Hope. 

474.  The  whale-fishing  is,  among  the  industrial  pursuits  of  the 
sea,  one  of  no  little  importance ;  and  when  the  system  of  investi- 
gation out  of  which  the  "wind  and  current  charts"  have  grown 
was  commenced,  the  haunts  of  this  animal  did  not  escape  atten- 
tion or  examination.  The  log-books  of  whalers  were  collected  in 
great  numbers,  and  patiently  examined,  co-ordinated,  and  discuss- 
ed, in  order  to  find  out  what  parts  of  the  ocean  are  frequented  by 
this  kind  of  whale,  what  parts  by  that,  and  what  parts  by  neither. 
(See  Plate  IX.) 

475.  Log-books  containing  the  records  by  different  ships  for 
hundreds  of  thousands  of  days  were  examined,  and  the  observa- 
tions in  them  co-ordinated  for  this  chart.  And  this  investigation, 
as  Plate  IX.  shows,  led  to  the  discovery  that  the  tropical  regions 
of  the  ocean  are  to  the  right  whale  as  a  sea  of  fire,  through  which 
he  can  not  pass,  and  into  which  he  never  enters.     The  fact  was 


174  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

also  brought  out  that  the  same  kind  of  whale  that  is  found  off  the 
shores  of  Greenland,  in  Baffin's  Bay,  etc.,  is  found  also  in  the 
North  Pacific,  and  about  Behring's  Strait,  and  that  the  right 
whale  of  the  northern  hemisphere  is  a  different  animal  from  that 
of  the  southern. 

476.  Thus  the  fact  was  established  that  the  harpooned  whales 
did  not  pass  around  Cape  Horn  or  the  Cape  of  Good  Hope,  for 
they  were  of  the  class  that  could  not  cross  the  equator.  In  this 
way  we  were  furnished  with  circumstantial  evidence  affording  the 
most  irrefragable  proof  that  there  is,  at  times  at  least,  open  water 
communication  through  the  Arctic  Sea  from  one  side  of  the  con- 
tinent to  the  other,  for  it  is  known  that  the  whales  can  not  travel 
under  the  ice  for  such  a  great  distance  as  is  that  from  one  side  of 
this  continent  to  the  other. 

477.  But  this  did  not  prove  the  existence  of  an  open  sea  there; 
it  only  established  the  existence — the  occasional  existence,  if  you 
please — of  a  channel  through  which  whales  had  passed.  There- 
fore we  felt  bound  to  introduce  other  evidence  before  we  could 
expect  the  reader  to  admit  our  proof,  and  to  believe  with  us  in  the 
existence  of  an  open  sea  in  the  Arctic  Ocean. 

478.  There  is  an  under  current  setting  from  the  Atlantic  through 
Davis's  Strait  into  the  Arctic  Ocean,  and  there  is  a  surface  cur- 
rent setting  out.  Observations  have  pointed  out  the  existence  of 
this  under  current  there,  for  navigators  tell  of  immense  icebergs 
which  they  have  seen  drifting  rapidly  to  the  north,  and  against  a 
strong  surface  current.  These  icebergs  were  high  above  the  wa- 
ter, and  their  depth  below,  supposing  them  to  be  parallelepipeds, 
was  seven  times  greater  than  their  height  above.  JSTo  doubt  they 
w^ere  drifted  by  a  powerful  under  current. 

479.  Now  this  under  current  comes  from  the  south,  where  it  is 
warm,  and  the  temperature  of  its  waters  is  perhaps  not  below  32° ; 
at  any  rate,  they  are  comparatively  warm.  There  must  be  a  place 
somewhere  in  the  Arctic  seas  wdiere  this  under  current  ceases  to 
flow  north,  and  begins  to  flow  south  as  a  surface  current ;  for  the 
surface  current,  though  its  waters  are  mixed  with  the  fresh  waters 
of  the  rivers  and  of  precipitation  in  the  polar  basin,  nevertheless 
bears  out  vast  quantities  of  salt,  which  is  furnished  neither  by  the 
rivers  nor  the  rains. 


THE  OPEN  SEA  IN  THE  ARCTIC  OCEAN.  175 

Tliese  salts  are  supplied  by  the  under  current ;  for  as  much  salt 
as  one  current  brings  in,  other  currents  must  take  out,  else  the 
polar  basin  would  become  a  basin  of  salt ;  and  where  the  under 
current  transfers  its  waters  to  the  surface,  there  is,  it  is  supposed, 
a  basin  in  which  the  waters,  as  they  rise  to  the  surface,  are  at  30°, 
or  whatever  be  the  temperature  of  the  under  current,  which  we 
know  must  be  above  the  freezing  point,  for  the  current  is  of  water 
in  a  fluid,  not  in  a  solid  state. 

480.  An  arrangement  in  nature,  by  which  a  basin  of  consider- 
able area  in  the  frozen  ocean  could  be  supplied  by  water  coming 
in  at  the  bottom  and  rising  up  at  the  top,  with  a  temperature  not 
below  30°,  or  even  28° — the  freezing  point  of  sea  water — would 
go  far  to  mitigate  the  climate  in  the  regions  round  about. 

481.  And  that  there  is  a  warmer  climate  somewhere  in  that  in- 
hospitable sea,  the  observations  of  many  of  the  explorers  who  have 
visited  it  indicate.  Its  existence  may  be  inferred  also  from  the 
well-known  fact  that  the  birds  and  animals  are  found  at  certain 
seasons  migrating  to  the  north,  evidently  in  search  of  milder  cli- 
mates. The  instincts  of  these  dumb  creatures  are  unerring:,  and 
we  can  imagine  no  mitigation  of  the  climate  in  that  direction,  un- 
less it  arise  from  the  proximity  or  the  presence  there  of  a  large 
body  of  open  water.  It  is  another  furnace  (§  62)  in  the  beautifiil 
economy  of  Nature  for  tempering  climates  there. 

482.  Eelying  upon  a  process  of  reasoning  like  this,  and  the  de- 
ductions flowing  therefrom.  Lieutenant  De  Haven,  when  he  went 
in  command  of  the  American  expedition  in  search  of  Sir  John 
Franklin  and  his  companions,  was  told,  in  his  letter  of  instruc- 
tions, to  look,  when  he  should  get  well  up  into  Wellington  Chan- 
nel, for  an  open  sea  to  the  northward  and  westward.  He  looked, 
and  saw  in  that  direction  a  "water  sky."  Captain  Penny  after- 
ward went  there,  found  open  wa^er,  and  sailed  upon  it. 

483.  The  open  sea  in  the  Arctic  Ocean  is  probably  not  always 
in  the  same  place,  as  the  Gulf  Stream  (§  56)  is  not  always  in  one 
place.  It  probably  is  always  where  the  waters  of  the  under  cur- 
rent are  brought  to  the  surface  ;  and  this,  we  may  imagine,  would 
depend  upon  the  freedom  of  ingress  for  the  under  current.  Its 
course  may,  perhaps,  be  modified  more  or  less  by  the  ice  on  the 
surface,  by  changes,  from  whatever  cause,  in  the  course  or  velocity 


176  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

of  the  surface  current,  for  obviously  the  under  current  could  not 
brins"  more  water  into  the  frozen  ocean  than  the  surface  current 
would  carry  out  again,  either  as  ice  or  water. 

Every  winter,  an  example  of  how  very  close  warm  water  in  the 
sea  and  a  very  severe  climate  on  the  land  or  the  ice  may  be  to 
each  other,  is  afforded  to  us  in  the  case  of  the  Gulf  Stream  and 
tlie  Labrador-like  climate  of  New  England,  Nova  Scotia,  and  New-. 
foundland.  In  these  countries,  in  winter,  the  thermometer  fre- 
quently sinks  far  below  zerb,  notwithstanding  that  the  tepid  wa- 
ters of  the  Gulf  Stream  may  be  found  with  their  summer  temper- 
ature within  one  good  day's  sail  of  these  very,  very  cold  places. 

484.  Dr.  Kane  reports  an  open  sea  north  of  the  parallel  of  82°. 
To  reach  it,  his  party  crossed  a  barrier  of  ice  80  or  100  miles  broad. 
Before  gaining  this  open  water,  he  found  the  thermometer  to  show 
the  extreme  temperature  of  —  60°.  Passing  this  ice-bound  region 
by  traveling  north,  he  stood  on  the  shores  of  an  iceless  sea,  ex- 
tending in  an  unbroken  sheet  of  water  as  far  as  the  eye  could  reach 
toward  the  pole.  Its  waves  were  dashing  on  the  beach  with  the 
swell  of  a  boundless  ocean.  The  tides  ebbed  and  flowed  in  it, 
and  I  apprehend  that  the  tidal  wave  from  the  Atlantic  can  no  more 
pass  under  this  icy  barrier  to  be  propagated  in  seas  beyond,  than 
the  vibrations  of  a  musical  string  can  pass  with  its  notes  a  fret  upon 
which  the  musician  has  placed  his  finger.  The  swell  of  the  sea  can 
not  pass  wide  fields  or  extensive  barriers  of  ice,  for  De  Haven,  dur- 
ing his  long  imprisonment  and  drift  (§  530),  found  the  ice  so  firm 
that  he  observed  regularly  from  an  artificial  horizon  placed  upon  it, 
and  found  the  mercury  always  "perfectly  steady."  These  tides, 
therefore,  must  have  been  born  in  that  cold  sea,  having  their  cra- 
dle about  the  North  Pole.  If  these  statements  and  deductions  be 
correct,  then  we  infer  that  most,  if  not  all  the  unexplored  regions 
about  the  pole  are  covered  with  deep  water ;  for,  were  this  unex- 
pected area  mostly  land  or  shallow  water,  it  could  not  give  birth 
to  regular  tides.  Indeed,  the  existence  of  these  tides,  with  the  im- 
mense flow  and  drift  which  annually  take  place  from  the  Polar 
seas  into  the  Atlantic,  suggests  many  conjectures  concerning  the 
condition  of  these  unexplored  regions.  Whalemen  have  always 
been  puzzled  as  to  the  place  of  breeding  for  the  right  whale.     It 


THE  OPEN  SEA  IN  THE  ARCTIC  OCEAN.  177 

is  a  cold-water  animal,  and,  following  up  this  train  of  thought,  the 
question  is  prompted,  Is  the  nursery  for  the  great  whale  in  this 
Polar  sea,  which  has  been  so  set  about  and  hemmed  in  with  a 
hedge  of  ice  that  man  may  not  trespass  there?  This  providential 
economy  is  still  farther  suggestive,  prompting  us  to  ask.  Whence 
comes  the  food  for  the  young  Avhales  there?  Do  the  teeming 
waters  of  the  Gulf  Stream  (§  74)  convey  it  there  also,  and  in  chan- 
nels so  far  down  in  the  depths  of  the  sea  that  no  enemy  may  way- 
lay and  spoil  it  on  the  long  journey  ? 

485.  Seals  were  sporting  and  water-fovfl  feeding  in  this  open 
sea  of  Dr.  Kane's.  Its  waves  came  rolling  in  at  his  feet,  and  dash- 
ed with  measured  tread,  like  the  majestic  billows  of  old  ocean, 
against  the  shore.  Solitude,  the  cold  and  boundless  expanse,  and 
the  mysterious  heavings  of  its  green  waters,  lent  their  charm  to 
the  scene.  They  suggested  fancied  myths,  and  kindled  in  the  ar- 
dent imaginatioii  of  the  daring  mariners  many  longings. 

486.  The  temperature  of  its  waters  was  only  36° !  Such  warm 
water  could  get  there  from  the  south  only  as  a  current  far  down 
in  the  depths  below.  The  bottom  of  the  ice  of  this  eighty  miles 
of  barrier  was  no  doubt  many — perhaps  hundreds  of — feet  below 
the  surface  level.  Under  this  ice  there  was  also  doubtless  water 
above  the  freezing  point. 

Nor  need  the  presence  of  warm  water  within  the  Arctic  circle 
excite  surprise,  when  we  recollect  that  the  cold  waters  of  the 
frigid  zone  are  transferred  to  the  torrid  without  changing  their 
temperature  perhaps  more  than  7°  or  8°  by  the  way.  This  trans- 
fer of  cold  waters  for  a  part  of  the  way  may  take  place  on  the  sur- 
face, and  until  the  polar  flow  (§  14)  dips  down  and  becomes  sub- 
marine. At  any  rate.  Professor  Bache  reports  that  his  assistants 
on  the  Coast  Survey  have  found  water  at  the  bottom  of  the  Gulf 
Stream,  in  latitude  25°  30^  N.,  as  low  in  temperature  as  35°. 
Now,  if  water  flowing  out  of  the  polar  basin  at  the  temperature  of 
28°  may,  by  passing  along  the  secret  paths  of  the  sea,  reach  the 
Gulf  of  Mexico  in  summer  at  a  tem2)erature  of  only  3°  above  the 
freezing  point,  why  may  not  water,  leaving  the  torrid  zone  at  a 
temperature  of  85°,  and  traveling  by  the  same  hidden  ways,  reach 
the  frigid  zone  at  the  temperature  of  36°  ? 


178  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

487.  At  the  very  time  that  the  doctor  was  gazing  with  longing 
eyes  upon  these  strange,  green  waters,  there  is  known  to  have  been 
a  powerful  drift  setting  out  from  another  part  of  this  Polar  sea,  and 
carrying  with  it  from  its  mooring  the  English  exploring  ship  Res- 
olute, which  Captain  Kellett  had  abandoned  fast  bound  in  the  ice 
several  winters  before.  This  drift  carried  a  field  of  ice  that  cov- 
ered an  area  not  less  than  300,000  square  miles,  through  a  dis- 
tance of  a  thousand  miles  to  the  south.  The  drift  of  this  ship 
was  a  repetition  of  De  Haven's  celebrated  drift  (§  530) ;  for  in 
each  case  the  ice  in  which  the  vessel  was  fastened  floated  out  and 
carried  the  vessel  along  with  it :  by  which  I  mean  to  be  understood 
as  wishing  to  convey  the  idea  that  the  vessel  was  not  drifted 
through  a  line  or  an  opening  in  the  ice,  but,  remaining  fast  in  the 
ice,  she  was  carried  along  with  the  whole  icy  field  or  waste. 

488.  This  field  of  ice  averaged  a  thickness  of  not  less  than 
seven  feet ;  at  least  that  was  the  case  with  De  Haven.  A  field 
of  ice  covering  to  the  depth  of  seven  feet  an  area  of  300,000  square 
miles,  would  weigh  not  less  than  18,000,000,000  tons.  This, 
then,  is  the  quantity  of  solid  msdiev  that  is  drifted  out  of  the  Polar 
Seas  through  one  opening — Davis's  Straits  alone — and  during  a 
part  of  the  year  only.  The  quantity  of  water  which  was  required 
to  float  and  drive  this  solid  matter  out  was  probably  many  times 
greater  than  this.  A  quantity  of  water  equaj  in  weight  to  these 
two  masses  had  to  go  in.  The  basin  to  receive  these  inflowing 
waters,  i.  e.,  the  unexplored  basin  about  the  North  Pole,  includes 
an  area  of  a  million  and  a  half  square  miles  ;  and  as  the  outflow- 
ing ice  and  water  are  at  the  surface,  the  return  current  must  be 
submarine.  A  part  of  the  water  that  it  bears  probably  flows  in 
beneath  Dr.  Kane's  barrier  of  ice  (§  484). 

These  two  currents,  therefore,  it  may  be  perceived,  keep  in  mo- 
tion between  the  temperate  and  polar  regions  of  the  earth  a  vol- 
ume of  water,  in  comparison  with  which  the  mighty  Mississippi, 
in  its  greatest  floods,  sinks  down  to  a  mere  rill. 

489.  On  the  borders  of  this  ice-bound  sea  Dr.  Kane  found  sub- 
sistence for  his  party — another  proof  of  the  high  temperature  and 
comparative  mildness  of  its  climate. 


THE  SALTS  OF  THE  SEA.  179 


CHAPTER  IX. 

THE    SALTS   OF   THE   SEA. 

Why  is  the  Sea  Saltl  <J  49L— An  Hypothesis,  494.— The  Adaptations  of  the  Sea,  498. 
— Components  of  Sea  Water  every  where  alike,  500. — Proportion  of  soHd  Contents, 
502. — The  Influence  of  Wind  upon  the  Circulation  of  the  Sea,  508. — The  Influence 
of  Heat,  511. — The  Influence  of  Evaporation,  517. — The  Influence  of  Precipitation, 
519. — Under  Current  from  the  Mediterranean  and  Red  Sea  due  to  the  Salts  of,  523. 
— Space  that  the  Salts  of  the  Sea  would  occupy  in  a  Solid  State,  527. — De  Haven's 
Drift  from  the  Arctic  Ocean,  530. — An  under  Current  flowing  into  it,  534. — The 
Water  Sky,  540. — Sea  Shells,  545. — Their  Agency  in  the  System  of  Oceanic  Circu- 
lation, 548. — They  assist  to  regulate  Climate,  557. — Compensation  in  the  Sea,  563. 
— Insects  of  the  Sea,  565. — Geological  Records  concerning  the  Salts  of  the  Sea, 
568.— Light  from  the  Bible,  571. — Whence  come  the  Salts  of  the  Seal  574.— Pro- 
fessor Chapman's  Experiments,  579. 

490.  In  order  to  comprehend  aright  the  currents  of  the  sea,  and 
to  study  with  advantage  its  physical  adaptations,  it  is  necessary  to 
understand  the  effects  produced  by  the  salts  of  the  sea  upon  the 
equilibrium  of  its  waters  ;  for  wherever  equilibrium  be  destroyed, 
whether  in  the  air  or  water,  it  is  restored  by  motion,  and  motion 
among  fluid  particles  gives  rise  to  currents,  which,  in  turn,  consti- 
tute circulation. 

This  chapter  is  therefore  added  as  a  sort  of  supplement,  which 
will  assist  us  in  elucidating  what  has  been  advanced  concerning 
the  currents  of  the  sea. 

491.  The  question  is  often  asked,  "Why  is  the  sea  salt?"  I 
think  it  can  be  shown  that  the  circulation  of  the  ocean  depends, 
in  a  great  measure,  upon  the  salts  of  sea  water ;  certainly  its  in- 
flences  upon  climate  are  greatly  extended  by  reason  of  its  salt- 
ness. 

492.  As  a  general  rule,  the  sea  is  nearly  of  a  uniform  degree  of 
saltness,  and  the  constituents  of  sea  water  are  as  constant  in  their 
proportions  as  are  the  components  of  the  atmosphere.  It  is  true 
that  we  sometimes  come  across  arms  of  the  sea,  or  places  in  the 
ocean,  where  we  find  the  water  more  salt  or  less  salt  than  sea 

M 


180  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

water  is  generally  ;  but  this  circumstance  is  clue  to  local  causes 
of  easy  explanation.  For  instance  :  when  we  come  to  an  arm  of 
the  sea,  as  the  Red  Sea  (§  404),  upon  which  it  never  rains,  and 
from  which  the  atmosphere  is  continually  abstracting,  by  evapor- 
ation, fresh  water  from  the  salt,  we  may  naturally  expect  to  find 
a  greater  proportion  of  salt  in  the  sea  water  that  remains  than  we 
do  near  the  mouth  of  some  great  river,  as  tlie  Amazon,  or  in  the 
regions  of  constant  precipitation,  or  other  parts  where  it  rains 
more  than  it  evaporjites.  Therefore  we  do  not  find  sea  water 
from  all  parts  of  the  ocean  actually  of  the  same  degree  of  salt- 
ness,  yet  we  do  find,  as  in  the  case  of  the  E-ed  Sea,  sea  water  that 
is  continually  giving  off  to  evaporation  fresh  water  in  large  quan- 
tities ;  nevertheless,  for  such  water  there  is  a  degree,  and  a  very 
moderate  degree,  of  saltness  which  is  a  maximum ;  and  we  more- 
over find  that,  though  the  constituents  of  sea  water,  like  those  of 
the  atmosphere,  are  not  for  every  place  invariably  the  same  as  to 
their  proportions,  yet  they  are  the  same,  or  nearly  the  same,  as  to 
their  character.  v 

493.  When,  therefore,  we  take  into  consideration  the  fact  that, 
as  a  general  rule,  sea  water  is,  with  the  exceptions  above  stated, 
every  where  and  always  the  same,  and  that  it  can  only  be  made 
so  by  being  well  shaken  together,  we  find  grounds  on  which  to 
base  the  conjecture  that  the  ocean  has  its  system  of  circulation, 
which  is  probably  as  complete  and  not  less  wonderful  than  is  the 
circulation  of  blood  through  the  human  system. 

494.  In  order  to  investigate  the  currents  of  the  sea,  and  to 
catch  a  glimpse  of  the  laws  by  which  the  circulation  of  its  Avaters 
is  governed,  hypothesis,  in  the  present  meagre  state  of  absolute 
knowledge  with  regard  to  the  subject,  seems  to  be  as  necessary  to 
progress  as  is  a  corner-stone  to  a  building.  To  make  progress 
with  such  investigations,  we  want  something  to  build  upon.  In 
the  absence  of  facts,  we  are  sometimes  permitted  to  suppose  them; 
only,  in  supposing  them,  we  should  take  not  only  the  possible, 
but  the  probable ;  and  in  making  the  selection  of  the  various  hy- 
potheses which  are  suggested,  we  are  bound  to  prefer  that  one  by 
which  the  greatest  number  of  phenomena  can  be  reconciled. 
When  we  have  found,  tried,  and  offered  such  an  one,  we  are  en- 


THE  SALTS  OF  THE  SEA. 


181 


titled  to  claim  for  it  a  respectful  consideration  at  least,  until  we 
discover  it  leading  us  into  some  palpable  absurdity,  or  untU  some 
other  hypothesis  be  suggested  which  will  account  equally  as  well, 
but  for  a  greater  number  of  phenomena.  Then,  as  honest  search- 
ers after  truth,  we  should  be  ready  to  give  up  the  former,  adopt 
the  latter,  and  hold  it  until  some  other  better  than  either  of  the 
two  be  offered. 

495.  With  this  understanding,  I  venture'  to  offer  an  hypothesis 
with  regard  to  the  agency  of  the  salts  or  solid  matter  of  the  sea 
in  imparting  dynamical  force  to  the  waters  of  the  ocean,  and  to 
suggest  that  one  of  the  purposes  which,  in  the  gTand  design,  it  was 
probably  intended  to  accomplish  by  having  the  sea  salt,  and  not 
fresh,  was  to  impart  to  its  waters  the  forces  and  powers  necessary 
to  make  their  circulation  complete. 

496.  In  the  first  place  we  do  but  conjecture  when  we  say  that 
there  is  a  set  of  currents  in  the  sea  by  which  its  waters  are  con- 
veyed from  place  to  place  with  regularity,  certainty,  and  order. 
But  this  conjecture  appears  to  be  founded  on  reason ;  for  if  we 
take  a  sample  of  water  which  shall  fairly  represent,  in  the  propor- 
tion of  its  constituents,  the  average  water  of  the  Pacific  Ocean, 
and  analyze  it,  and  if  we  do  the  same  by  a  similar  sample  from 
the  Atlantic,  we  shall  find  the  analysis  of  the  one  to  resemble  that 
of  the  other  as  closely  as  though  the  two  samples  had  been  taken 
from  the  same  bottle  after  having  been  well  shaken.  How,  then, 
shall  we  account  for  this,  unless  upon  the  supposition  that  sea 
water  from  one  part  of  the  world  is,  in  the  process  of  time,  brought 
into  contact  and  mixed  up  with  sea  water  from  all  other  parts  of 
the  world  ?  Agents,  therefore,  it  would  seem,  are  at  work,  which 
shake  up  the  waters  of  the  sea  as  though  they  were  in  a  bottle, 
and  which,  in  the  course  of  time,  mingle  those  that  are  in  one  part 
of  the  ocean  with  those  that  are  in  another  as  thoroughly  and  com- 
pletely as  it  is  possible  for  man  to  do  in  a  vessel  of  his  own  con- 
struction. 

497.  This  fact,  as  to  uniformity  of  components,  appears  to  call 
for  the  hypothesis  that  sea  water  which  to  day  is  in  one  part  of 
the  ocean,  will,  in  the  process  of  time,  be  found  in  another  part 
the  most  remote.      It  must,  therefore,  be  carried  about  by  cur- 


1S2       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

rents ;  and  as  these  currents  have  their  offices  to  perform  in  •  the 
terrestrial  economy,  they  probably  do  not  flow  by  chance,  but  in 
obedience  to  physical  laws  ;  they  no  doubt,  therefore,  maintain 
the  order  and  preserve  the  harmony  wdiich  characterize  every  de- 
partment of  God's  handy-work,  upon  the  threshold  of  which  man 
has  as  yet  been  permitted  to  stand,  to  observe,  or  to  comprehend. 
498-  I^ay,  having  reached  this  threshold,  and  taken  a  survey 
of  the  surrounding  ocean,  we  are  ready  to  assert,  with  all  the  con- 
fidence of  knowledge,  that  the  sea  has  a  system  of  circulation  for 
its  waters.  We  rest  this  assertion  upon  our  faith  in  the  physical 
adaptations  with  which  the  sea  is  invested.  Take,  for  example,  the 
coral  islands,  reefs,  beds,  and  atolls  with  which  the  Pacific  Ocean 
is  studded  and  garnished.  They  were  built  up  of  materials  which 
a  certain  kind  of  insect  quarried  from  the  sea  water.  The  cur- 
rents of  the  sea  ministered  to  this  little  insect — they  were  its  hod 
carriers.  When  fresh  supplies  of  solid  matter  were  wanted  for  the 
coral  rock  upon  which  the  foundations  of  the  Polynesian  Islands 
were  laid,  these  hod  carriers  brought  them  in  unfailing  streams  of 
sea  water,  loaded  with  food  and  building  materials  for  the  coralline ; 
the  obedient  currents  thread  the  widest  and  the  deepest  seas. 
They  never  fail  to  come  at  the  right  time,  nor  refuse  to  go ;  for, 
unless '  the  currents  of  the  sea  were  employed  to  cany  off  from 
this  insect  the  waters  that  have  been  emptied  by  it  of  their  lime, 
and  to  bring  to  it  others  charged  with  more,  it  is  evident  the  lit- 
tle creature  v/ould  have  perished  for  want  of  food  long  before  its 
task  was  half  completed.  But  for  currents,  it  would  have  been 
impaled  in  a  nook  of  the  very  drop  of  water  in  which  it  was 
spawned ;  for  it  would  have  soon  secreted  the  lime  contained  in 
this  drop  of  water,  and  then,  without  the  ministering  aid  of  cur- 
rents to  bring  it  more,  it  would  have  perished  for  the  want  of  food 
for  itself  and  materials  for  its  edifice  ;  and  thus,  but  for  the  benign 
currents  which  took  this  exhausted  water  away,  there  we  perceive 
this  emptied  drop  would  have  remained,  not  only  as  the  grave  of 
the  little  architect,  but  as  a  monument  in  attestation  of  the  shock- 
ing monstrosity  that  there  had  been  a  failure  in  the  sublime  sys- 
tem of  terrestrial  adaptations — that  the  sea  had  not  been  adapted 
by  its  Creator  to  the  well-being  of  all  its  inhabitants.  Now  we 
do  know  that  its  adaptations  are  suited  to  all  the  wants  of  every 


THE  SALTS  OF  THE  SEA.  I33 

one  of  its  inhabitants — to  the  wants  of  the  coral  insect  as  well  as 
to  those  of  the  whale.  Hence  we  say  im  know  that  the  sea  has 
its  system  of  circulation,  for  it  transports  materials  for  the  coral 
rock  from  one  part  of  the  world  to  another ;  its  currents  receive 
them  from  the  rivers,  and  hand  them  over  to  the  little  mason  for 
the  structure  of  the  most  stupendous  works  of  solid  masonry  that 
man  has  ever  seen — the  coral  islands  of  the  sea. 

499.  Thus,  by  a  process  of  reasoning  which  is  perfectly  philo- 
sophical, Ave  are  irresistibly  led  to  conjecture  that  there  are  regular 
and  certain,  if  not  appointed  channels,  through  which  the  water 
travels  from  one  part  of  the  ocean  to  another,  and  that  those  chan- 
nels belong  to  an  arrangement  which  may  make,  and,  for  aught 
w^e  know  to  the  contrary,  which  does  make  the  system  of  oceanic 
circulation  as  complete,  as  perfect,  and  as  harmonious  as  is  that 
of  the  atmosphere  or  the  blood.  Every  drop  of  water  in  the  sea 
is  as  obedient  to  law  and  order  as  are  the  members  of  the  heaven- 
ly host  vn  the  remotest  regions  of  space.  For  when  the  morning 
stars  sang  together  in  the  almighty  anthem,  "  the  waves  also  lift- 
ed up  their  voice ;"  and  doubtless,  therefore,  the  harmony  in  the 
depths  of  the  ocean  is  in  tune  with  that  which  comes  from  the 
spheres  above.  We  can  not  doubt  it ;  for,  were  it  not  so,  were 
there  no  channels  of  circulation  from  one  ocean  to  another,  and  if, 
accordingly,  the  waters  of  the  Atlantic  were  confined  to  the  At- 
lantic, or  if  the  waters  of  the  arms  and  seas  of  the  Atlantic  were 
confined  to  those  arms  and  seas,  and  had  no  channels  of  circula- 
tion by  which  they  could  pass  out  into  the  ocean,  and  traverse 
different  latitudes  and  climates — if  this  were  so,  then  the  machin- 
ery of  the  ocean  would  be  as  incomplete  as  that  of  a  watch  with- 
out a  balance-wheel;  for  the  waters  of  these  arms  and  seas  would, 
as  to  their  constituents,  become,  in  the  process  of  time,  very  dif- 
ferent from  the  sea  waters  in  other  parts  of  the  world,  and  their 
inhabitants  would  perish  for  the  want  of  brine  of  the  right  strength 
or  of  water  of  the  right  temperature. 

500.  For  instance,  take  the  Red  Sea  and  the  ^lediterranean  by 
way  of  illustration.  Upon  the  Red  Sea  there  is  no  precipitation  ; 
it  is  a  rainless  region ;  not  a  river  runs  down  to  it,  not  a  brook 
empties  into  it ;  therefore  there  is  no  process  by  which  the  salts 
and  washings  of  the  earth,  which  are  taken  up  and  held  in  solution 


184  THE  PHYSICAL  GEOGRAPHY  OF  THF  SEA. 

bj  rain  or  river  water,  can  be  brought  down  into  the  Eed  Sea. 
Its  salts  come  from  the  ocean,  and  the  air  takes  up  from  it,  in  the 
process  of  evajDoration,  fresh  water,  leaving  behind,  for  the  cur- 
rents to  carry  awaj,  the  solid  matter  which,  as  sea  water,  it  held 
in  solution. 

501.  On  the  other  hand,  numerous  rivers  discharge  themselves 
into  the  Mediterranean,  some  of  which  are  filtered  through  soils  and 
among  minerals  which  yield  one  kind  of  salts  or  soluble  matter,  an- 
other river  runs  through  a  limestone  or  volcanic  region  of  country, 
and  brings  down  in  solution  solid  matter — it  may  be  common  salt, 
sulphate  or  carbonate  of  lime,  magnesia,  soda,  potash,  or  iron — 
either  or  all  may  be  in  its  waters.  Still,  the  constituents  of  sea 
water  from  the  Mediterranean  and  of  sea  water  from  the  Red  Sea 
are  quite  the  same.  But  the  waters  of  the  Dead  Sea  have  no  con- 
nection with  those  of  the  ocean ;  they  are  cut  off  from  its  channels 
of  circulation,  and  are  therefore  quite  different,  as  to  their  compo- 
nents, from  any  arm,  frith,  or  gulf  of  the  broad  ocean.  Its  inhab- 
itants are  also  different  from  those  of  the  hio-h  seas. 

502.  "  The  solid  constituents  of  sea  water  amount  to  about  3| 
per  cent,  of  its  weight,  or  nearly  half  an  ounce  to  the  pound.  Its 
saltness  may  be  considered  as  a  necessary  result  of  the  present 
order  of  things.  Rivers  which  are  constantly  flowing  into  the 
ocean  contain  salts,  varying  from  ten  to  fifty,  and  even  one  hund- 
red grains  per  gallon.  They  are  chiefly  common  salt,  sulphate  and 
carbonate  of  lime,  magnesia,*  soda,  potash,  and  iron ;  and  these 
are  found  to  constitute  the  distinguishing  characteristics  of  sea 
water.  The  water  which  evaporates  from  the  sea  is  nearly  pure, 
containing  but  very  minute  traces  of  salts.  Falling  as  rain  upon 
the  land,  it  washes  the  soil,  percolates  through  the  rocky  layers, 
and  becomes  charged  with  saline  substances,  which  are  borne  sea- 
ward by  the  returning  currents.  The  ocean,  therefore,  is  the  great 
depository  of  every  thing  that  water  can  dissolve  and  carry  down 
from  the  surface  of  the  continents ;  and,  as  there  is  no  channel  for 
their  escape,  they  of  course  consequently  accumulate,  "f     They 

*  It  is  the  chloride  of  magnesium  which  gives  that  clamp,  sticky  feeling  to  the 
clothes  of  sailors  that  are  washed  or  wetted  with  salt  water, 
t  Youman's  Chemistry. 


THE  SALTS  OF  THE  SEA.  185 

would  constantly  accumulate,  as  tliis  very  shrewd  author  remarks, 
were  it  not  for  the  shells  and  insects  of  the  sea  and  other  agents 
mentioned. 

503.  "  The  case  of  the  sea,"  says  Fowner,  "  is  but  a  magnified 
representation  of  what  occurs  in  every  lake  into  which  rivers  flow, 
but  from  which  there  is  no  outlet  except  by  evaporation.  Such 
a  lake  is  invariably  a  salt  lake.  It  is  impossible  that  it  can  be 
otherwise ;  and  it  is  curious  to  observe  that  this  condition  disap- 
pears when  an  artificial  outlet  is  produced  for  the  waters." 

504.  How,  therefore,  shall  we  account  for  this  sameness  of 
compound,  this  structure  of  coral  (§  498),  this  stability  as  to  ani- 
mal life  in  the  sea,  but  upon  the  supposition  of  a  general  system 
of  circulation  in  the  ocean,  by  which,  in  process  of  time,  water 
from  one  part  is  conveyed  to  another  part  the  most  remote,  and 
by  which  a  general  interchange  and  commingling  of  the  waters 
take  place  ?  In  like  manner,  the  constituents  of  the  atmosphere, 
whether  it  be  analyzed  at  the  equator  or  the  poles,  are  the  same. 
By  cutting  off  and  shutting  up  from  the  general  channels  of  cir- 
culation any  portion  of  sea  water,  as  in  the  Dead  Sea,  or  of  at- 
mospheric air,  as  in  mines  or  wells,  we  can  easily  fill  either  with 
gases  or  other  matter  that  shall  very  much  affect  its  character, 
or  alter  the  proportion  of  its  ingredients,  and  affect  the  health  of 
its  inhabitants ;  but  in  the  open  sea  or  open  air,  no. 

505.  The  principal  agents  that  are  supposed  to  be  concerned  in 
giving  circulation  to  the  atmosphere,  and  in  preserving  the  ratio 
among  its  components,  are  light,  heat,  electricity,  and  magnetism. 
But  with  regard  to  the  sea,  it  is  not  known  what  office  is  perform- 
ed by  electricity  and  magnetism,  in  giving  dynamical  force  to  its 
waters  in  their  system  of  circulation.  The  chief  motive  power 
from  which  marine  currents  derive  their  velocity  has  been  ascribed 
to  heat ;  but  a  close  study  of  the  agents  concerned  has  suggested 
that  an  important — nay,  a  powerful  and  active  agency  in  the  sys- 
tem of  oceanic  circulation  is  derived  from  the  salts  of  the  sea  water, 
through  the  instrumentahty  of  the  winds,  of  marine  plants,  and 
animals.     These  give  the  ocean  great  dynamical  force. 

506.  Let  us,  for  the  sake  of  illustrating  and  explaining  this 
force,  suppose  the  sea  in  all  its  parts — in  its  depths  and  at  the  sur- 


186       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

face,  at  the  equator  and  about  the  poles — to  be  of  one  uniform 
temperature,  and  to  be  all  of  fresh  water ;  and,  moreover,  that 
there  be  neither  wind  to  disturb  its  surface,  nor  tides  nor  rains  to 
raise  the  level  in  this  part,  or  to  depress  it  in  that.  In  this  case, 
there  would  be  nothing  of  heat  to  disturb  its  equilibrium,  and 
there  would  be  no  motive  power  (§  490)  to  beget  currents,  or  to  set 
the  water  in  motion  by  reason  of  the  difference  of  level  or  of  spe- 
cific gravity  due  to  w^ater  at  different  densities  and  temperatures. 

507.  Now  let  us  suppose  the  winds,  for  the  first  time  since  the 
creation,  to  commence  to  blow  upon  this  quiescent  sea,  and  to 
ruffle  its  surface ;  they,  by  their  force,  would  create  partial  surface 
currents,  and  thus  agitating  the  waters,  as  they  do,  but  only  for  a 
little  way  below  the  surface,  w^ould  give  rise  to  a  feeble  and  partial 
aqueous  circulation  in  the  supposed  sea  of  fresh  water. 

508.  This,  then,  is  one  of  the  sources  whence  power  is  given 
to  the  system  of  oceanic  circulation ;  but,  though  a  feeble  one,  it 
is  one  which  exists  in  reality,  and,  therefore,  need  not  be  regarded 
as  hypothetical. 

509.  Let  us  next  call  in  evaporation  and  precipitation,  with 
heat  and  cold — more  powerful  agents.  Suppose  the  evaporation 
to  commence  from  this  imaginary  fresh-water  ocean,  and  to  go  on 
as  it  does  from  the  seas  as  they  are.  In  those  regions,  as  in  the 
trade- wind  regions,  where  evaporation  is  in  excess  of  precipitation 
(§  178),  the  general  level  of  this  supposed  sea  would  be  altered, 
and,  immediately,  as  much  water  as  is  carried  off  by  evaporation 
would  commence  to  flow  in  from  north  and  south  toward  the  trade- 
wind  or  evaporating  region,  to  restore  the  level. 

510.  On  the  other  hand,  the  winds  have  taken  this  vapor,  borne 
it  off  to  the  extra-tropical  regions,  and  precipitated  it,  we  will  sup- 
pose, where  precipitation  is  in  excess  of  evaporation.  Here  is 
another  alteration  of  sea  level  by  elevation  instead  of  by  depres- 
sion ;  and  hence  we  have  the  motive  power  for  a  surface  current 
fi:om  each  pole  toward  the  equator,  the  object  of  which  is  only  to 
supply  the  demand  for  evaporation  in  the  trade-wind  regions — 
demand  for  evaporation  being  taken  here  to  mean  the  difference 
between  evaporation  and  precipitation  for  any  part  of  the  sea. 

511.  Now  imagine  this  sea  of  uniform  temperature  (§  506)  to 


THE  SALTS  OF  THE  SEA.  I37 

be  suddenly  stricken  with  the  invisible  wand  of  heat  and  cold, 
and  its  waters  brought  to  the  various  temperatures  at  which  they 
at  this  instant  are  standing.  This  change  of  temperature  would 
make  a  change  of  specific  gravity  in  the  waters,  which  would  de- 
stroy tlie  equilibrium  of  the  whole  ocean,  upon  which  a  set  of  cur- 
rents w^ould  immediately  commence  to  flow,  namely,  a  current  of 
cold  and  heavy  water  to  the  warm,  and  a  current  of  warm  and 
lighter  to  the  cold. 

Tlie  motive  power  of  these  would  be  difference  of  specific  grav- 
ity due  to  difference  of  temperature  in  fresh  water. 

512.  We  have  now  traced  (§  507  and  511)  the  effect  of  two 
agents,  which,  in  a  sea  of  fresh  water,  would  tend  to  create  cur- 
rents, and  to  beget  a  system  of  aqueous  circulation ;  but  a  set  of 
currents,  and  a  system  of  circulation  which,  it  is  readily  perceived, 
would  be  quite  feeble  in  comparison  with  those  which  we  find  in 
the  salt  sea.  One  of  these  agents  would  be  employed  (§  509)  in 
restoring,  by  means  of  one  or  more  polar  currents,  the  water  that 
is  taken  from  one  part  of  the  ocean  by  evaporation,  and  deposited 
in  another  by  precipitation.  The  other  agent  would  be  employed 
in  restoring,  by  the  forces  due  difference  of  specific  gravity  (§  511), 
the  equilibrium,  which  has  been  disturbed  by  heating,  and  of 
course  expanding,  the  waters  of  the  torrid  zone  on  one  hand,  and 
by  cooling,  and  consequently  contracting,  those  of  the  frigid  zone 
on  the  other.  This  agency  would,  if  it  were  not  modified  by  oth- 
ers, find  expression  in  a  system  of  currents  and  counter  cuiTcnts, 
or  rather  in  a  set  of  surface  currents  of  warm  and  light  water, 
from  the  equator  toward  the  poles,  and  in  another  set  of  under 
currents  of  cooler,  dense,  and  heavy  water  from  the  poles  toward 
the  equator. 

513.  Such,  keeping  out  of  view  the  influence  of  the  winds, 
which  we  may  suppose  would  be  the  same  whether  the  sea  were 
salt  or  fresh,  would  be  the  system  of  oceanic  circulation  were  the 
sea  all  of  fresh  water.  But  fresh  water,  in  cooling,  begins  to  ex- 
pand near  the  temperature  of  40°,  and  expands  more  and  more 
till  it  reaches  the  freezing  point,  and  ceases  to  be  fluid.  This  law 
of  expansion  by  cooling  would  impart  a  peculiar  feature  to  the 
system  of  oceanic  circulation  were  the  waters  all  fresh,  which  it 


188  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

is  not  necessary  to  notice  farther  than  to  say  it  can  not  exist  in 
seas  of  salt  water,  for  salt  water  (§31)  contracts  as  its  tempera- 
ture is  lowered  to  its  freezing  point.  Hence,  in  consequence  of 
its  salts,  changes  of  temperature  derive  increased  power  to  disturb 
the  equilibrium  of  the  ocean. 

514.  If  this  train  of  reasoning  be  good,  we  may  infer  that,  in  a 
system  of  oceanic  circulation,  the  dynamical  force  to  be  derived 
from  difference  of  temperature,  where  the  waters  are  all  fresh, 
would  be  quite  feeble ;  and  that,  were  the  sea  not  salt,  we  should 
probably  have  no  such  current  in  it  as  the  Gulf  Stream. 

515.  So  far  we  have  been  reasoning  hypothetically,  to  show 
what  would  be  the  chief  agents,  exclusive  of  the  winds,  in  disturb- 
ing the  equilibrium  of  the  ocean,  were  its  waters  fresh  and  not  salt. 
And  whatever  disturbs  equilibrium  there  may  be  regarded  as  th^ 
jprimiiin  mobile  in  any  system  of  marine  currents. 

516.  Let  us  now  proceed  another  step  in  the  process  of  ex- 
plaining and  illustrating  the  effect  of  the  salts  of  the  sea  in  the  sys- 
tem of  oceanic  circulation.  To  this  end,  let  us  suppose  the  im- 
aginary ocean  of  fresh  water  suddenly  to  become  that  which  we 
have,  namely,  an  ocean  of  salt  water,  which  contracts  as  its  tem- 
perature is  lowered  (§  513)  till  it  reaches  28°  or  thereabout. 

517.  Let  evaporation  now  commence  in  the  trade-wind  region, 
as  it  was  supposed  to  do  (§  509)  in  the  case  of  the  fresh-water 
seas,  and  as  it  actually  goes  on  in  nature — and  what  takes  place  ? 
Why,  a  lowering  of  the  sea  level,  as  before.  But  as  the  vapor  of 
salt  water  is  fresh,  or  nearly  so,  fresh  water  only  is  taken  up  from 
the  ocean ;  that  which  remains  behind  is  therefore  more  salt. 
Thus,  while  the  level  is  lowered  in  the  salt  sea,  the  equilibrium  is 
destroyed  because  of  the  saltness  of  the  water ;  for  the  water  that 
remains  after  the  evaporation  takes  place  is,  on  account  of  the 
solid  matter  held  in  solution,  specifically  heavier  than  it  was  be- 
fore any  portion  of  it  was  converted  into  vapor. 

518.  The  vapor  is  taken  from  the  surface  water ;  the  surface 
water  thereby  becomes  more  salt,  and,  under  certain  conditions, 
heavier ;  when  it  becomes  heavier,  it  sinks ;  and  hence  we  have, 
due  to  the  salts  of  the  sea,  a  vertical  circulation,  namely,  a  descent 
of  heavier — because  Salter  and  cooler — water  from  the  surface,  and 


THE  SALTS  OF  THE  SEA.  Xg9 

an  ascent  of  water  that  is  lighter — "because  it  is  not  so  salt — from 
the  depths  below. 

519.  This  vapor,  then,  which  is  taken  np  from  the  evaporating 
regions  (§  179),  is  carried  by  the  winds  through  their  channels  of 
circulation,  and  poured  back  into  the  ocean  where  the  regions  of 
precipitation  are  ;  and  by  the  regions  of  precipitation  I  mean  those 
parts  of  the  ocean,  as  in  the  polar  basins,  where  the  ocean  receives 
more  fresh  water  in  the  shape  of  rain,  snow,  etc.,  than  it  returns 
to  the  atmosphere  in  the  shape  of  vapor. 

520.  In  the  precipitating  regions,  therefore,  the  level  is  de- 
stroyed, as  before  explained,  by  elevation  ;  and  in  the  evaporating 
regions,  by  depression  ;  which,  as  already  stated  (§  509),  gives  rise 
to  a  system  of  surface  currents,  moved  by  gravity  alone,  from  the 
poles  toward  the  equator. 

521.  But  we  are  now  considering  the  effects  of  evaporation  and 
precipitation  in  giving  impulse  to  the  circulation  of  the  ocean  where 
its  waters  are  salt.  The  fresh  water  that  has  been  taken  from  the 
evaporating  regions  is  deposited  upon  those  of  precipitation,  which, 
for  illustration  merely,  we  will  locate  in  the  north  Polar  basin. 
Among  the  sources  of  supply  of  fresh  water  for  this  basin,  we 
must  include  not  only  the  precipitation  which  takes  place  over 
the  basin  itself,  but  also  the  amount  of  fresh  water  discharged  into 
it  by  the  rivers  of  the  great  hydrographical  basins  of  Arctic  Eu- 
rope, Asia,  and  America. 

522.  This  fresh  water,  being  emptied  into  the  Polar  Sea  and 
agitated  by  the  winds,  becomes  mixed  with  the  salt ;  but  as  the 
agitation  of  the  sea  by  the  winds  is  supposed  to  extend  to  no  great 
depth  (§  507),  it  is  only  the  upper  layer  of  salt  w^ater,  and  that  to 
a  moderate  depth,  which  becomes  mixed  with  the  fresh.  The 
specific  gravity  of  this  upper  layer,  therefore,  is  diminished  just  as 
much  as  the  specific  gravity  of  the  sea  water  in  the  evaporating 
regions  was  increased.  And  thus  we  have  a  surface  current  of 
saltish  water  from  the  poles  toward  the  equator,  and  an  under 
current  of  water  Salter  and  heavier  from  the  equator  to  the  poles. 
This  under  current  supplies,  in  a  great  measure,  the  salt  which  the 
upper  current,  freighted  with  fresh  water  from  the  clouds  and  riv- 
ers, carries  back. 


190       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

523.  Thus  it  is  to  the  salts  of  the  sea  that  we  owe  that  feature 
in  the  system  of  oceanic  circulation  which  causes  an  under  cur- 
rent to  flow  from  the  Mediterranean  into  the  Atlantic  (§  425),  and 
another  (§  413)  from  the  Eed  Sea  into  the  Indian  Ocean.  And 
it  is  evident,  since  neither  of  these  seas  is  salting  up,  that  just  as 
much,  or  nearly  just  as  much  salt  as  the  under  cuiTcnt  brings  out, 
just  so  much  the  upper  currents  carry  in. 

524.  We  now  begin  to  perceive  what  a  powerful  impulse  is 
derived  from  the  salts  of  the  sea  in  giving  effective  and  active  cir- 
culation to  its  waters. 

525.  Hence  we  infer  that  the  currents  of  the  sea,  by  reason  of 
its  saltness,  attain  their  maximum  of  volume  and  velocity.  Hence, 
too,  we  infer  that  the  transportation  of  warm  water  from  the  equa- 
tor toward  the  frozen  regions  of  the  poles,  and  of  cold  water  from 
the  frigid  toward  the  torrid  zone,  is  facilitated  ;  and  consequently 
here,  in  the  saltness  of  the  sea,  have  we  not  an  agent  by  which 
climates  are  mitigated — by  which  they  are  softened  and  rendered 
much  more  salubrious  than  it  would  be  possible  for  them  to  be 
were  the  waters  of  the  ocean  deprived  of  their  property  of  saltness  ? 

526.  This  property  of  saltness  imparts  to  the  waters  of  the 
ocean  another  peculiarity,  by  which  the  sea  is  still  better  adapted 
for  the  regulation  of  climates,  and  it  is  this  :  by  evaporating  fresh 
water  from  the  salt  in  the  tropics,  the  surface  water  becomes 
heavier  than  the  average  of  sea  water  (§  181).  This  heavy  water 
is  also  warm  water ;  it  sinks,  and  being  a  good  retainer,  but  a  bad 
conductor  of  heat,  this  warm  water  is  employed  in  transporting 
through  under  currents  heat  for  the  mitigation  of  climates  in  far- 
distant  regions.  Now  this  also  is  a  property  which  a  sea  of  fresh 
water  could  not  have.  Let  the  winds  take  up  their  vapor  from  a 
sheet  of  fresh  water,  and  that  at  the  bottom  is  not  disturbed,  for 
there  is  no  change  in  the  specific  gravity  of  that  at  the  surface  by 
which  that  at  the  bottom  may  be  brought  to  the  top  ;  but  let 
evaporation  go  on,  though  never  so  gently,  from  salt  water,  and 
the  specific  gravity  of  that  at  the  top  will  soon  be  so  changed  as 
to  bring  that  from  the  very  lowest  depths  of  the  sea  to  the  top. 

527.  If  all  the  salts  of  the  sea  were  precipitated  and  spread 
out  equally  over  the  northern  half  of  this  continent,  it  would,  it 


THE  SALTS  OF  THE  SEA.  291 

lias  been  computed,  cover  tlie  ground  one  mile  deep.  What  force 
could  move  such  a  mass  of  matter  on  the  dry  land?  Yet  the 
machinery  of  the  ocean,  of  which  it  forms  a  part,  is  so  wisely, 
marvelously,  and  wonderfully  compensated,  that  the  most  gentle 
breeze  that  plays  on  its  bosom,  the  tiniest  insect  that  secrets  solid 
matter  for  its  sea-shell,  is  capable  of  putting  it  instantly  in  mo- 
tion. Still,  when  solidified  and  placed  in  a  heap,  all  the  mechan- 
ical contrivances  of  man,  aided  by  the  tremendous  forces  of  all 
the  steam  and  water  power  of  the  world,  could  not  move  even  so 
much  as  an  inch  in  centuries  of  time  this  matter  which  tlie  sun- 
beam, the  zephyr  and  the  infusorial  insect  keep  in  perpetual  mo- 
tion and  activity. 

528.  If  these  inferences  as  to  the  influence  of  the  salts  upon 
the  currents  of  the  sea  be  correct,  the  same  cause  which  produces 
an  under  current  from  the  ]\Iediterranean,  and  an  under  current 
from  the  E-ed  Sea  into  the  ocean,  should  produce  an  under  cur- 
rent from  the  ocean  into  the  north  Polar  basin.  In  each  case,  the 
hypothesis  with  regard  to  the  part  performed  by  the  salt,  in  giv- 
ing vigor  to  the  system  of  oceanic  circulation,  requires  that,  coun- 
ter to  the  surface  current  of  water  with  less  salt,  there  should  be 
an  under  current  ot  water  with  more  salt  in  it. 

529.  That  such  is  the  case  with  regard  both  to  the  Mediterra- 
nean and  the  Eed  Sea  has  been  amply  shown  in  other  parts  of  this 
work  (§  523),  and  abundantly  proved  by  other  observers. 

530.  That  there  is  a  constant  current  setting  out  of  the  Arctic 
Ocean  through  Davis's  and  other  straits  thereabout,  which  con- 
nect it  with  the  Atlantic  Ocean,  is  generally  admitted.  Lieuten- 
ant De  Haven,  United  States  Navy,  when  in  command  of  the 
American  expedition  in  search  of  Sir  John  Franklin,  was  frozen 
up  with  his  vessels  in  mid-channel  near  Wellington  Straits  ;  and 
during  the  nine  months  that  he  was  so  frozen,  his  vessels,  like 
H.  B.  Si.  ship  Eesolute  (§  487),  each  holding  its  place  in  the  ice, 
were  drifted  with  it  bodily  for  more  than  a  thousand  miles  toward 
the  south. 

531.  The  ice  in  which  they  were  bound  was  of  sea  water,  and 
the  currents  by  which  they  were  drifted  were  of  sea  water — only, 
it  may  be  supposed,  the  latter  were  not  quite  so  salt  as  the  sea 


192       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

water  generally  is.  The  same  phenomenon  is  repeated  in  the  Bal- 
tic, where  (§  423)  an  under  current  of  salt  water  runs  in,  and  an 
upper  current  of  brackish  water  (§  37)  runs  out. 

532.  Then,  since  there  is  salt  always  flowing  out  of  the  north 
Polar  basin,  we  infer  that  there  must  be  salt  always  flowing  into 
it,  else  it  would  either  become  fresh,  or  the  whole  Atlantic  Ocean 
would  be  finally  silted  up  with  salt. 

533.  It  might  be  supposed,  were  there  no  evidence  to  the  con- 
trary, that  this  salt  was  supplied  to  the  Polar  seas  from  the  At- 
lantic around  North  Cape,  and  from  the  Pacific  through  Behring's 
Straits,  and  through  no  other  channels. 

534.  But,  fortunately,  Arctic  voyagers,  who  have  cruised  in  the 
direction  of  Davis's  Straits,  have  afforded  us,  by  their  observations 
(§  478),  proof  positive  as  to  the  fact  of  this  other  source  for  sup- 
plying the  Polar  seas  with  salt.  They  tell  us  of  an  under  current 
setting  from  the  Atlantic  toward  the  Polar  basin.  They  describe 
huge  icebergs,  with  tops  high  up  in  the  air,  and  of  course  the 
bases  of  which  extend  far  down  into  the  depths  of  the  ocean,  rip- 
ping and  tearing  their  way  with  terrific  force  and  awful  violence 
through  the  surface  ice  or  against  a  surface  current,  on  their  way 
into  the  Polar  basin. 

535.  Passed  Midshipman  S.  P.  Griffin,  who  commanded  the 
brig  Rescue  in  the  American  searching  expedition  after  Sir  John 
Franklin,  informs  me  that,  on  one  occasion,  the  two  vessels  were 
endeavoring,  when  in  Baffin's  Bay,  to  warp  up  to  the  northward 
against  a  strong  surface  current,  which  of  course  was  setting  to 
the  south ;  and  that  while  so  engaged,  an  iceberg,  with  its  top 
many  feet  above  the  water,  came  "  drifting  up"  from  the  south, 
and  passed  by  them  "like  a  shot."  Although  they  were  stem- 
ming a  surface  current  against  both  the  berg  and  themselves,  such 
was  the  force  and  velocity  of  the  under  current,  that  it  carried  the 
berg  to  the  northward  faster  than  the  crew  could  warp  the  vessel 
against  a  surface  but  counter  current. 

536.  Captain  Duncan,  master  of  the  English  whale-ship  Dun- 
dee, says,  at  page  76  of  his  interesting  little  narrative  :* 

*  Arctic  Regions  ;  Voyage  to  Davis's  Strait,  by  Dorea  Duncan,  Master  of  the  Ship 
Dundee,  1826,  1827. 


THE  SALTS  OF  THE  SEA.  193 

^'December  \^th  (1826).  It  was  awful  to  behold  the  immense 
icel)er2;s  working  their  way  to  the  northeast  from  lis,  and  not  one 
drop  of  water  to  be  seen ;  they  were  working  themselves  right 
through  the  middle  of  the  ice." 

And  again,  at  page  92,  etc. : 

'■'-Fehruarij  23d.  Latitude  68°  37^  north,  longitude  about  63° 
west. 

"  The  dreadful  apprehensions  that  assailed  us  yesterday,  by 
the  near  approach  of  the  iceberg,  were  this  day  most  awfully  ver- 
ified. About  three  P.M.  the  iceberg  came  in  contact  Yfith  our 
floe,  and  in  less  than  one  minute -it  broke  the  ice  ;  we  were  frozen 
in  quite  close  to  the  shore ;  the  floe  was  shivered  to  pieces  for 
several  miles,  causing  an  explosion  like  an  earthquake,  or  one 
hundred  pieces  of  heavy  ordnance  fired  at  the  same  moment. 
The  iceberg,  with  awful  but  majestic  grandeur  (in  height  and  di- 
mensions resembling  a  vast  mountain),  came  almost  up  to  our 
stern,  and  every  one  expected  it  would  have  run  over  the 
ship 

"The  iceberg,  as  before  observed,  came  up  very  near  to  the 
stern  of  our  ship ;  the  intermediate  space  between  the  berg  and 
the  vessel  was  filled  with  heavy  masses  of  ice,  which,  though  they 
had  been  previously  broken  by  the  immense  weight  of  the  berg, 
were  again  formed  into  a  compact  body  by  its  pressure.  The 
berg  was  drifting  at  the  rate  of  about  four  knots,  and  by  its  force 
on  the  mass  of  ice,  was  pushing  the  ship  before  it,  as  it  appeared, 
to  inevitable  destruction." 

"7^^.  24t/i.  The  iceberg  still  in  sight,  but  driving  away  fast  to 
the  northeast." 

^''Feh.  26th.  The  iceberg  that  so  lately  threatened  our  destruc- 
tion had  driven  completely  out  of  sight  to  the  northeast  from  us." 

537.  Now,  then,  whence,  unless  from  the  difference  of  specific 
gravity  due  sea  water  of  different  degrees  of  saltness  and  temper- 
ature, can  we  derive  a  motive  power  with  force  sufficient  to  give 
such  tremiendous  masses  of  ice  such  a  velocity  ? 

538.  What  is  the  temperature  of  this  under  current  ?  Be  that 
what  it  may,  it  is  probably  above  the  freezing  point  of  sea  water. 
Suppose  it  to  be  at  32°.     (Break  through  the  ice  in  the  northern 


194       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

seas,  and  the  temperature  of  the  surface  water  is  always  28°.  At 
least  Lieutenant  De  Haven  so  found  it  in  his  long  imprisonment, 
and  it  may  be  supposed  that,  as  it  was  with  him,  so  it  generally 
is).  Assuming,  then,  the  water  of  the  surface  current  which  runs 
out  with  the  ice  to  be  all  at  28°,  we  observe  that  it  is  not  unrea- 
sonable to  suppose  that  the  water  of  the  under  current,  inasmuch 
as  it  comes  from  the  south,  and  therefore  from  warmer  latitudes, 
is  probably  not  so  cold ;  and  if  it  be  not  so  cold,  its  temperature, 
before  it  comes  out  again,  must  be  reduced  to  28°,  or  whatever  be 
the  average  temperature  of  the  outer  but  surface  currelit.  Dr. 
Kane  found  the  temperature  of  the  open  sea  in  the  Arctic  Ocean 
(§  486)  as  high  as  36°.  Can  water  flow  in  the  depths  below  from 
the  mild  climate  of  the  temperate  zones  to  the  severe  climates  of 
the  frigid  zone  without  falling  below  36°  ?  To  what,  in  the  depths 
of  the  sea,  can  a  warm  current  of  large  volume  impart  its  heat  ? 

539.  Moreover,  if  it  be  true,  as  some  philosophers  have  suggest- 
ed, that  there  is  in  the  depths  of  the  ocean  a  floor  or  plane  from  the 
equator  to  the  poles  along  which  the  water  is  of  the  same  temper- 
ature all  the  way,  then  the  question  may  be  asked.  Should  we  not 
have  in  the  depths  of  the  ocean  a  sort  of  isothermal  floor,  as  it 
were,  on  the  upper  side  of  which  all  the  changes  of  temperature 
are  due  to  agents  acting  from  above,  and  on  the  lower  side  of 
which,  the  changes,  if  any,  are  due  to  agents  acting  from  below  ? 

540.  This  under  Polar  current  water,  then,  as  it  rises  to  the 
top,  and  is  brought  to  the  surface  by  the  agitation  of  the  sea  in 
the  Arctic  regions,  gives  out  its  surplus  heat  and  warms  the  at- 
mosphere there  till  the  temperature  of  this  warm  under  current 
water  is  lowered  to  the  requisite  degree  for  going  out  on  the  sur- 
face.    Hence  the  water-sky  of  those  regions. 

541.  And  the  heat  that  it  loses  in  falling  from  its  normal  tem- 
perature, be  that  what  it  may,  till  it  reaches  the  temperature  of 
28°,  is  so  much  caloric  set  free  in  the  Polar  regions,  to  temper  the 
air  and  mitigate  the  climate  there.  Now  is  not  this  one  of  those 
modifications  of  climate  which  may  be  fairly  traced  back  to  the  ef- 
fect of  the  saltness  of  the  sea  in  giving  energy  to  its  circulation  ? 

542.  Moreover,  if  there  be  a  deep  sea  in  the  Polar  basin,  which 
serves  as  a  receptacle  for  the  waters  brought  into  it  by  this  under 


THE  SALTS  OF  THE  SEA.  195 

current,  which,  because  it  comes  from  toward  the  equatorial  re- 
gions, comes  from  a  milder  climate,  and  is  therefore  warmer,  we 
can  easily  imagine  whj  there  might  be  an  open  sea  in  the  Polar 
regions — why  Lieutenant  De  Haven,  in  his  instructions  (§  482), 
was  directed  to  look  for  it ;  and  why  both  he  and  Captain  Penny, 
of  one  of  the  English  searching  vessels,  and  afterward  Dr.  Kane, 
found  it  there. 

543.  And  in  accounting  for  this  polynia,  we  see  that  its  exist- 
ence is  not  only  consistent  with  the  hypothesis  with  which  we  set 
out,  touching  a  perfect  system  of  oceanic  circulation,  but  that  it 
may  be  ascribed,  in  a  great  degree  at  least,  if  not  wholly,  to  the 
effect  produced  by  the  salts  of  the  sea  upon  the  mobility  and  cir- 
culation of  its  waters. 

544.  Here,  then,  is  an  office  which  the  sea  performs  in  the  econ- 
omy of  the  universe  by  virtue  of  its  saltness,  and  which  it  could 
not  perform  were  its  waters  altogether  fresh,  ilnd  thus  philoso- 
phers have  a  clew  placed  in  their  hands  which  will  probably  guide 
them  to  one  of  the  many  hidden  reasons  that  are  embraced  in  the 
true  answer  to  the  question,  "Why  is  the  sea  salt?" 

545.  Sea  Shells. — We  find  in  sea  water  other  matter  besides 
common  salt.  Lime  is  dissolved  by  the  rains  and  the  rivers,  and 
emptied  in  vast  quantities  into  the  ocean.  Out  of  it,  coral  islands 
and  coral  reefs  of  great  extent  —  marl-beds,  shell-banks,  and  in- 
fusorial deposits  of  enormous  magnitude  have  been  constructed  by 
the  inhabitants  of  the  deep.  These  creatures  are  endowed  with 
the  power  of  secreting,  apparently  for  their  own  purposes  only, 
solid  matter,  which  the  waters  of  the  sea  hold  in  solution.  But 
this  power  was  given  to  them  that  they  also  might  fulfill  the  part 
assigned  them  in  the  economy  of  the  universe.  For  to  them, 
probably,  has  been  allotted  the  important  office  of  assisting  in 
giving  circulation  to  the  ocean,  of  helping  to  regulate  the  cli- 
mates of  the  earth,  and  of  preserving  the  purity  of  the  sea. 

546.  The  better  to  comprehend  how  such  creatures  may  influ- 
ence currents  and  climates,  let  us  suppose  the  ocean  to  be  per- 
fectly at  rest — that  throughout,  it  is  in  a  state  of  complete  equi- 
librium— that,  with  the  exception  of  those  tenants  of  the  deep 
which  have  the  power  of  extracting  from  it  the  solid  matter  held 


196       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

in  solution,  there  is  no  agent  in  nature  capable  of  disturbing  that 
equilibrium — and  that  all  these  fish,  etc.,  have  suspended  their  se- 
cretions, in  order  that  this  state  of  a  perfect  aqueous  equilibrium 
and  repose  throughout  the  sea  might  be  attained. 

547.  In  this  state  of  things — the  <  waters  of  the  sea  being  in 
perfect  equilibrium — a  single  mollusk  or  coralline,  we  will  sup- 
pose, commences  his  secretions,  and  abstracts  from  the  sea  water 
(§  498)  soHd  matter  for  his  cell.  In  that  act,  this  animal  has  de- 
stroyed the  equilibrium  of  the  whole  ocean,  for  the  specific  gravity 
of  that  portion  of  water  from  which  this  solid  matter  has  been  ab- 
stracted, is  altered.  Having  lost  a  portion  of  its  solid  contents,  it 
has  become  specifically  lighter  than  it  was  before ;  it  must,  there- 
fore, give  place  to  the  pressure  which  the  heavier  water  exerts  to 
push  it  aside  and  to  occupy  its  place,  and  it  must  consequently 
travel  about  and  mingle  with  the  waters  of  the  other  parts  of  the 
ocean  until  its  proportion  of  solid  matter  is  returned  to  it,  and 
until  it  attains  the  exact  degree  of  specific  gravity  due  sea  water 
generally. 

548.  How  much  solid  matter  does  the  whole  host  of  marine 
plants  and  animals  abstract  from  sea  water  daily  ?  Is  it  a  thou- 
sand pounds,  or  a  thousand  millions  of  tons  ?  No  one  can  say. 
But,  whatever  be  its  weight,  it  is  so  much  of  the  power  of  gravity 
applied  to  the  dynamical  forces  of  the  ocean.  And  this  power  is 
derived  from  the  salts  of  the  sea,  through  the  agency  of  sea-shells 
and  other  marine  animals,  that  of  themselves  scarcely  possess  the 
power  of  locomotion.  Yet  they  have  power  to  put  the  whole  sea 
in  motion,  from  the  equator  to  the  poles,  and  from  top  to  bottom. 

549.  Those  powerful  and  strange  equatorial  currents  (§  458), 
which  navigators  tell  us  they  encounter  in  the  Pacific  Ocean,  to 
what  are  they  due?  Coming  from  sources  unknown,  they  are 
lost  in  the  midst  of  the  ocean.  They  are  due,  no  doubt,  to  some 
extent,  to  the  efiects  of  precipitation  and  evaporation,  and  the 
change  of  heat  produced  thereby.  But  we  have  yet  to  inquire 
how  far  may  they  be  due  to  the  derangement  of  equilibrium  aris- 
ing from  the  change  of  specific  gravity  caused  by  the  secretions 
of  the  myriads  of  marine  animals  that  are  continually  at  work  in 
those  parts  of  the  ocean.     These  abstract  from  sea  water  solid 


THE  SALTS  OF  THE  SEA.  I97 

matter  enough  to  build  continents  of.  And,  also,  we  have  to  in- 
quire as  to  the  extent  to  which  equilibrium  in  the  sea  is  disturbed 
by  the  salts  which  evaporation  leaves  behind. 

550.  Thus,  when  we  consider  the  salts  of  the  sea  in  one  point 
of  view,  we  see  the  winds  and  the  marine  animals  operating  upon 
the  waters,  and,  in  certain  parts  of  the  ocean,  deriving  from  the 
solid  contents  of  the  same  those  very  principles  of  antagonistic 
forces  which  hold  the  earth  in  its  orbit,  and  preserve  the  harmo- 
nies of  the  universe. 

551.  In  another  point  of  view,  we  see  the  sea-breeze  and  the 
sea-shell,  in  performing  their  appointed  offices,  acting  so  as  to  give 
rise  to  a  reciprocating  motion  in  the  waters ;  and  thus  they  impart 
to  the  ocean  dynamical  forces  also  for  its  circulation. 

552.  The  sea-breeze  plays  upon  the  surface ;  it  converts  only 
fresh  water  into  vapor,  and  leaves  the  solid  matter  behind.  The 
surface  water  thus  becomes  specifically  heavier,  and  sinks.  On 
the  other  hand,  the  little  marine  architect  below,  as  he  works 
upon  his  coral  edifice  at  the  bottom,  abstracts  from  the  water 
there  a  portion  of  its  solid  contents ;  it  therefore  becomes  specif- 
ically lighter,  and  up  it  goes,  ascending  to  the  top  with  increased 
velocity,  to  take  the  place  of  the  descending  column,  which,  by 
the  action  of  the  winds,  has  been  sent  down  loaded  with  fresh 
food  and  materials  for  the  busy  little  mason  in  the  depths  below. 

552.  Seeing,  then,  that  the  inhabitants  of  the  sea,  with  their 
powers  of  secretion,  are  competent  to  exercise  at  least  some  degree 
of  influence  in  disturbing  equilibrium,  are  not  these  creatures  en- 
titled to  be  regarded  as  agents  which  have  their  offices  to  perform 
in  the  system  of  oceanic  circulation,  and  do  not  they  belong  to  its 
physical  geography  ?  It  is  immaterial  how  great  or'  how  small 
that  influence  may  be  supposed  to  be ;  for,  be  it  great  or  small, 
we  may  rest  assured  it  is  not  a  chance  influence,  but  it  is  an  in- 
fluence exercised — if  exercised  at  all — by  design,  and  according  to 
the  commandment  of  Him  whose  "  voice  the  winds  and  the  sea 
obey."     Thus  God  speaks  through  sea-shells  to  the  ocean. 

553.  It  may  therefore  be  supposed  that  the  arrangements  in  the 
economy  of  nature  are  such  as  to  require  that  the  various  kinds 
of  marine  animals,  whose,  secretions  are  calculated  to  alter  the 


198  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

specific  gravity  of  sea  water,  to  destroy  its  equilibrium,  to  Ibeget 
currents  in  tlie  ocean,  and  to  control  its  circulation,  should  be  dis- 
tributed according  to  order. 

554.  Upon  tliis  supposition — the  like  of  wliicli  nature  warrants 
throughout  her  whole  domain — we  may  conceive  how  the  marine 
animals  of  which  we  have  been  speaking  may  impress  other  fea- 
tures upon  the  physical  relations  of  the  sea  by  assisting  also  to 
regulate  climates,  and  to  adjust  the  temperature  of  certain  lati- 
tudes. For  instance,  let  us  suppose  the  waters  in  a  certain  part 
of  the  torrid  zone  to  be  90°,  but,  by  reason  of  the  fresh  water 
which  has  been  taken  from  them  in  a  state  of  vapor,  and  conse- 
quently by  reason  of  the  proportionate  increase  of  salts,  these  wa- 
ters are  heavier  than  waters  that  may  be  cooler,  but  not  so  salt 
(§  35).  This  being  the  case,  the  tendency  would  be  for  this  warm, 
but  salt  and  heavy  water,  to  flow  off  as  an  under  current  toward 
the  Polar  or  some  other  regions  of  lighter  water. 

555.  Now  if  the  sea  were  not  salt,  there  would  be  no  coral  isl- 
ands to  beautify  its  landscape  and  give  variety  to  its  features ; 
sea-shells  and  marine  insects  could  not  operate  upon  the  specific 
gravity  of  its  waters,  nor  give  diversity  to  its  climates ;  neither 
could  evaporation  give  dynamical  force  to  its  circulation,  and  its 
waters,  ceasing  to  contract  as  their  temperature  falls  below  39°, 
would  give  but  little  impulse  to  its  currents,  and  thus  its  circula- 
tion would  be  torpid,  and  its  bosom  lack  animation, 

556.  This  under  current  may  be  freighted  with  heat  to  temper 
some  hyperborean  region  or  to  soften  some  extra-tropical  climate, 
for  we  know  that  such  is  among  the  efiects  of  marine  currents. 
At  starting,  it  might  have  been,  if  you  please,  so  loaded  with  solid 
matter,  that,  though  its  temperature  were  90°,  yet,  by  reason  of 
the  quantity  of  such  matter  held  in  solution,  its  specific  gravity 
might  have  been  greater  even  than  that  of  extra-tropical  sea  water 
generally  at  28°. 

557.  Notwithstanding  this,  it  may  be  brought  into  contact,  by 
the  way,  with  those  kinds  and  quantities  of  marine  organisms  that 
shall  abstract  solid  matter  enough  to  reduce  its  specific  gravity, 
and,  instead  of  leaving  it  greater  than  common  sea  water  at  28°, 
make  it  less  than  common  sea  water  at  39° ;  consequently,  in 


THE  SALTS  OF  THE  SEA.  I99 

such  a  case,  tliis  warm  sea  water,  when  it  comes  to  the  cold  lati- 
tudes, would  be  brought  to  the  surface  through  the  instrumental- 
ity of  shell-fish,  and  various  other  tribes  that  dwell  far  down  in 
the  depths  of  the  ocean.  Thus  we  perceive  that  these  creatures, 
though  they  are  regarded  as  being  so  low  in  the  scale  of  creation, 
may  nevertheless  be  regarded  as  agents  of  much  importance  in 
the  terrestrial  economy ;  for  we  now  comprehend  how  they  are 
capable  of  spreading  over  certain  parts  of  the  ocean  those  benign 
mantles  of  warmth  which  temper  the  winds,  and  modify,  more  or 
less,  all  the  marine  climates  of  the  earth. 

558.  The  makers  of  nice  astronomical  instruments,  when  they 
have  put  the  different  parts  of  their  machinery  together,  and  set 
it  to  work,  find,  as  in  the  chronometer,  for  instance,  that  it  is  sub- 
ject in  its  performance  to  many  irregularities  and  imperfections ; 
that  in  one  state  of  things  there  is  expansion,  and  in  another  state 
contraction  among  cogs,  springs,  and  wheels,  with  an  increase  or 
diminution  of  rate.  This  defect  the  makers  have  sought  to  over- 
come ;  and,  with  a  beautiful  display  of  ingenuity,  they  have  at- 
tached to  the  works  of  the  instrument  a  contrivance  which  has 
had  the  effect  of  correcting  these  irregularities,  by  counteracting 
the  tendency  of  the  instrument  to  change  its  performance  with  the 
changing  influences  of  temperature. 

559.  This  contrivance  is  called  a  compensation  ;  and  a  chro- 
nometer  that  is  well  regulated  and  properly  compensated  will  per- 
form its  office  with  certainty,  and  preserve  its  rate  under  all  the 
vicissitudes  of  heat  and  cold  to  which  it  may  be  exposed. 

560.  In  the  clock-work  of  the  ocean  and  the  machinery  of  the 
universe,  order  and  regularity  are  maintained  by  a  system  of  com- 
pensations. A  celestial  body,  as  it  revolves  around  its  sun,  flies 
off  under  the  influence  of  centrifugal  force ;  but  immediately  the 
forces  of  compensation  begin  to  act ;  the  planet  is  brought  back 
to  its  elliptical  path,  and  held  in  the  orbit  for  which  its  mass,  its 
motions,  and  its  distance  were  adjusted.  Its  compensation  is 
perfect. 

561.  So,  too,  with  the  salts  and  the  shells  of  the  sea  in  the  ma- 
chinery of  the  ocean ;  from  them  are  derived  principles  of  com- 
pensation the  most  perfect ;  through  their  agency  the  undue  effects 


200       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

of  heat  and  cold,  of  storm  and  rain,  in  disturbing  the  equilibrium, 
and  producing  thereby  currents  in  the  sea,  are  compensated,  reg- 
ulated, and  controlled. 

562.  The  dews,  the  rains,  and  the  rivers  are  continually  dis- 
solving certain  minerals  of  the  earth,  and  carrying  them  off  to  the 
sea.  This  is  an  accumulative  process ;  and  if  it  were  not  com- 
jpensated^  the  sea  would  finally  become,  as  the  Dead  Sea  is,  satu- 
rated with  salt,  and  therefore  unsuitable  for  the  habitation  of 
many  fish  of  the  sea. 

563.  The  sea-shells  and  marine  insects  afford  the  required  com- 
joensation.  They  are  the  conservators  of  the  ocean.  As  the 
salts  are  emptied  into  the  sea,  these  creatures  secrete  them  again 
and  pile  them  up  in  solid  masses,  to  serve  as  the  bases  of  islands 
and  continents,  to  be  in  the  process  of  ages  upheaved  into  dry 
land,  and  then  again  dissolved  by  the  dews  and  rains,  and  washed 
by  the  rivers  away  into  the  sea. 

564.  The  question  as  to  whence  the  salts  of  the  sea  were  orig- 
inally derived,  of  course  has  not  escaped  the  attention  of  philoso- 
phers. 

bQA.  I  once  thought  with  Darwin  and  those  other  philosophers 
who  hold  that  the  sea  derived  its  salts  originally  from  the  wash- 
ings of  the  rains  and  rivers.  I  now  question  that  opinion ;  for, 
in  the  course  of  the  researches  connected  with  the  "  Wind  and 
Current  Charts,"  I  have  found  evidence,  from  the  sea  and  in  the 
Bible,  which  seems  to  cast  doubt  upon  it.  The  account  given  in 
the  first  chapter  of  Genesis,  and  that  contained  in  the  hieroglyph- 
ics which  are  traced  by  the  hand  of  Nature  on  the  geological  col- 
umn as  to  the  order  of  creation,  are  marvelously  accordant.  The 
Christian  man  of  science  regards  them  both  as  true  ;  and  he  nev- 
er overlooks  the  fact  that,  wliile  they  differ  in  the  mode  and  man- 
ner as  well  as  in  the  things  they  teach,  yet  they  never  conflict ; 
and  they  contain  no  evidence  going  to  show  that  the  sea  was  ever 
fresh ;  on  the  contrary,  they  both  afford  circumstantial  evidence 
sufficient  for  the  belief  that  the  sea  was  salt  as  far  back  as  the 
morning  of  creation,  or  at  least  as  the  evening  and  the  morning 
of  the  day  when  the  dry  land  appeared. 

6Q6.  That  the  rains  and  the  rivers  do  dissolve  salts  of  various 


THE  SALTS  OF  THE  SEA.  201 

kinds  from  the  rocks  and  soil,  and  empty  them  into  the  sea,  there 
is  no  doubt.  These  salts  can  not  be  evaporated,  we  know  ;  and 
we  also  know  tliat  many  of  the  lakes,  as  the  Dead  Sea,  which  re- 
ceive rivers  and  have  no  outlet,  are  salt.  Hence  the  inference  by 
some  philosophers  (§  502)  that  these  inland  water-basins  received 
their  salts  from  the  washings  of  the  soil ;  and  consequently  the 
conjecture  arose  that  the  great  sea  derived  its  salts  from  the  same 
source  and  by  the  same  process.  But,  and  per  contra,  though 
these  solid  ingredients  can  not  be  taken  out  of  the  sea  by  evapo- 
ration, they  can  be  extracted  by  other  processes.  We  know  that 
the  insects  of  the  sea  do  take  out  a  portion  of  them,  and  that  the 
salt  ponds  and  arms  which,  from  time  to  time  in  the  geological 
calendar,  have  been  separated  from  the  sea,  afford  an  escape  by 
which  the  quantity  of  chloride  of  sodium  in  its  waters — the  most 
abundant  of  its  solid  ingredients — is  regulated.  The  insects  of 
the  sea  can  not  build  their  structures  of  this  salt,  for  it  would  dis- 
solve again,  and  as  fast  as  they  could  separate  it.  But  here  the 
ever-ready  atmosphere  comes  into  play,  and  assists  the  insects  in 
regulating  the  salts.  It  can  not  take  them  up  from  the  sea,  it  is 
true,  but  it  can  take  the  sea  away  from  them  ;  for  it  pumps  up  the 
water  from  these  pools  that  have  been  barred  off,  transfers  it  to 
the  clouds,  and  they  deliver  it  back  to  the  sea  as  fresh  water,  leav- 
ino'  the  salts  it  contained  in  a  solid  state  behind. 

566.  These  are  operations  that  have  been  going  on  for  ages; 
proof  that  they  are  still  going  on  is  continually  before  our  eyes ; 
for  the  "hard  w^ater"  of  our  fountains,  the  marl-banks  of  the  val- 
leys, the  salt-beds  of  the  plains,  Albion's  chalky  cliffs,  and  the 
coral  islands  of  the  sea,  are  monuments  in  attestation. 

567.  There  is  no  proof,  nor  is  there  any  reason  for  the  belief, 
that  the  sea  is  growing  Salter  or  fresher.  Hence  we  infer  that  the 
operations  of  addition  and  extraction  are  reciprocal  and  equal; 
that  the  effect  of  rains  and  rivers  in  washing  down  is  compensated 
by  the  processes  of  evaporation  and  secretion  in  taking  out. 

568.  If  the  sea  derived  its  salts  originally  from  the  rivers,  the 
geological  records  of  the  past  would  show  that  river  beds  were 
scored  out  in  the  crust  of  our  planet  before  the  sea  had  deposited 
any  of  its  fossil  shells  and  infusorial  remains  upon  it.     If,  there- 


202  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

fore,  we  admit  the  Darwin  theory,  we  must  also  admit  that  there 
was  a  period  when  the  sea  was  without  salt,  and  consequently 
without  shells  or  animals  either  of  the  silicious  or  calcareous  kind. 
If  ever  there  were  such  a  time,  it  must  have  been  when  the  rivers 
were  collecting  and  pouring  in  the  salts  which  now  make  the  brine 
of  the  ocean.  But  while  the  palasontological  records  of  the  earth, 
on  one  hand,  aiford  no  evidence  of  any  such  fresh-water  period, 
the  Mosaic  account  is  far  from  being  negative  with  its  testimony 
on  the  other.  According  to  it,  we  infer  that  the  sea  was  salt  as 
early,  at  least,  as  the  fifth  day,  for  it  was  on  that  day  of  creation 
that  the  waters  were  commanded  to  "bring  forth  abundantly  the 
moving  creature  that  hath  life."  It  is  in  obedience  to  that  com- 
mand that  the  sea  now  teems  with  organisms ;  and  it  is  marvel- 
ous how  abundantly  the  obedient  waters  do  bring  forth,  and  how 
wonderful  for  variety  as  well  as  multitude  their  progeny  is.  All 
who  pause  to  look  are  astonished  to  see  how  the  prolific  ocean 
teems  and  swarms  with  life.  The  moving  creatures  in  the  sea 
constitute  in  their  myriads  of  multitudes  one  of  the  "  wonders  of 
the  deep." 

569.  It  is  the  custom  of  Captain  Foster,  of  the  American  ship 
"  Garrick,"  who  is  one  of  my  most  patient  of  observers,  to  amuse 
himself  by  making  drawings  in  his  abstract  log  of  the  curious  ani- 
malcula3  which,  with  the  microscope,  he  finds  in  the  surface  water 
alongside ;  and  though  he  has  been  following  the  sea  for  many 
years,  he  never  fails  to  express  his  wonder  and  amazement  at  the 
immense  numbers  of  living  creatures  that  the  microscope  reveals 
to  him  in  sea  water.  Hitherto  his  examinations  related  only  to 
the  surface  waters,  but  in  the  log  now  before  me  he  went  into  the 
depths,  and  he  was  more  amazed  than  ever  to  see  how  abundantly 
the  waters  even  there  bring  forth. 

''''January  2^th,  1855.  In  examining  animalcula3  in  sea  water, 
I  have,"  says  he,  "heretofore  used  surface  water.  This  after- 
noon, after  pumping  for  some  time  from  the  stern  pump  seven  feet 
below  the  surface,  I  examined  the  water,  and  was  surprised  to 
find  that  the  fluid  was  literally  alive  with  animated  matter,  em- 
bracing beautiful  varieties."  Of  some  he  says,  "Numerous  heads, 
purple,  red,  and  variegated." 


THE  SALTS  OF  THE  SEA.  203 

570.  There  is  wonderful  meaning  in  that  word  abundantly, 
as  it  stands  recorded  in  that  Book,  and  as  it  is  even  at  this  day  re- 
peated by  the  great  waters. 

571.  So  far  the  two  records  agree,  and  the  evidence  is  clear 
that  the  sea  was  salt  when  it  received  this  command.  Do  they 
aiford  any  testimony  as  to  its  condition  previously  ?  Let  us  ex- 
amine. 

On  the  second  day  of  creation  the  waters  were  gathered  togeth- 
er unto  one  place,  and  the  dry  land  appeared.  Before  that  period, 
therefore,  there  were  no  rivers,  and  consequently  no  washings  of 
Ibrinc  by  mists,  nor  dew,  nor  rains  from  the  valleys  among  the 
hills.  The  water  covered  the  earth.  This  is  the  account  of  Rev- 
elation ;  and  the  account  which  Nature  has  written,  in  her  own 
peculiar  characters,  on  the  mountain  and  in  the  plain,  on  the  rock 
and  in  the  sea,  as  to  the  early  condition  of  our  planet,  indicates 
the  same.  The  inscriptions  on  the  geological  column  tell  that 
there  was  a  period  when  thfe  solid  parts  of  the  earth's  crust  which 
now  stand  high  in  the  air  were  covered  by  water.  The  geological 
evidence  that  it  was  so,  with  perhaps  the  exception  of  a  solitary 
mountain  peak  here  and  there,  is  conclusive ;  and  when  we  come 
to  examine  the  fossil  remains  that  are  buried  in  the  mountains  and 
scattered  over  the  plains,  we  hava  as  much  reason  to  say  that  the 
sea  was  salt  when  it  covered  or  nearly  covered  the  earth,  as  the 
naturalist,  when  he  sees  a  skull  or  bone  whitening  on  the  wayside, 
has  to  say  that  it  was  once  covered  with  flesh. 

572.  Therefore  we  have  reason  for  the  conjecture  that  the  sea 
was  salt  "  in  the  beginning,"  when  "  the  waters  under  heaven  were 
gathered  together  unto  one  place,"  and  the  dry  land  first  appeared ; 
for,  go  back  as  far  as  we  may  in  the  dim  records  which  young  Na- 
ture has  left  inscribed  upon  the  geological  column  of  her  early 
processes,  and  there  we  find  the  fossil  shell  and  the  remains  of 
marine  organisms  to  inform  us  that  when  the  foundations  of  our 
mountains  were  laid  with  granite,  and  immediately  succeeding 
that  remote  period  when  the  primary  formations  were  completed, 
the  sea  was,  as  it  is  .now,  salt ;  for  had  it  not  been  salt,  whence 
could  those  creeping  things  which  fashioned  the  sea-shells  that 
cover  the  tops  of  the  Andes,  or  those  madrepores  that  strew  the 


204       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

earth  with  solid  matter  that  has  been  secreted  from  brinj  waters, 
or  those  infusorial  deposits  which  astound  the  geologist  with  their 
magnitude  and  extent,  or  those  fossil  remains  of  the  sea  which 
have  astonished,  puzzled,  and  bewildered  man  in  all  ages — whence, 
had  not  the  sea  been  salt  when  its  metes  and  bounds  were  set, 
could  these  creatures  have  obtained  solid  matter  for  their  edifices 
and  structures.  Much  of  that  part  of  the  earth's  crust  which  man 
stirs  up  in  cultivation,  and  which  yields  him  bread,  has  been  made 
fruitful  bj  these  "salts,"  which  all  manner  of  marine  insects, 
aqueous  organisms,  and  sea-shells  have  secreted  from  the  ocean. 
Much  of  this  portion  of  our  planet  has  been  filtered  through  the 
sea,  and  its  insects  and  creeping  things  are  doing  now  precisely 
what  they  were  set  about  when  the  dry  land  appeared,  namely, 
preserving  the  purity  of  the  ocean,  and  regulating  it  in  the  due 
performance  of  its  great  offices.  As  fast  as  the  rains  dissolve  the 
salts  of  the  earth,  and  send  them  down  through  the  rivers  to  the 
sea,  these  faithful  and  everlasting  agents  of  the  Creator  elaborate 
them  into  pearls,  shells,  corals,  and  precious  things  ;  and  so,  while 
they  are  preserving  the  sea,  they  are  also  embellishing  the  land 
by  imparting  new  adaptations  to  its  soil,  fresh  beauty  and  variety 
to  its  landscapes. 

573.  In  every  department  of  nature  there  is  to  be  found  this 
self-adjusting  principle — this  beautiful  and  exquisite  system  of 
compensation,  by  which  the  operations  of  the  grand  machinery  of 
the  universe  are  maintained  in  the  most  perfect  order. 

574.  Whence  came  the  salts  of  the  sea  originally  is  a  question 
which  perhaps  never  will  be  settled  satisfactorily  to  every  philo- 
sophic mind,  but  it  is  sufficient  for  the  Christian  philosopher  to  rec- 
ollect that  the  salts  of  the  sea,  like  its  waters  and  the  granite  of 
the  hills,  are  composed  of  substances  which,  when  reduced  to  their 
simple  state,  are  found  for  the  most  part  to  be  mere  gaseous  or 
volatile  matter  of  some  kind  or  other.  Thus  we  say  that  granite 
is  generally  composed  of  feldspar,  mica,  and  quartz,  yet  these  three 
minerals  are  made  of  substances  more  or  less  volatile  in  combina- 
tion with  oxygen  gas.  Iron,  of  which  there  is  merely  a  trace,  is  the 
only  ingi-edient  which,  in  its  uncombined  and  simple  state,  is  not 
gaseous  or  volatile.     Now  was  the  feldspar  of  the  granite  origin- 


THE  SALTS  OF  THE  SEA.  205 

ally  formed  in  one  heap,  tlic  mica  in  another,  and  the  quartz  in  a 
third,  and  then  the  three  brought  together  by  some  mighty  pow- 
er, and  welded  into  the  granitic  rock  for  the  everlasting  hills  to 
stand  upon  ?  or  w^ere  they  made  into  rock  as  they  w^ere  formed  of 
the  chaotic  matter  ? 

575.  Sea  water  is  composed  of  oxygen  and  hydrogen,  and  its 
salts,  like  the  granite,  also  consist  of  gases  and  volatile  metals. 
But  whether  the  constituents  of  sea  water,  like  those  of  the  prim- 
itive rocks,  were  brought  together  in  the  process  of  formation,  and 
united  in  combination  as  we  now  find  them  in  the  ocean,  or  wheth- 
er the  sea  was  fresh  "  in  the  beginning,"  and  became  salt  by  some 
subsequent  process,  is  not  material  to  our  present  purpose.  Some 
geologists  suppose  that  in  the  chalk  period,  when  the  ammonites, 
with  their  huge  chambered  shells,  lived  in  the  sea,  the  carbonaceous 
material  required  by  these  creatures  for  their  habitations  must 
have  been  more  abundant  in  its  waters  than  it  now  is ;  but,  though 
the  constituents  of  sea  water  may  have  varied  as  to  proportions, 
they  probably  were  never,  at  least  since  "  its  waters  commenced 
to  bring  forth,"  widely  different  from  what  they  now  are. 

576.  It  is  true,  the  strange  cuttle-fish,  with  its  shell  twelve  feet 
in  circumference,  is  no  longer  found  alive  in  the  sea :  it  died  out 
with  the  chalk  period ;  but  then  its  companion,  the  tiny  nautilus, 
remains  to  tell  us  that  even  in  that  remote  period  the  proportion 
of  salt  in  sea  water  was  not  unsuited  to  its  health,  for  it  and  the 
coral  insect  have  lived  through  all  the  changes  that  our  planet  has 
undergone  since  the  sea  w^as  inhabited,  and  they  tell  us  that  its 
waters  were  salt  as  far  back,  at  least,  as  their  records  extend,  for 
they  now  build  their  edifices  and  make  their  habitations  of  the 
same  materials,  collected  in  the  same  way  that  they  did  then,  and, 
had  the  sea  been  fresh  in  the  interim,  they  too  would  have  perish- 
ed, and  their  family  would  have  become  extinct,  like  that  of  the 
great  ammonite,  which  perhaps  ceased  to  find  the  climates  of  the 
sea,  not  the  proportion  of  its  salts,  suited  to  its  well-being. 

577.  Did  any  one  who  maintains  that  the  salts  of  the  sea  were 
originally  washed  down  into  it  by  the  rivers  and  the  rains  ever 
take  the  trouble  to  compute  the  quantity  of  solid  matter  that  the 
sea  holds  in  solution  as  salts  ?     Taking  the  average  depth  of  the 


206  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

ocean  at  two  miles,  and  its  average  saltness  at  3 J  per  cent.,  it  ap- 
pears that  there  is  salt  enough  in  the  sea  to  cover  to  the  thickness 
of  one  mile  an  area  of  seven  millions  of  square  miles.  Admit  a 
transfer  of  such  a  quantity  of  matter  from  an  average  of  half  a 
mile  above  to  one  mile  below  the  sea  level,  and  astronomers  will 
show  hy  calculation  that  it  would  alter  the  length  of  the  day. 

These  seven  millions  of  cubic  miles  of  crystal  salt  have  not 
made  the  sea  any  fuller.  All  this  solid  matter  has  been  received 
into  the  interstices  of  sea  water  without  swelling  the  mass ;  for 
chemists  tell  us  that  water  is  not  increased  in  volume  by  the  salt 
it  dissolves.  Here  is  therefore  started  up  before  us  an  economy 
of  space  calculated  to  surprise  even  the  learned  author  himself  of 
the  "Plurality  of  Worlds." 

578.  There  has  been  another  question  raised  which  bears  upon 
what  has  already  been  said  concerning  the  offices  which,  in  the 
sublime  system  of  terrestrial  arrangements,  have  been  assigned  to 
the  salts  of  the  sea. 

579.  On  the  20th  of  January,  1855,  Professor  Chapman,  of  the 
University  College,  Toronto,  communicated  to  the  Canadian  Insti- 
tute a  paper  on  the  "Object  of  the  Salt  Condition  of  the  Sea," 
which,  he  maintains,  is  ^''mainly  intended  to  regulate  evctporar- 
tion.''''  To  establish  this  hypothesis,  he  shows  by  a  simple  biit 
carefully  conducted  set  of  experiments  that,  the  Salter  the  water, 
the  slower  the  evaporation  from  it ;  and  that  the  evaporation  which 
takes  place  in  24  hours  from  water  about  as  salt  as  the  average  of 
sea  water  is  0.54  per  cent,  less  in  quantity  than  from  fresh  water. 

"This  suggestion  and  these  experiments  give  additional  interest 
to  our  investigations  into  the  manifold  and  marvelous  offices 
which,  in  the  economy  of  our  planet,  have  been  assigned  by  the 
Creator  to  the  salts  of  the  sea.  It  is  difficult  to  say  what,  in  the 
Divine  arrangement,  was  the  onain  object  of  making  the  sea  salt 
and  not  fresh.  Whether  it  was  to  assist  in  the  regulation  of  cli- 
mates, or  in  the  circulation  of  the  ocean,  or  in  re-adapting  the 
earth  for  new  conditions  by  transferring  solid  portions  of  its  crust 
from  one  part  to  another,  and  giving  employment  to  the  corallines 
and  insects  of  the  sea  in  collecting  this  solid  matter  into  new 
forms,  and  presenting  it  under  different  climates  and  conditions, 


THE  SALTS  OF  THE  SEA.  207 

or  whether  the  mam  object  was,  as  the  distinguished  professor 
suggests,  to  regulate  evaporation,  it  is  not  necessary  now  or  here 
to  discuss.  I  think  w^e  may  regard  all  the  objects  of  the  salts  of 
the  sea  as  maiji  objects. 

"  But  we  see  in  the  professor's  experiments  the  dawn  of  more 
new  beauties,  and  the  appearance  of  other  exquisite  compensa- 
tions, which,  in  studying  the  'wonders  of  the  deep,'  we  have  so 
often  paused  to  contemplate  and  admire.  As  the  trade-wind  re- 
gion feeds  the  air  with  the  vapor  of  fresh  water,  the  process  of 
evaporation  is  checked,  for  the  water  which  remains,  being  Salter, 
parts  with  its  vapor  less  readily  ;  and  thus,  by  the  salts  of  the  sea, 
floods  may  be  prevented.  But  again,  if  the  evaporating  surface 
were  to  grow  Salter  and  Salter,  whence  would  the  winds  derive 
vapor  duly  to  replenish  the  earth  with  showers ;  for  the  Salter  the 
surface,  the  more  scanty  the  evaporation.  Here  is  compensation, 
again,  the  most  exquisite ;  and  we  perceive  how,  by  reason  of  the 
salts  of  the  sea,  drought  and  famine,  if  not  prevented,  may  be,  and 
probably  are,  regulated  and  controlled ;  for  that  compensation 
which  assists  to  regulate  the  amount  of  evaporation,  is  surely  con- 
cerned in  adjusting  also  the  quantity  of  rain.  Were  the  salts  of 
the  sea  lighter  instead  of  heavier  than  the  water,  they  would,  as 
they  feed  the  winds  with  moisture  for  the  cloud  and  the  rain,  re- 
main at  its  surface,  and  become  more  niggardly  in  their  supplies, 
and  finally  the  winds  would  howl  over  the  sea  in  very  emptiness, 
and  instead  of  cool  and  refreshing  sea  breezes  to  fan  the  invalid 
and  nourish  the  plants,  we  should  have  the  gentle  trade-wind 
coming  from  the  sea  in  frightful  blasts  of  parched,  and  thirsty,  and 
blighting  au*.  But  their  salts,  with  their  manifold  and  marvelous 
adaptations,  come  in  here  as  a  counterpoise,  and,  as  the  waters  at- 
tain a  certain  degree  of  saltness,  they  become  too  heavy  to  remain 
longer  in  contact  with  the  thirsty  trade-winds,  and  are  carried 
down,  because  of  their  salts,  into  the  depths  of  the  ocean ;  and 
thus  the  winds  are  dieted  with  vapor  in  due  and  wholesome  quan- 
tities. 

''  In  this  view  of  the  subject,  and  for  the  purpose  of  carrying  on 
the  investigations  which  Professor  Chapman's  interesting  paper 
suggests,  observations  upon  the  specific  gravity  of  sea  water  be- 


208  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

come  still  more  interesting.  It  is  to  be  hoped,  therefore,  that  my 
fellow-laborers  at  sea  will  not  slight  the  specific  gravity  column 
of  the  man-of-war  abstract  log." — Mauey's  Sailing  Directions^ 
7th  ed.,  p.  857. 

580.  Thus  we  behold  sea-shells  and  animalcul^e  in  a  new  light. 
May  we  not  now  cease  to  regard  them  as  beings  which  have  little 
or  nothing  to  do  in  maintaining  the  harmonies  of  creation  ?  On 
the  contrary,  do  we  not  see  in  them  the  principles  of  the  most  ad- 
mirable compensation  in  the  system  of  oceanic  circulation  ?  We 
may  even  regard  them  as  regulators,  to  some  extent,  of  climates 
in  parts  of  the  earth  far  removed  from  their  presence.  There  is 
something  suggestive,  both  of  the  grand  and  the  beautiful,  in  the 
idea  that,  while  the  insects  of  the  sea  are  building  up  their  coral 
islands  in  the  perpetual  summer  of  the  tropics,  they  are  also  en- 
gaged in  dispensing  warmth  to  distant  parts  of  the  earth,  and  in 
mitigating  the  severe  cold  of  the  Polar  winter. 

581.  Surely  an  hypothesis  which,  being  followed  out,  suggests 
so  much  design,  such  perfect  order  and  arrangement,  and  so  many 
beauties  for  contemplation  and  admiration  as  does  this,  which,  for 
the  want  of  a  better,  I  have  ventured  to  offer  with  regard  to  the 
solid  matter  of  the  sea  water,  its  salts  and  its  shells — surely  such 
an  hypothesis,  though  it  be  not  based  entirely  on  the  results  of 
actual  observation,  can  not  be  regarded  as  wholly  vain  or  as  alto- 
gether profitless. 


THE  EQUATORIAL  CLOUD-RING.  209 


CHAPTER  X. 

THE   EQUATORIAL   CLOUD-EINa. 

The  "Doldrums,"  (J  583.— Oppressive  Weather,  586.— Offices  of  the  Clouds,  587.— 
Weight  for  the  Wind,  589.  —  Galileo  and  the  Pump-maker,  590.  —  Temperature 
and  Pressure  under  the  Cloud-ring,  59L  —  Its  effect  upon  Climate,  596.-  — Its  Of- 
fices, 599. — Whence  come  the  Vapors  that  form  the  Cloud-ring]  602. — Its  Appear- 
ance, 605. 

582.  Seafaeing  people  have,  as  if  by  common  consent,  divided 
the  ocean  off  into  regions,  and  characterized  them  according  to 
the  winds  ;  e.  g,^  there  are  the  "trade- wind  regions,"  the  "varia- 
bles," the  "horse  latitudes,"  the  "  doldrums,"  etc.  The  "horse 
latitudes"  are  the  belts  of  calms  and  light  airs  (§  131)  which  bor- 
der the  Polar  edge  of  the  northeast  trades.  Thej  were  so  called 
from  the  circumstance  that  vessels  formerly  bound  from  New  En- 
gland to  the  West  Indies,  with  a  deck-load  of  horses,  were  often 
so  delayed  in  this  calm  belt  of  Cancer,  that,  for  the  want  of  water 
for  their  animals,  they  were  compelled  to  throw  a  portion  of  them 
overboard. 

583.  The  "  equatorial  doldrums"  is  another  of  these  calm  places 
(§  135).  Besides  being  a  region  of  calms  and  baffling  winds,  it  is 
a  region  noted  for  its  rains  and  clouds,  which  make  it  one  of  the 
most  oppressive  and  disagreeable  places  at  sea.  The  emigrant 
ships  from  Europe  for  Australia  have  to  cross  it.  They  are  often 
baffled  in  it  for  two  or  three  weeks ;  then  the  children  and  the 
passengers  who  are  of  delicate  health  suffer  most.  It  is  a  fright- 
ful grave-yard  on  the  way-side  to  that  golden  land. 

584.  A  vessel  bound  into  the  southern  hemisphere  from  Europe 
or  America,  after  clearing  the  region  of  variable  winds  and  cross- 
ing the  "horse  latitudes,"  enters  the  northeast  trades.  Here  the 
mariner  finds  the  sky  sometimes  mottled  with  clouds,  but  for  the 
most  part  clear.  Here,  too,  he  finds  his  barometer  rising  and  fall- 
ing under  the  ebb  and  flow  of  a  regular  atmospherical  tide,  which 


210  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

gives  a  high  and  low  barometer  every  day  with  such  regularity 
that  the  hour  within  a  few  minutes  may  be  told  by  it.  The  rise 
and  fall  of  this  tide,  measured  by  the  barometer,  amounts  to  about 
one  tenth  (0.1)  of  an  inch,  and  it  occurs  daily  and  every  where 
between  the  tropics ;  the  maximum'  about  lOh.  30m.  A.M.,  the 
minimum  between  4h.  and  5h.  P.M.,  with  a  second  maximum  and 
minimum  about  10  P.M.  and  5  A.M.*  The  diurnal  variation  of 
the  needle  changes  also  with  the  turning  of  these  invisible  tides. 
Continuing  his  course  toward  the  equinoctial  line,  the  navigator 
observes  his  thermometer  to  rise  higher  and  higher  as  he  ap- 
proaches it ;  at  last,  entering  the  region  of  equatorial  calms  and 
rains,  he  feels  the  weather  to  become  singularly  close  and  op- 
pressive ;  he  discovers  here  that  the  elasticity  of  feeling  which  he 
breathed  from  the  trade- wind  air  has  forsaken  him ;  he  has  enter- 
ed the  doldrums,  and  is  under  the  "  cloud-ring." 

585.  Escaping  from  this  gloomy  region,  and  entering  the  south- 
east trades  beyond,  his  spirits  revive,  and  he  turns  to  his  log-book 
to  see  what  changes  are  recorded  there.  He  is  surprised  to  find 
that,  notwithstanding  the  oppressive  weather  of  the  rainy  latitudes, 
both  his  thermometer  and  barometer  stood,  while  in  them,  lower 
than  in  the  clear  weather  on  either  side  of  them  ;  that  just  before 
entering  and  just  before  leaving  the  rainy  parallels,  the  mercury 
of  the  thermometer  and  barometer  invariably  stands  higher  than 
it  does  when  within  them,  even  though  they  include  the  equator. 
In  crossing  the  equatorial  doldrums  he  has  passed  a  ring  of  clouds 
that  encircles  the  earth. 

586.  I  find  in  the  journal  of  the  late  Commodore  Arthur  Sin- 
clair, kept  on  board  the  United  States  frigate  Congress  during  a 
cruise  to  South  America  in  1817-18,  a  picture  of  the  weather  un- 
der this  cloud-ring  that  is  singularly  graphic  and  striking.  He 
encountered  it  in  the  month  of  January,  1818,  between  the  paral- 
lel of  4P  north  and  the  equator,  and  between  the  meridians  of  19° 
and  23°  west.     He  says  of  it : 

"  This  is  certainly  one  of  the  most  unpleasant  regions  in  our 
globe.     A  dense,  close  atmosphere,  except  for  a  few  hours  after  a 

*  See  paper  on  Meteorological  Observations  in  India,  by  Colonel  Sykes,  Philosoph- 
ical Transactions  for  1850,  part  ii.,  page  297. 


THE  EQUATORIAL  CLOUD-RING.  211 

thunder-storm,  during  wliich  time  torrents  of  rain  fall,  when  the 
air  becomes  a  little  refreshed ;  but  a  hot,  glowing  sun  soon  heats 
it  again,  and  but  for  your  awnings,  and  the  little  air  put  in  circu- 
latioii  by  the  continual  flapping  of  the  ship's  sails,  it  would  be  al- 
most insufferable.  No  person  who  has  not  crossed  this  region 
can  form  an  adequate  idea  of  its  unpleasant  effects.  You  feel  a 
degree  of  lassitude  unconquerable,  which  not  even  the  sea-bathing, 
which  every  where  else  proves  so  salutary  and  renovating,  can 
dispel.  Except  when  in  actual  danger  of  shipwreck,  I  never  spent 
twelve  more  disagreeable  days  in  the  professional  part  of  my  life 
than  in  these  calm  latitudes. 

"I  crossed  the  line  on  the  17th  of  January,  at  eight  A.M.,  in 
longitude  21°  20^,  and  soon  found  I  had  surmounted  all  the  diffi- 
culties consequent  to  that  event ;  that  the  breeze  continued  to 
fi'eshen  and  draw  round  to  the  south-southeast,  bringing  with  it  a 
clear  sky  and  most  heavenly  temperature,  renovating  and  refresh- 
ing beyond  description.  Nothing  w^as  now  to  be  seen  but  cheer- 
ful countenances,  exchanged  as  by  enchantment  from  that  sleepy 
sluggishness  which  had  borne  us  all  down  for  the  last  two  weeks." 

587.  One  need  not  go  to  sea  to  perceive  the  grand  work  which 
the  clouds  perform  in  collecting  moisture  from  the  crystal  vaults 
of  the  sky,  in  sprinkling  it  upon  the  fields,  and  making  the  hills 
glad  with  showers  of  rain.  Winter  and  summer,  "the  clouds  drop 
fatness  upon  the  earth."  This  part  of  their  office  is  obvious  to  all, 
and  I  do  not  propose  to  consider  it  now.  But  the  sailor  at  sea 
observes  phenomena  and  witnesses  operations  in  the  terrestrial 
economy  which  tell  him  that,  in  the  beautiful  and  exquisite  ad- 
justments of  the  grand  machinery  of  the  atmosphere,  the  clouds 
have  other  important  offices  to  perform  besides  those  merely  of 
dispensing  showers,  of  producing  the  rains,  and  of  weaving  man- 
tles of  snow  for  the  protection  of  our  fields  in  winter.  As  import- 
ant as  are  these  offices,  the  philosophical  mariner,  as  he  changes 
his  sky,  is  reminded  that  the  clouds  have  commandments  to  ful- 
fill, which,  though  less  obvious,  are  not  therefore  the  less  benign 
in  their  influences,  or  the  less  worthy  of  his  notice.  He  beholds 
them  at  work  in  moderating  the  extremes  of  heat  and  cold,  and  in 
mitigating  climates.     At  one  time  they  spread  themselves  out; 

0 


212  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

they  cover  the  earth  as  with  a  mantle;  they  prevent  radiation 
from  its  crust,  and  keep  it  warm.  At  another  time,  they  interpose 
between  it  and  the  smi ;  they  screen  it  from  his  scorching  rays, 
and  protect  the  tender  plants  from  his  heat,  the  land  from  the 
drouo'lit ;  or,  like  a  garment,  they  overshadow  the  sea,  defending  its 
waters  from  the  intense  forces  of  evaporation.  Having  performed 
these  offices  for  one  place,  they  are  evaporated  and  given  up  to  the 
sunbeam  and  the  winds  again,  to  be  borne  on  their  wings  away  to 
other  places  which  stand  in  need  of  like  offices. 

588.  Familiar  with  clouds  and  sunshine,  the  storm  and  the 
calm,  and  all  the  phenomena  which  find  expression  in  the  physi- 
cal geography  of  the  sea,  the  right-minded  mariner,  as  he  contem- 
plates "the  cloud  without  rain,"  ceases  to  regard  it  as  an  empty 
thing ;  he  perceives  that  it  performs  many  important  offices ;  he 
regards  it  as  a  great  moderator  of  heat  and  cold — as  a  "compen- 
sation" in  the  atmospherical  mechanism  which  makes  the  perform- 
ance of  the  grand  machine  perfect. 

589.  Marvelous  are  the  offices  and  wonderful  is  the  constitu- 
tion of  the  atmosphere.  Indeed,  I  know  of  no  subject  more  fit  for 
profitable  thought  on  the  part  of  the  truth-loving,  knowledge- 
seeking  student,  be  he  seaman  or  landsman,  than  that  afforded  by 
the  atmosphere  and  its  offices.  Of  all  parts  of  the  physical  ma- 
chinery, of  all  the  contrivances  in  the  mechanism  of  the  universe, 
the  atmosphere,  with  its  offices  and  its  adaptations,  appears  to  me 
to  be  the  most  wonderful,  sublime,  and  beautiful.  In  its  construc- 
tion, the  perfection  of  knowledge  is  involved.  The  perfect  man  of 
Uz,  in  a  moment  of  inspiration,  thus  bursts  forth  in  laudation  of 
this  part  of  God's  handiwork,  demanding  of  his  comforters:  "But 
where  shall  wisdom  be  found,  and  where  is  the  place  of  under- 
standing ?  The  depth  saith,  it  is  not  in  me  ;  and  the  sea  saith,  it 
is  not  with  me.  It  can  not  be  gotten  for  gold,  neither  shall  silver 
be  weighed  for  the  price  thereof.  No  mention  shall  be  made  of 
coral  or  of  pearls,  for  the  price  of  wisdom  is  above  rubies. 

"Whence,  then,  cometh  wisdom,  and  where  is  the  place  of  un> 
derstanding?  Destruction  and  Death  say,  we  have  heard  the  fame 
thereof  with  our  ears. 

"God  understandeth  the  way  thereof,  and  he  knoweth  the  place 


THE  EQUATORIAL  CLOUD-RING.  213 

thereof;  for  he  looketh  to  the  ends  of  the  earth,  and  seeth  under 
the  whole  heaven ;  to  tnaJce  the  weight  for  the  winds  /  and  he 
weigheth  the  waters  by  measure.  When  he  made  a  decree  for  the 
rain,  and  a  way  for  the  lightning  of  the  thunder ;  then  did  he  see 
it,  and  declare  it ;  he  prepared  it,  yea,  and  searched  it  out."* 

590.  When  the  pump-maker  came  to  ask  Galileo  to  explain 
how  it  was  that  his  pump  would  not  lift  water  higher  than  thirty- 
two  feet,  the  philosopher  thought,  but  was  afraid  to  say,  it  was 
owing  to  "weight  of  the  winds;''  and  though  the  fact  that  the  air 
has  weight  is  here  so  distinctly  announced,  philosophers  never 
recognized  the  fact  until  within  comparatively  a  recent  period,  and 
then  it  was  proclaimed  by  them  as  a  great  discovery.  Neverthe- 
less, the  fact  was  set  forth  as  distinctly  in  the  book  of  nature  as  it 
is  in  the  book  of  revelation  ;  for  the  infant,  in  availing  itself  of  at- 
mospherical pressure  to  draw  milk  from  its  mother's  breast,  un- 
consciously proclaimed  it. 

591.  Both  the  thermometer  and  the  barometer  (§  585)  stand 
lower  under  this  cloud-ring  than  they  do  on  either  side  of  it.  After 
having  crossed  it,  and  referred  to  the  log-book  to  refresh  his  mind 
as  to  the  observations  there  entered  with  regard  to  it,  the  atten- 
tive navigator  may  perceive  how  this  belt  of  clouds,  by  screening- 
the  parallels  over  which  he  may  have  found  it  to  hang  from  the 
sun's  rays,  not  only  promotes  the  precipitation  which  takes  place 
within  these  parallels  at  certain  periods,  but  how,  also,  the  rains 
are  made  to  change  the  places  upon  which  they  are  to  fall;  and 
how,  by  traveling  with  the  calm  belt  of  the  equator  up  and  down 
the  earth,  this  cloud-ring  shifts  the  surface  from  which  the  heat- 
ing rays  of  the  sun  are  to  be  excluded ;  and  how,  by  this  opera- 
tion, tone  is  given  to  the  atmospherical  circulation  of  the  world, 
and  vigor  to  its  vegetation. 

592.  Having  traveled  with  the  calm  belt  to  the  north  or  south, 
the  cloud-ring  leaves  the  sky  about  the  equator  clear ;  the  rays  of 
the  torrid  sun  pour  down  upon  the  crust  of  the  earth  there,  and 
raise  its  temperature  to  a  scorching  heat.  The  atmosphere  dances 
(§  352),  and  the  air  is  seen  trembling  in  ascending  and  descend- 
ing columns,  with  busy  eagerne&s  to  conduct  the  heat  off  and  de- 

*  Job,  chap,  xxviii. 


214  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

liver  it  to  the  regions  aloft,  where  it  is  required  to  give  momentum 
to  the  air  in  its  general  channels  of  circulation.  The  dry  season 
continues ;  the  sun  is  vertical ;  and  finally  the  earth  becomes 
parched  and  dry ;  the  heat  accumulates  faster  than  the  air  can 
carry  it  away  ;  the  plants  begin  to  -vVither,  and  the  animals  to  per- 
ish. Then  comes  the  mitigating  cloud-ring.  The  burning  rays 
of  the  sun  are  intercepted  by  it :  the  place  for  the  absorption  and 
reflection,  and  the  delivery  to  the  atmosphere  of  the  solar  heat, 
is  changed ;  it  is  transferred  from  the  upper  surface  of  the  earth 
to  the  upper  surface  of  the  clouds. 

593.  Radiation  from  land  and  sea  below  the  cloud-belt  is  thus 
interrupted,  and  the  excess  of  heat  in  the  earth  is  delivered  to  the 
air,  and  by  absorption  carried  up  to  the  clouds,  and  there  trans- 
ferred to  their  vapors  to  prevent  excess  of  precipitation. 

594.  In  the  mean  time,  the  trade-winds  north  and  south  are 
pouring  into  this  cloud- covered  receiver,  as  the  calm  and  rain  belt 
of  the  equator  may  be  called,  fresh  supplies  in  the  shape  of  cease- 
less volumes  of  heated  air,  which,  loaded  to  saturation  with  vapor, 
has  to  rise  above  and  get  clear  of  the  clouds  before  it  can  com- 
mence the  process  of  cooling  by  radiation.  In  the  mean  time, 
also,  the  vapors  which  the  trade-winds  bring  from  the  north  and 
the  south,  expanding  and  growing  cooler  as  they  ascend,  are  be- 
ing: condensed  on  the  lower  side  of  the  cloud  stratum,  and  their  la- 
tent  heat  is  set  free,  to  check  precipitation  and  prevent  a  flood, 

595.  While  this  process  and  these  operations  are  going  on  upon 
the  nether  side  of  the  cloud-ring,  one  not  less  important  is,  we 
may  imagine,  going  on  upon  the  upper  side.  There,  from  sunrise 
to  sunset,  the  rays  of  the  sun  are  pouring  down  without  intermis- 
sion. Every  day,  and  all  day  long,  they  play  with  ceaseless  ac- 
tivity upon  the  upper  surface  of  the  cloud  stratum.  When  they 
become  too  powerful,  and  convey  more  heat  to  the  cloud  vapors 
than  the  cloud  vapors  can  reflect  and  give  off  to  the  air  above  them, 
then,  with  a  beautiful  elasticity  of  character,  the  clouds  absorb  the 
surplus  heat.  They  melt  away,  become  invisible,  and  retain,  in  a 
latent  and  harmless  state,  until  it  is  wanted  at  some  other  place 
and  on  some  other  occasion,  the  heat  thus  imparted. 

596.  We  thus  have  an  insight  into  the  operations  which  are  go- 


THE  EQUATORIAL  CLOUD-RING.  215 

ing  on  in  the  equatorial  belt  of  precipitation,  and  this  insight  is 
sufficient  to  enable  us  to  perceive  that  exquisite  indeed  are  the  ar- 
rangements which  Nature  has  provided  for  supplying  this  calm 
belt  with  heat,  and  for  pushing  the  snow-line  there  high  up  above 
the  clouds,  in  order  that  the  atmosphere  may  have  room  to  ex- 
pand, to  rise  up,  overflow,  and  course  back  into  its  channels  of 
healthful  circulation.  As  the  vapor  is  condensed  and  formed  into 
drops  of  rain,  a  twofold  object  is  accomplished :  coming  from  the 
cooler  regions  of  the  clouds,  the  rain-drops  are  cooler  than  the  air 
and  earth  below;  they  descend,  and  by  absorption  take  up  the  heat 
which  has  been  accumulating  in  the  earth's  crust  during  the  dry 
season,  and  which  can  not  now  escape  by  radiation.  Thus  this 
cloud-ring  modifies  the  climate  of  all  places  beneath  it ;  overshad- 
owing, at  different  seasons,  all  parallels  from  5°  south  to  15°  north, 

597.  In  the  process  of  condensation,  these  rain-drops,  on  the 
other  hand,  have  set  free  a  vast  quantity  of  latent  heat,  which  has 
been  gathered  up  with  the  vapor  from  the  sea  by  the  trade-winds 
and  brought  hither.  The  caloric  thus  liberated  is  taken  by  the 
air  and  carried  up  aloft  still  farther,  to  keep,  at  the  proper  distance 
from  the  earth,  the  line  of  perpetual  congelation.  Were  it  possi- 
ble to  trace  a  thermal  curve  in  the  upper  regions  of  the  air  to  rep-, 
resent  this  line,  we  should  no  doubt  find  it  mounting  sometimes  at 
the  equator,  sometimes  on  this  side,  and  sometimes  on  that  of  it, 
but  always  so  mounting  as  to  overleap  this  .cloud-ring.  This 
thermal  line  would  not  ascend  always  over  the  same  parallels :  it 
would  ascend  over  those  between  which  this  ring  happens  to  be ; 
and  the  distance  of  this  ring  from  the  equator,  north  or  south,  is 
regulated  according  to  the  seasons. 

598.  If  we  imagine  the  atmospherical  equator  to  be  always 
where  the  calm  belt  is  which  separates  the  northeast  from  the 
southeast  trade-winds,  then  the  loop  in  the  thermal  curve,  which 
should  represent  the  line  of  perpetual  congelation  in  the  air,  would 
be  always  found  to  stride  this  equator ;  and  it  may  be  supposed 
that  a  thermometer,  kept  sliding  on  the  surface  of  the  earth  so  as 
always  to  be  in  the  middle  of  this  rain-belt,  would  show  very  near- 
ly the  same  temperature  all  the  year  round ;  and  so,  too,  would  a 
barometer  the  same  pressure. 


216       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

599.  Eeturning  and  taking  up  the  train  of  contemplation  as  to 
the  office  which  this  belt  of  clouds,  as  it  encircles  the  earth,  per- 
forms in  the  system  of  oceanic  adaptations,  we  may  see  how  the 
cloud-ring  and  calm  zone  which  it  overshadows  perform  the  office 
"both  of  ventricle  and  auricle  in  the  immense  atmospherical  heart, 
where  the  heat  and  the  forces  which  give  vitality  and  power  to  the 
system  are  brought  into  play — where  dynamical  strength  is  gath- 
ered, and  an  impulse  given  to  the  air  sufficient  to  send  it  thence 
through  its  long  and  tortuous  channels  of  circulation. 

600.  Thus  this  ring,  or  band,  or  belt  of  clouds  is  stretched 
around  our  planet  to  regulate  the  quantity  of  precipitation  in  the 
rain-belt  beneath  it ;  to  preserve  the  due  quantum  of  lieat  on  the 
face  of  the  earth  ;  to  adjust  the  winds  ;  and  send  out  for  distribu- 
tion to  the  four  corners,  vapors  in  proper  quantities  to  make  up  to 
each  river-basin,  climate,  and  season,  its  quota  of  sunshine,  cloud, 
and  moisture.  Like  the  balance-wheel  of  a  well-constructed  chro- 
nometer, this  cloud-ring  affords  the  grand  atmospherical  machine 
the  most  exquisitely-arranged  self-convpensatio7i.  If  the  sun  fail 
in  his  supply  of  heat  to  this  region,  more  of  its  vapors  are  con- 
densed, and  heat  is  discharged  from  its  latent  store- houses  in  quan- 
tities just  sufficient  to  keep  the  machine  in  the  most  perfect  com- 
pensation. If,  on  the  other  hand,  too  much  heat  be  found  to  ac- 
company the  rays  of  the  sun  as  they  impinge  upon  the  upper  cir- 
cumference of  this  belt,  then  again  on  that  side  the  means  of  self- 
compensation  are  ready  at  hand  ;  so  much  of  the  cloud-surface 
as  may  be  requisite  is  then  resolved  into  invisible  vapor — for  of 
invisible  vapor  are  made  the  vessels  wherein  the  surplus  heat  from 
the  sun  is  stored  away  and  held  in  the  latent  state  until  it  is  call- 
ed for,  w^hen  instantly  it  is  set  free,  and  becomes  a  palpable  and 
active  agent  in  the  grand  design. 

601.  That  the  thermometer  stands  invariahly  lower  (§  591)  be- 
neath this  cloud-belt  than  it  does  on  either  side  of  it,  has  not,  so 
far  as  my  researches  are  concerned,  been  made  to  appear  by  ac- 
tual observation,  for  the  observations  in  my  possession  have  not 
yet  been  fully  discussed  concerning  the  temperature  of  the  air. 
But  that  the  temperature  of  the  air  at  the  surface  under  this  cloud- 
ring  is  lower,  is  a  theoretical  deduction  as  susceptible  of  demon- 


THE  EQUATORIAL  CLOUD-RING.  217 

stration  as  is  the  rotation  of  the  earth  on  its  axis.     Indeed,  Na- 
ture lierself  has  hung  a  thermometer  under  this  cloud-belt  that  is 
•more  perfect  tlian  any  that  man  can  construct,  and  its  indications 
are  not  to  be  mistaken. 

602.  Where  do  the  vapors  which  form  this  cloud-ring,  and 
which  are  here  condensed  and  poured  down  into  the  sea  as  rain, 
come  from?  They  come  from  the  trade-wind  regions  (§  162); 
under  the  cloud-ring  they  rise  up ;  as  they  rise  up,  they  expand ; 
and  as  they  expand,  they  grow  cool,  form  clouds,  and  then  are 
condensed  into  rains  ;  moreover,  it  requires  no  mercurial  instru- 
ment of  human  device  to  satisfy  us  that  the  air  which  brings  the 
vapor  for  these  clouds  can  not  take  it  up  and  let  it  down  at  the 
same  temperature.  Precipitation  and  evaporation  are  the  converse 
of  each  other,  and  the  same  air  can  not  precipitate  and  evaporate, 
take  up  and  let  down  water,  at  one  and  the  same  temperature. 
As  the  temperature  of  the  air  is  raised,  its  capacity  for  receiving 
and  retaining  water  in  the  state  of  vapor  is  increased  ;  as  the  tem- 
perature of  the  air  is  lessened,  its  capacity  for  retaining  that  moist- 
ure is  diminished.  These  are  physical  laws,  and  therefore,  when 
we  see  water  dripping  from  the  atmosphere,  we  need  no  instru- 
ment to  tell  us  that  the  elasticity  of  the  vapor  so  condensed,  and 
falling  in  drops,  is  less  than  was  its  elasticity  when  it  was  taken 
up  from  the  surface  of  the  ocean  as  water,  and  went  up  into  the 
clouds  as  vapor. 

603.  Hence  we  infer  that,  when  the  vapors  of  sea  water  are 
condensed,  the  heat  which  was  necessary  to  sustain  them  in  the 
vapor  state,  and  which  was  borrowed  from  the  ocean,  is  parted 
with,  and  that  therefore  they  were  subjected,  in  the  act  of  con- 
densation, to  a  lower  temperature  than  they  were  in  the  act  of 
evaporation.  Ceaseless  precipitation  goes  on  under  this  cloud- 
ring.  Evaporation  under  it  is  "'suspended  almost  entirely.  We 
know  that  the  trade-winds  encircle  the  earth  ;  that  they  blow  per- 
petually ;  that  they  come  from  the  north  and  the  south,  and  meet 
each  other  near  the  equator;  therefore  we  infer  that  this  line  of 
meeting  extends  around  the  world.  By  the  rainy  seasons  of  the 
torrid  zone,  except  where  it  may  be  broken  by  the  continents,  we 
can  trace  the  declination  of  this  cloud-ring,  stretched  like  a  girdle 


218       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

around  our  planet,  uj)  and  down  the  eartli :  it  travels  up  and  down 
the  ocean,  as  from  north  to  south  and  back. 

604.  It  is  broader  than  the  belt  of  calms  out  of  which  it  rises. 
As  the  air,  with  its  vapors,  rises  up  in  this  calm  belt  and  ascends, 
these  vapors  are  condensed  into  clouds  (§  602),  and  this  condensa- 
tion is  followed  by  a  turgid  intumescence,  which  causes  the  clouds 
to  overflow  the  calm  belt,  as  it  were,  both  to  the  north  and  the 
south.  The  air  flowing  off  in  the  same  direction  assumes  the 
character  of  winds  that  form  the  upper  currents  that  are  counter 
(Plate  I.)  to  the  trade-winds.  These  currents  carry  the  clouds 
still  farther  to  the  north  and  south,  and  thus  make  the  cloud- 
ring  broader.  At  least,  we  infer  such  to  be  the  case,  for  the  rains 
are  found  to  extend  out  into  the  trade-winds,  and  often  to  a 
considerable  distance  both  to  the  north  and  the  south  of  the  calm 
belt. 

605.  Were  this  cloud-ring  luminous,  and  could  it  be  seen  by  an 
observer  from  one  of  the  planets,  it  would  present  to  him  an  ap- 
pearance not  unlike  the  rings  of  Saturn  do  to  us.  Such  an  ob- 
server would  remark  that  this  cloud-ring  of  the  earth  has  a  motion 
contrary  to  that  of  the  axis  of  our  planet  itself — that  while  the 
earth  was  revolving  rapidly  from  west  to  east,  he  would  observe 
the  cloud-ring  to  go  slowly,  but  only  relatively,  from  east  to  west. 
As  the  winds  which  bring  this  cloud-vapor  to  this  region  of  calms 
rise  up  with  it,  the  earth  is  slipping  from  under  them ;  and  thus 
the  cloud-ring,  though  really  moving  from  west  to  east  with  the 
earth,  goes  relatively  slower  than  the  earth,  and  would  therefore 
appear  to  require  a  longer  time  to  complete  a  revolution. 

606.  But,  unlike  the  rings  of  Saturn  through  the  telescope,  the 
outer  surface,  or  the  upper  side  to  us,  of  this  cloud-ring  would  ap- 
pear exceedingly  jagged,  rough  and  uneven. 

607.  The  rays  of  the  sun,  playing  upon  this  peak  and  then  upon 
that  of  the  upper  cloud-surface,  melt  away  one  set  of  elevations 
and  create  another  set  of  depressions.  The  whole  stratum  is,  it 
may  be  imagined,  in  the  most  turgid  state  ;  it  is  in  continued 
throes  when  viewed  from  above  ;  the  heat  which  is  liberated  from 
below  in  the  process  of  condensation,  the  currents  of  warm  air  as- 
cending from  the  earth,  and  of  cool  descending  from  the  sky,  all, 


THE  EQUATORIAL  CLOUD-RING.  219 

we  may  well  conceive,  tend  to  keep  the  upper  cloud-surface  in  a 
perpetual  state  of  agitation,  upheaval,  and  depression. 

608.  Imagine  in  such  a  cloud-stratum  an  electrical  discharge  to 
take  place  ;  the  report,  being  caught  up  by  the  cloud-ridges  above, 
is  passed  from  peak  to  peak,  and  repeated  from  valley  to  valley, 
until  the  last  echo  dies  away  in  the  mutterings  of  the  distant  thun- 
der. How  often  do  we  hear  the  voice  of  the  loud  thunder  rum- 
bhng  and  rolling  away  above  the  cloud-surface,  like  the  echo  of 
artillery  discharged  among  the  hills ! 

609.  Hence  we  perceive  or  infer  that  the  clouds  intercept  the 
progress  of  sound,  as  well  as  of  light  and  heat,  through  the  atmos- 
phere, and  that  this  upper  surface  is  often  like  Alpine  regions, 
which  echo  back  and  roll  along  with  rumbling  noise  the  mutter- 
ings of  the  distant  thunder. 

610.  It  is  by  trains  of  reasoning  like  this  that  we  are  continu- 
ally reminded  of  the  interest  which  attaches  to  the  observations 
which  the  mariner  is  called  on  to  make.  There  is  no  expression 
uttered  by  nature  which  is  unworthy  of  our  most  attentive  consid- 
eration— for  no  physical  fact  is  too  bald  for  observation — and  mar- 
iners, by  registering  in  their  logs  the  kind  of  lightning,  whether 
sheet,  forked,  or  streaked,  and  the  kind  of  thunder,  whether  roll- 
ing, muttering,  or  sharp,  may  be  furnishing  facts  which  will  throw 
much  light  on  the  features  and  character  of  the  clouds  in  different 
latitudes  and  seasons.  Physical  facts  are  the  language  of  Nature, 
and  every  expression  uttered  by  her  is  worthy  of  our  most  atten- 
tive consideration,  for  it  is  the  voice  of  Wisdom. 


220  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTEE'  XI. 

ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS. 

Nature  regarded  as  a  Whole,  <$»  6n. — The  Dead  Sea,  614. — Annual  fall  of  Rain  upon 
less  now  than  formerly,  615. — The  Caspian,  617. — The  great  American  Lakes,  622. 
—Gulf  of  Mexico,  its  Depth,  624.— The  Effect  of  cutting  off  the  Gulf  Stream,  625. 
— Uprising  of  Continents,  627.  —  The  Causes  that  change  the  Water-level  of  a 
country,  633. — Foot-prints  of  the  Clouds,  638. — Andes  rising  from  the  Sea,  640. — 
Rains  for  Europe,  651. — Terrestrial  Adaptations,  655. — Evaporating  Force  in  the 
Mediterranean,  661. — Display  of  Harmony,  663. — The  Age  of  the  Andes  and  Dead 
Sea  compared,  671. 

611.  Propeely  to  appreciate  the  various  offices  wliicli  tlie 
winds  and  the  waves  perform,  we  must  regard  nature  as  a  whole, 
for  all  the  departments  thereof  are  intimately  connected.  If  we 
attempt  to  study  in  one  of  them,  w^e  often  find  ourselves  tracing 
clews  which  lead  us  off  insensibly  into  others,  and,  before  we  are 
aware,  we  discover  ourselves  exploring  the  chambers  of  some  oth- 
er department. 

612.  The  study  of  drift  takes  the  geologist  out  to  sea,  and  re- 
minds him  that  a  knowledge  of  waves,  winds,  and  currents,  of 
navigation  and  hydrography,  are  closely  and  intimately  connected 
with  his  favorite  pursuit. 

613.  The  astronomer  directs  his  telescope  to  the  most  remote 
star,  or  to  the  nearest  planet  in  the  sky,  and  makes  an  observation 
upon  it.  He  can  not  reduce  this  observation,  nor  make  any  use 
of  it,  until  he  has  availed  himself  of  certain  principles  of  optics  ; 
until  he  has  consulted  the  thermometer,  gauged  the  atmosphere, 
and  considered  the  effect  of  heat  in  changing  its  powers  of  refrac- 
tion. In  order  to  adjust  the  pendulum  of  his  clock  to  the  right 
length,  he  has  to  measure  the  water  of  the  sea  and  weigh  the  earth. 
He,  too,  must  therefore  go  into  the  study  of  the  tides ;  he  must 
examine  the  earth's  crust,  and  consider  the  matter  of  which  it  is 
composed,  from  pole  to  pole,  circumference  to  centre  ;  and  in  doing 
this,  he  finds  himself,  in  his  researches,  right  alongside  of  the  nav- 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  221 

igator,  the  geologist,  and  tlie  meteorologist,  with  a  host  of  other 
good  fellows,  each  one  holding  bj  the  same  thread,  and  following 
it  up  into  the  same  labyrinth — all,  it  may  be,  with  different  ob- 
jects in  view,  but  nevertheless,  each  thread  will  be  sure  to  lead 
them  where  there  are  stores  of  knowledge  for  all,  and  instruction 
for  each  one  in  particular.  And  thus,  in  undertaking  to  explore 
the  physical  geography  of  the  sea,  I  have  found  myself  standing 
side  by  side  with  the  geologist  on  the  land,  and  with  him,  far 
away  from  the  sea-shore,  engaged  in  considering  some  of  the  phe- 
nomena which  the  inland  basins  of  the  earth — those  immense  in- 
dentations on  its  surface  that  have  no  sea-drainage — present  for 
contemplation  and  study, 

614  Among  the  most  interesting  of  these  is  that  of  the  Dead 
Sea.  Lieutenant  Lynch,  of  the  United  States  Navy,  has  run  a 
level  from  that  sea  to  the  Mediterranean,  and  finds  the  former  to 
be  about  one  thousand  three  hundred  feet  below  the  general  sea- 
level  of  the  earth.  In  seeking  to  account  for  this  great  difference 
of  water  level,  the  geologist  examines  the  neighboring  region,  and 
calls  to  his  aid  the  forces  of  elevation  and  depression  which  are 
supposed  to  have  resided  in  the  neighborhood ;  he  then  points  to 
them  as  the  agents  which  did  the  work.  Truly  they  are  mighty 
agents,  and  they  have  diversified  the  surface  of  the  earth  with  the 
most  towering  monuments  of  their  power.  But  is  it  necessary  to 
suppose  that  they  resided  in  the  vicinity  of  this  region?  May 
they  not  have  come  from  the  sea,  and  been,  if  not  in  this  case,  at 
least  in  the  case  of  other  inland  basins,  as  far  removed  as  the  oth- 
er hemisphere  ?  This  is  a  question  which  I  do  not  pretend  to  an- 
swer definitely.  But  the  inquiry  as  to  the  geological  agency  of 
the  winds  in  such  cases  is  a  question  which  my  investigations 
have  suggested.  It  has  its  seat  in  the  sea,  and  therefore  I  pro- 
pound it  as  one  which,  in  accounting  for  the  formation  of  this  or 
that  inland  basin,  is  worthy,  at  least,  of  consideration. 

615.  Is  there  any  evidence  that  the  annual  amount  of  precipi- 
tation upon  the  water-shed  of  the  Dead  Sea,  at  some  former  pe- 
riod, was  greater  than  the  annual  amount  of  evaporation  from  it 
now  is  ?  If  yea,  from  what  part  of  the  sea  did  the  vapor  that  sup- 
plied the  excess  of  that  precipitation  come,  and  what  has  cut  off 


222  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

that  supply?     The  mere  elevation  of  the  rim  and  depression  of 
the  lake  basin  (§  614)  would  not  cut  it  off. 

616.  If  we  establish  the  fact  that  the  Dead  Sea  at  a  former  pe- 
riod did  send  a  river  to  the  ocean,  we  carry  along  with  this  fact  the 
admission  that  when  that  sea  overflowed  into  that  river,  then  the 
water  that  fell  from  the  clouds  over  the  Dead  Sea  basin  was  more 
than  the  winds  could  convert  into  vapor  and  carry  away  again  ; 
the  river  carried  off  the  excess  to  the  ocean  whence  it  came  (§  165). 

617.  In  the  basin  of  the  Dead  Sea,  in  the  basin  of  the  Caspian, 
of  the  Sea  of  Aral,  and  in  the  other  inland  basins  of  Asia,  w^e  are 
entitled  to  infer  that  the  precipitation  and  evaporation  are  at  this 
time  exactly  equal.  Were  it  not  so,  the  level  of  these  seas^  would 
be  rising  or  sinking.  If  the  precipitation  were  in  excess,  these 
seas  would  be  gradually  becoming  fuller ;  and  if  the  evaporation 
were  in  excess,  they  would  be  gradually  drying  up ;  but  observa- 
tion does  not  show,  nor  history  tell  us,  that  either  is  the  case.  As 
far  as  we  know,  the  level  of  these  seas  is  as  permanent  as  that  of 
the  ocean,  and  it  is  difficult  to  realize  the  existence  of  subterrane- 
an channels  between  them  and  the  great  ocean.  Were  there  such 
a  channel,  the  Dead  Sea  being  the  lower,  it  would  be  the  recipi- 
ent of  ocean  waters  ;  and  we  can  not  conceive  how  it  should  be 
such  a  recipient  without  ultimately  rising  to  the  level  of  its  feeder. 

618.  It  may  be  that  the  question  suggested  by  my  researches 
has  no  bearing  upon  the  Dead  Sea ;  that  local  elevations  and  sub- 
sidences alone  were  concerned  in  placing  the  level  of  its  waters 
where  it  is.  But  is  it  probable  that,  throughout  all  the  geological 
periods,  during  all  the  changes  that  have  taken  place  in  the  dis- 
tribution of  land  and  water  surface  over  the  earth,  the  winds, 
which  in  the  general  channels  of  circulation  pass  over  the  Dead 
Sea,  have  alone  been  unchanged  ?  Throughout  all  ages,  periods, 
and  formations,  is  it  probable  that  the  winds  have  brought  us  just 
as  much  moisture  to  that  sea  as  they  now  bring,  and  have  just 
taken  up  as  much  water  from  it  as  they  now  carry  off?  Obvi- 
ously and  clearly  not.  The  salt-beds,  the  water-marks,  the  geo- 
logical formations,  and  other  facts  traced  by  Nature's  own  hand 
upon  the  tablets  of  the  rock,  all  indicate  plainly  enough  that  not 
only  the  Dead  Sea,  but  the  Caspian  also,  had  upon  them,  in  for- 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  223 

mer  periods,  more  abundant  rains  than  they  now  have.  Where 
did  the  vapor  for  those  rains  come  from  ?  and  what  has  stopped 
the  supply  ?  Surely  not  the  elevation  or  depression  of  the  Dead 
Sea  basin. 

619.  My  reasearches  with  regard  to  the  winds  have  suggested 
the  probability  (§  172)  that  the  vapor  which  is  condensed  into 
rains  for  the  lake  valley,  and  whicli  the  St.  Lawrence  carries  off 
to  the  xltlantic  Ocean,  is  taken  up  by  the  southeast  trade-winds 
of  the  Pacific  Ocean.  Suppose  this  to  be  the  case,  and  that  the 
winds  which  bring  this  vapor  arrive  with  it  in  the  lake  country  at 
a  mean  dew-point  of  50°.  This  would  make  the  southwest  winds 
the  rain  winds  for  the  lakes  generally,  as  well  as  for  the  ]\Iissis- 
sippi  Valley ;  they  are  also,  speaking  generally,  the  rain  winds  of 
Europe,  and,  I  have  no  doubt,  of  extra-tropical  Asia  also. 

620.  Now  suppose  a  certain  mountain  range,  hundreds  of  miles 
to  the  southwest  of  the  lakes,  but  across  the  path  of  these  winds, 
were  to  be  suddenly  elevated,  and  its  crest  pushed  into  the  regions 
of  snow,  having  a  mean  temperature  at  its  summit  of  30°  Fah- 
renheit. The  winds,  in  passing  that  range,  would  be  subjected 
to  a  mean  dew-point  of  30°  ;  and,  not  meeting  (§  196)  with  any 
more  evaporating  surface  between  such  range  and  the  lakes,  they 
would  have  no  longer  any  moisture  to  deposit  at  the  supposed  lake 
temperature  of  50° ;  for  they  could  not  yield  their  moisture  to  any 
thing  above  30°.  Consequently,  the  amount  of  precipitation  in  the 
lake  country  would  fall  off ;  the  winds  which  feed  the  lakes  would 
cease  to  bring  as  much  water  as  the  lakes  now  give  to  the  St. 
Lawrence.  In  such  a  case,  that  river  and  the  Niagara  would  drain 
them  to  the  level  of  their  bed ;  evaporation  would  be  increased  by 
reason  of  the  dryness  of  the  atmosphere  and  the  want  of  rain,  and 
the  lakes  would  sink  to  that  level  at  which,  as  in  the  case  of  the 
Caspian  Sea,  the  precipitation  and  evaporation  would  finally  be- 
come equal. 

621.  There  is  a  self-regulating  principle  that  would  bring  about 
this  equality ;  for  as  the  water  in  the  lakes  becomes  lower,  the 
area  of  its  surface  would  be  diminished,  and  the  amount  of  vapor 
taken  from  it  would  consequently  become  less  and  less  as  the  sur- 
face was  lowered,  until  the  amount  of  water  evaporated  would  be- 


224       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

come  equal  to  the  amount  rained  down  again,  precisely  in  the 
same  way  that  the  amount  of  water  evaporated  from  the  sea  is  ex- 
actly equal  to  the  whole  amount  poured  back  into  it  by  the  rains, 
the  fogs,  and  the  dews.*  Thus  the  great  lakes  of  this  continent 
would  remain  inland  seas  at  a  permanent  level ;  the  salt  brought 
from  the  soil  by  the  washings  of  the  rivers  and  rains  would  cease 
to  be  taken  off  to  the  ocean  as  it  now  is ;  and  finally,  too,  the 
great  American  lakes,  in  the  process  of  ages,  w^ould  become  first 
brackish,  and  then  briny. 

622.  Now  suppose  the  water  basins  which  hold  the  lakes  to  be 
over  a  thousand  fathoms  (six  thousand  feet)  deep.  We  know 
tkey  are  not  more  than  four  hundred  and  twenty  feet  deep ;  but 
suppose  them  to  be  six  thousand  feet  deep.  The  process  of  evap- 
oration, after  the  St.  Lawrence  had  gone  dry,  might  go  on  until 
one  or  two  thousand  feet  or  more  were  lost  from  the  surface,  and 
we  should  then  have  another  instance  of  the  level  of  an  inland 
water-basin  being  far  below  the  sea-level,  as  in  the  case  of  the 
Dead  Sea ;  or  it  would  become  a  rainless  district,  when  the  lakes 
themselves  would  go  dry. 

623.  Or  let  us  take  another  case  for  illustration.  Corallines 
are  at  work  about  the  Gulf  Stream ;  they  have  built  up  the  Flor- 
ida Reefs  on  one  side,  and  the  Bahama  Banks  on  the  other.  Sup- 
pose they  should  build  up  a  dam  across  the  Florida  Pass,  and  ob- 
struct the  Gulf  Stream ;  and  that,  in  like  manner,  they  were  to 
connect  Cuba  with  Yucatan  by  damming  up  tlie  Yucatan  Pass,  so 
that  the  waters  of  the  Atlantic  should  cease  to  flow  into  the  Gulf 
of  Mexico.     What  should  we  have  ? 

624.  The  depth  of  the  marine  basin  which  holds  the  waters  of 
that  Gulf  is,  in  the  deepest  part,  about  three  quarters  of  a  mile. 
The  officers  of  the  United  States  ship  Albany  have  run  a  line  of 
deep-sea  soundings  from  west  to  east  across  the  Gulf;  the  great- 
est depth  they  reported  was  about  six  thousand  feet.  Subsequent 
experiments,  however,  induce  the  belief  that  the  dejDth  is  not  quite 
so  great. 

625.  We  should  therefore  have,  by  stopping  up  the  channels 
between  the  Gulf  and  the  Atlantic,  not  a  sea-level  in  the  Gulf,  but 

*  The  quantity  of  dew  in  England  is  about  five  inches  during  a  year. — Glaisher. 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  225 

we  should  have  a  mean  level  between  evaporation  and  precipita- 
tion. If  the  former  were  in  excess,  the  level  of  the  Gulf  waters 
would  sink  down  until  the  surface  exposed  to  the  air  Avould  be  just 
sufficient  to  return  to  the  atmosphere,  as  vapor,  the  amount  of 
water  discharged  by  the  rivers — the  Mississippi  and  others,  into 
the  Gulf.  As  the  waters  were  lowered,  the  extent  of  evaporating 
surface  would  grow  less  and  less,  until  Nature  should  establish 
the  proper  ratio  between  the  ability  of  the  air  to  take  up  and  the 
capacity  of  the  clouds  to  let  down.  Thus  we  might  have  a  sea 
whose  level  would  be  much  farther  below  the  water-level  of  the 
ocean  than  is  the  Dead  Sea. 

626.  There  is  still  anotlier  process,  besides  the  two  already  al- 
luded to,  by  which  the  drainage  of  these  inland  basins  may,  through 
the  agency  of  the  winds,  have  been  cut  off  from  the  great  salt  seas, 
and  that  is  by  the  elevation  of  continents  from  the  bottom  of  the 
sea  in  distant  regions  of  the  earth,  and  the  substitution  caused 
thereby  of  dry  land  instead  of  water  for  the  winds  to  blow  upon. 

627.  Now  suppose  that  a  continent  should  rise  up  in  that  part 
of  the  ocean,  wherever  it  may  be,  that  supplies  the  clouds  with  the 
vapor  that  makes  the  rain  for  the  hydrographic  basin  of  the  great 
American  lakes.  What  w^ould  be  the  result  ?  Why,  surely,  few- 
er clouds  and  less  rain,  which  would  involve  a  change  of  climate 
in  the  lake  country ;  an  increase  of  evaporation  from  it,  because  a 
decrease  of  precipitation  upon  it ;  and,  consequently,  a  diminution 
of  cloudy  screens  to  protect  the  waters  of  the  lakes  from  being 
sucked  up  by  the  rays  of  the  sun ;  and  consequently,  too,  there 
would  follow  a  low  stage  for  water-courses,  and  a  lowering  of  the 
lake-level  would  ensue. 

628.  So  far,  I  have  instanced  these  cases  only  hypothetically ; 
but,  both  in  regard  to  the  hydrographical  basins  of  the  ]\rexican 
Gulf  and  American  lakes,  I  have  confined  myself  strictly  to  anal- 
ogies. Ijilountain  ranges  have  been  upheaved  across  the  course  of 
the  winds,  and  continents  have  been  raised  from  the  bottom  of  the 
sea ;  and,  no  doubt,  the  influence  of  such  upheavals  has  been  felt 
in  remote  regions  by  means  of  the  winds,  and  the  effects  which  a 
greater  or  less  amount  of  moisture  brought  by  them  would  produce. 

629.  In  the  case  of  the  Salt  Lake  of  Utah,  we  have  an  example 


226  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

of  drainage  that  has  been  cut  off,  and  an  illustration  of  the  process 
by  which  Nature  equalizes  the  evaporation  and  precipitation.  To 
do  this,  in  this  instance,  she  is  salting  up  the  basin  which  received 
the  drainage  of  this  inland  water-shed.  Here  we  have  the  appear- 
ance, I  am  told,  of  an  old  channel  by  -which  the  water  used  to  flow 
from  this  basin  to  the  sea.  Supposing  there  was  such  a  time  and 
such  a  water-course,  the  water  returned  through  it  to  the  ocean 
was  the  amount  by  which  the  precipitation  used  to  exceed  the 
evaporation  over  the  whole  extent  of  country  drained  through  this 
now  dry  bed  of  a  river.  The  winds  have  had  something  to  do 
with  this  ;  they  are  the  agents  which  used  to  bring  more  moist- 
ure from  the  sea  to  this  water-shed  than  they  carried  away ;  and 
they  are  the  agents  which  now  carry  off  from  that  valley  more 
moisture  than  is  brought  to  it,  and  which,  therefore,  are  making 
a  salt-bed  of  places  that  used  to  be  covered  by  water.  In  like 
manner,  there  is  evidence  that  the  great  American  lakes  formerly 
had  a  drainage  with  the  Gulf  of  Mexico  ;  for  boats  or  canoes  have 
been  actually  known,  in  former  years,  and  in  times  of  freshets,  to 
pass  from  the  Mississippi  River  over  into  the  lakes.  At  low  wa- 
ter, the  bed  of  a  dry  river  can  be  traced  between  them.  Now  the 
Salt  Lake  of  Utah  is  to  the  southward  and  westward  of  our  north- 
ern lake  basin  ;  that  is  the  quarter  (§  364)  whence  the  rain-winds 
have  been  supposed  to  come.  May  not  the  same  cause  which 
lessened  the  precipitation  or  increased  the  evaporation  in  the  Salt 
Lake  water-shed,  have  done  the  same  for  the  water-shed  of  the 
great  American  system  of  lakes  ? 

630.  If  the  mountains  to  the  west — the  Sierra  Nevada,  for  in- 
stance— stand  higher  now  than  they  formerly  did,  and  if  the  winds 
which  fed  the  Salt  Lake  valley  with  precipitation  had,  as  (§  361) 
I  suppose  they  have,  to  pass  the  summits  of  the  mountains,  it  is 
easy  to  perceive  why  the  winds  should  not  convey  as  much  vapor 
across  them  now  as  they  did  when  the  summit  of  the  range  was 
lower  and  not  so  cool. 

631.  The  Andes,  in  the  trade-wind  region  of  South  America, 
stand  up  so  high,  that  the  wind,  in  order  to  cross  them,  has  to 
part  with  all  its  moisture  (§  196),  and  consequently  there  is,  on 
the  west  side,  a  rainless  region.     Now  suppose  a  range  of  such 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  227 

mountains  as  these  to  be  elevated  across  the  track  of  the  winds 
which  supply  the  lake  country  with  rains ;  it  is  easy  to  perceive 
how  the  whole  country  to  the  leeward  of  such  range,  and  now  wa- 
tered by  the  vapor  which  such  winds  bring,  would  be  converted 
into  a  rainless  region. 

632.  I  have  used  these  hypothetical  cases  to  illustrate  a  posi- 
tion which  any  philosopher,  who  considers  the  geological  agency 
of  the  winds,  may  with  propriety  consult,  when  he  is  told  of  an 
inland  basin  the  water-level  of  which,  it  is  evident,  was  once  high- 
er than  it  now  is  ;  and  that  position  is  that,  though  the  evidences 
of  a  higher  water-level  be  unmistakable  and  conclusive,  it  does  not 
follow,  therefore,  that  there  has  been  a  subsidence  of  the  lake  basin 
itself,  or  an  upheaval  of  the  water-shed  drained  by  it. 

633.  The  cause  which  has  produced  this  change  in  the  water- 
level,  instead  of  being  local  and  near,  may  be  remote ;  it  may 
have  its  seat  in  the  obstructions  to  "the  wind  in  his  circuits," 
which  have  been  interposed  in  some  other  quarter  of  the  world, 
which  obstructions  may  prevent  the  winds  from  taking  up  or  from 
bearing  off  their  wonted  supplies  of  moisture  for  the  region  whose 
water-level  has  been  lowered. 

634.  Having  therefore,  I  hope,  made  clear  the  meaning  of  the 
question  proposed,  by  showing  the  manner  in  which  winds  may 
become  important  geological  agents,  and  having  explained  how 
the  upheaving  of  a  mountain  range  in  one  part  of  the  world  may, 
through  the  winds,  bear  upon  the  physical  geography  of  the  sea, 
affect  climates,  and  produce  geological  phenomena  in  another,  I 
return  to  the  Dead  Sea  and  the  great  inland  basins  of  Asia,  and 
ask.  How  far  is  it  possible  for  the  elevation  of  the  South  American 
continent,  and  the  upheaval  of  its  mountains,  to  have  had  any  ef- 
fect upon  the  water-level  of  those  seas  ?  There  are  indications 
(§  618)  that  they  all  once  had  a  higher  water-level  than  they  now 
have,  and  that  formerly  the  amount  of  precipitation  was  greater 
than  it  now  is ;  then  what  has  become  of  the  sources  of  vapor  ? 
What  has  diminished  its  supply?  Its  supply  would  be  dimin- 
ished (§  627)  either  by  the  substitution  of  dry  land  for  water-sur- 
face in  those  parts  of  the  ocean  which  used  to  supply  that  vapor ; 
or  the  quantity  of  vapor  deposited  in  the  hydrographical  basins  of 

P 


228  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

those  seas  would  have  been  lessened  if  a  snow-capped  range  of 
mountains  (§  620)  had  been  elevated  across  the  path  of  these 
winds,  between  the  places  where  they  were  supplied  with  vapor 
and  these  basins. 

635.  A  chain  of  evidence  which,  it  would  be  difficult  to  set 
aside  is  contained  in  the  chapters  beginning  severally  at  p.  70,  125, 
and  209,  going  to  show  that  the  vapor  which  supplies  the  extra- 
tropical  regions  of  the  north  with  rains  comes,  in  all  probability, 
from  the  trade-wind  regions  of  the  southern  hemisphere. 

636.  Now  if  it  be  true  that  the  trade-winds  from  that  part  of 
the  world  take  up  there  the  water  which  is  to  be  rained  in  the 
extra-tropical  nortli,  the  path  ascribed  to  the  southeast  trades  of 
Africa  and  America,  after  they  descend  and  become  the  prevailing 
southwest  winds  of  the  northern  hemisphere,  should  pass  over  a 
region  of  less  precipitation  generally  than  they  would  do  if,  while 
perfomiing  the  office  of  southeast  trades,  they  had  blown  over  wa- 
ter instead  of  land.  The  southeast  trade-winds,  with  their  load 
of  vapor,  whether  great  or  small,  take,  after  ascending  in  the  equa- 
torial calms,  a  northeasterly  direction ;  they  continue  to  flow  in 
the  upper  regions  of  the  air  in  that  direction  until  they  cross  the 
tropic  of  Cancer.  Tlie  places  of  least  rain,  then,  between  this 
tropic  and  the  pole,  should  be  precisely  those  places  which  depend 
for  their  rains  upon  the  vapor  which  the  winds  that  blow  over 
southeast  trade- wind  Africa  and  America  convey. 

637.  Now,  if  we  could  trace  the  path  of  the  winds  through  the 
extra-tropical  regions  of  the  northern  hemisphere,  we  should  be 
able  to  identify  the  track  of  these  Andean  winds  by  the  foot-prints 
of  the  clouds ;  for  the  path  of  the  winds  which  depend  for  their 
moisture  upon  such  sources  of  supply  as  the  dry  land  of  Central 
South  America  and  Africa  can  not  lie  through  a  country  that  is 
watered  well. 

638.  It  is  a  remarkable  coincidence,  at  least,  that  the  countries 
in  the  extra-tropical  regions  of  the  north  that  are  situated  to  the 
northeast  of  the  southeast  trade-winds  of  South  Africa  and  Amer- 
ica— that  these  countries,  over  which  theory  makes  these  winds 
to  blow,  include  all  the  great  deserts  of  Asia,  and  the  districts  of 
least  precipitation  in  Europe.     A  line  from  the  Galapagos  Islands 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  229 

througli  Florence  in  Italy,  another  from  the  mouth  of  the  Amazon 
through  Aleppo  in  Holy  Land  (Plate  VII.),  would,  after  passing 
the  tropic  of  Cancer,  mark  upon  the  surface  of  the  earth  the  route 
of  these  winds;  this  is  that  "lee  country"  (§  200)  which,  if  such 
he  the  system  of  atmospherical  circulation,  ought  to  be  scantily 
supplied  with  rains.  Now  the  hyetographic  map  of  Europe,  in 
Johnston's  beautiful  Physical  Atlas,  places  the  region  of  least 
precipitation  between  these  two  lines  (Plate  YIL). 

639.  It  would  seem  that  Nature,  as  if  to  reclaim  this  "lee" 
land  fi'om  the  desert,  had  stationed  by  the  way-side  of  these  winds 
a  succession  of  inland  seas,  to  serve  them  as  relays  for  supplying 
them  with  moisture.  There  is  the  Mediterranean,  with  its  arms, 
the  Caspian  Sea,  and  the  Sea  of  Aral,  all  of  which  are  situated 
exactly  in  this  direction,  as  though  these  sheets  of  water  were  de- 
signed, in  the  grand  system  of  aqueous  arrangements,  to  supply 
with  fresh  vapor,  winds  that  had  already  left  rain  enough  behind 
them  to  make  an  Amazon  and  an  Oronoco  of. 

640.  Now  that  there  has  been  such  an  elevation  of  land  out  of 
the  water,  we  infer  from  the  fact  that  the  Andes  were  once  cov- 
ered by  the  sea,  for  their  tops  are  now  crowned  with  the  remains 
of  marine  animals.  When  they  and  their  continent  were  sub- 
merged— admitting  that  Europe  in  general  outline  was  then  as  it 
now  is^it  can  not  be  supposed,  if  the  circulation  of  vapor  were 
then  such  as  it  is  supposed  now  to  be,  that  the  climates  of  that 
part  of  the  Old  World  which  is  under  the  lee  of  those  mountains 
were  then  as  scantily  supplied  with  moisture  as  they  now  are. 
When  the  sea  covered  South  America,  the  winds  had  nearly  all 
the  waters  which  now  make  the  Amazon  to  bring  away  with  them, 
and  to  distribute  among  the  countries  situated  along  the  route 
(Plate  yil.)  ascribed  to  them. 

641.  If  ever  the  Caspian  Sea  exposed  a  larger  surface  for  evap- 
oration than  it  now  does — and  no  doubt  it  did ;  if  the  precipita- 
tion in  that  valley  ever  exceeded  the  evaporation  from  it,  as  it 
does  in  all  valleys  drained  into  the  open  sea,  tlien  there  must  have 
been  a  change  of  hygrometrical  conditions  there.  And  admitting 
the  vapor-springs  for  that  valley  to  be  situated  in  the  direction 
supposed,  the  rising  up  of  a  continent  from  the  bottom  of  the  sea. 


230  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

or  the  upheaval  of  a  range  of  mountains  in  certain  parts  of  Amer- 
ica, Africa,  or  Spain,  across  the  route  of  the  winds  which  brought 
the  rain  for  the  Caspian  water-shed,  might  have  been  sufficient  to 
rob  them  of  the  moisture  which  they  were  wont  to  carry  away 
and  precipitate  upon  this  great  inland  basin.  See  how  the  Andes 
have  made  Atacama  a  desert,  and  of  Western  Peru  a  rainless 
country;  these  regions  have  been  made  rainless  simply  by  the 
rising  up  of  a  mountain  range  between  them  and  the  vapor-springs 
in  the  ocean  which  feed  with  moisture  the  winds  that  blow  over 
those  now  rainless  regions. 

642.  That  part  of  Asia,  then,  which  is  under  the  lee  of  south- 
ern trade-wind  Africa,  lies  to  the  north  of  the  tropic  of  Cancer, 
and  between  two  lines,  the  one  passing  through  Cape  Palmas  and 
Medina,  the  other  through  Aden  and  Delhi.  Being  extended  to 
the  equator,  they  will  include  that  part  of  it  which  is  crossed  by 
the  continental  southeast  trade-winds  of  Africa,  after  they  have 
traversed  the  greatest  extent  of  land  surface  (Plate  YII.). 

643.  The  range  which  lies  between  the  two  lines  that  represent 
the  course  of  the  American  winds  with  their  vapors,  and  the  two 
lines  which  represent  the  course  of  the  African  winds  with  their 
vapors,  is  the  range  which  is  under  the  lee  of  winds  that  have,  for 
the  most  part,  traversed  water-surface,  or  the  ocean,  in  their  cir- 
cuit as  southeast  trade-winds.  But  a  bare  inspection  of  Plate  YII. 
will  show  that  the  southeast  trade-winds  which  cross  the  equator 
between  longitude  15°  and  50°  west,  and  which  are  supposed  to 
blow  over  into  this  hemisphere  between  these  two  ranges,  have 
traversed  land  as  well  as  water ;  and  the  Trade-wind  Chart*  shows 
that  it  is  precisely  those  winds  which,  in  the  summer  and  fall,  are 
converted  into  southwest  monsoons  for  supplying  the  whole  ex- 
tent of  Guinea  with  rains  to  make  rivers  of.  Those  winds,  there- 
fore, it  would  seem,  leave  much  of  their  moisture  behind  them,  and 
pass  along  to  their  channels  in  the  grand  system  of  circulation,  for 
the  most  part,  as  dry  winds.  Moreover,  it  is  not  to  be  supposed 
that  the  channels  through  which  the  winds  blow  that  cross  the 
equator  at  the  several  places  named  are  as  sharply  defined  in  nature 
as  the  lines  suggested,  or  as  Plate  VII.,  would  represent  them  to  be. 

*  Series  of  Maury's  Wind  and  Current  Charts. 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  231 

644.  The  whole  region  of  the  extra-tropical  Old  World  that  is 
included  within  the  ranges  marked,  is  the  region  which  has  most 
land  to  windward  of  it  in  the  southern  hemisphere.  Now  it  is  a 
curious  coincidence,  at  least,  that  all  the  great  extra-tropical  des- 
erts of  the  earth,  with  those  regions  in  Europe  and  Asia  which 
have  the  least  amount  of  precipitation  upon  them,  should  lie  with- 
in this  range.  That  they  are  situated  under  the  lee  of  the  south- 
ern continents,  and  have  but  little  rain,  may  be  a  coincidence,  I 
admit ;  but  that  these  deserts  of  the  Old  World  are  placed  where 
they  are  is  no  coincidence — no  accident :  they  are  placed  where 
they  are,  and  as  they  are,  by  design ;  and  in  being  so  placed,  it  was 
intended  that  they  should  subserve  some  grand  purpose  in  the  ter- 
restrial economy.  Let  us  see,  therefore,  if  we  can  discover  any 
other  marks  of  that  design — any  of  the  purposes  to  be  subserved 
by  such  an  arrangement — and  trace  any  connection  between  that 
arrangement  and  the  supposition  which  I  maintain  as  to  the  place 
where  the  winds  that  blow  over  these  regions  derive  their  vapors. 

645.  It  will  be  remarked  at  once  that  all  the  inland  seas  of 
Asia,  and  all  those  of  Europe  except  the  semi-fresh-water  gulfs  of 
the  north,  are  within  this  range.  The  Persian  Gulf  and  the  Eed 
Sea,  the  Mediterranean,  the  Black,  and  the  Caspian,  all  fall  within. 
it.  And  why  are  they  planted  there  ?  Why  are  they  arranged 
to  the  northeast  and  southwest  under  this  lee,  and  in  the  very  di- 
rection in  which  theory  makes  this  breadth  of  thirsty  winds  to 
prevail  ?  Clearly  and  obviously,  one  of  the  purposes  in  the  di- 
vine economy  was,  that  they  might  replenish  with  vapor  the  winds 
which  are  almost  vaporless  when  they  arrive  at  these  regions  in 
the  general  system  of  circulation.  And  why  should  these  winds 
be  almost  vaporless  ?  They  are  almost  vaporless  because  their 
route,  in  the  general  system  of  circulation,  is  such,  that  they  are 
not  brought  into  contact  with  a  water-surface  from  which  the 
needful  supplies  of  vapor  are  to  be  had ;  or,  being  obtained,  the 
supplies  have  since  been  taken  away  by  the  cool  tops  of  mountain 
ranges  over  which  these  winds  have  had  to  pass. 

646.  In  the  Mediterranean,  the  evaporation  is  greater  than  the 
precipitation.  Upon  the  Eed  Sea  there  never  falls  a  drop  of  rain ; 
it  is  all  evaporation.     Are  we  not,  therefore,  entitled  to  regard  the 


232       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

Red  Sea  as  a  make-weiglit,  thrown  in  to  regulate  the  proportion 
of  clotid  and  sunshine,  and  to  dispense  rain  to  certain  parts  of  the 
earth  in  due  season  and  in  proper  quantities  ?  Have  we  not,  in 
these  two  facts,  evidence  conclusive  that  the  winds  which  blow  over 
these  two  seas  come,  for  the  most  part,  from  a  dry  country — from 
regions  which  contain  few  or  no  pools  to  furnish  supplies  of  vapor? 

647.  Indeed,  so  scantily  supplied  with  vapor  are  the  winds 
which  pass  in  the  general  channels  of  circulation  over  the  water- 
shed and  sea-basin  of  the  Mediterranean,  that  they  take  up  there 
more  water  as  vapor  than  they  deposit.  But,  throwing  out  of  the 
question  what  is  taken  up  from  the  surface  of  the  Mediterranean 
itself,  these  winds  deposit  more  water  on  the  water-shed  whose 
drainage  leads  into  that  sea  than  they  take  up  from  it  again.  The 
excess  is  to  be  found  in  the  rivers  which  discharge  themselves  into 
the  ^lediterranean ;  but  so  thirsty  are  the  winds  which  blow  across 
the  bosom  of  that  sea,  that  they  not  only  take  up  again  all  the 
water  that  those  rivers  pour  into  it,  but  they  are  supposed  by 
philosophers  to  create  a  demand  for  an  immense  current  from  the 
Atlantic  to  supply  the  waste. 

648.  It  is  estimated  that  three*  times  as  much  water  as  the 
Mediterranean  receives  from  its  rivers  is  evaporated  from  its  sur- 
face. This  may  be  an  over-estimate,  but  the  fact  that  evapora- 
tion from  it  is  in  excess  of  the  precipitation,  is  made  obvious  by 
the  current  which  the  Atlantic  sends  into  it  through  the  Straits 
of  Gibraltar ;  and  the  difference,  we  may  rest  assured,  whether  it 
be  much  or  little,  is  carried  off  to  modify  climate  elsewhere — to  re- 
fresh with  showers  and  make  fruitful  some  other  parts  of  the  earth. 

649.  The  great  inland  basin  of  Asia,  in  which  are  Aral  and  the 
Caspian  Seas,  is  situated  on  the  route  which  this  hypothesis  re- 
quires these  thirsty  winds  from  southeast  trade-wind  Africa  and 
America  to  take  ;  and  so  scant  of  vapor  are  these  winds  when 
they  arrive  in  this  basin,  that  they  have  no  moisture  to  leave  be- 
hind ;  just  as  much  as  they  pour  down  they  take  up  again  and 
carry  off.  We  know  (§  166)  that  the  volume  of  water  returned 
by  the  rivers,  the  rains,  and  the  dews,  into  the  whole  ocean,  is  ex- 
actly equal  to  the  volume  which  the  whole  ocean  gives  back  to 

*  Vide  article  *'  Physical  Geography,"  Encyclopsedia  Britannica. 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  233 

the  atmospliere ;  as  far  as  our  knowledge  extends,  the  level  of  each 
of  these  two  seas  is  as  permanent  as  that  of  the  great  ocean  itself. 
Therefore,  the  volume  of  water  discharged  bj  rivers,  the  rains,  and 
the  dews,  into  these  two  seas,  is  exactly  equal  to  the  volume  which 
these  two  seas  give  back  as  vapor  to  the  atmosphere. 

650.  These  winds,  therefore,  do  not  begin  permanently  to  lay 
down  their  load  of  moisture,  be  it  great  or  small,  until  they  cross 
the  Oural  Mountains.  On  the  steppes  of  Issam,  after  they  have 
supplied  the  Amazon  and  the  other  great  equatorial  rivers  of  the 
south,  we  find  them  first  beginning  to  lay  down  more  moisture 
than  they  take  up  again.  In  the  Obi,  the  Yenesi,  and  the  Lena, 
is  to  be  found  the  volume  wdiich  contains  the  expression  for  the 
load  of  water  which  these  winds  have  brought  from  the  southern 
hemisphere,  from  the  Mediterranean,  and  the  Red  Sea;  for  in 
these  almost  hyperborean  river-basins  do  we  find  the  first  instance 
in  wliich,  throughout  the  entire  range  assigned  these  winds,  they 
have,  after  supplying  the  Amazon,  &c.,  left  more  water  behind 
them  than  they  have  taken  up  again  and  carried  off.  The  low 
temperatures  of  Siberian  Asia  are  quite  sufficient  to  extract  from 
these  winds  the  remnants  of  vapor  which  the  cool  mountain-tops 
and  mighty  rivers  of  the  southern  hemisphere  have  left  in  them. 

651.  Here  I  may  be  permitted  to  pause,  that  I  may  call  atten- 
tion to  another  remarkable  coincidence,  and  admire  the  marks  of 
design,  the  beautiful  and  exquisite  adjustments  that  we  see  here 
provided,  to  insure  the  perfect  workings  of  the  great  aqueous  and 
atmospherical  machine.  This  coincidence — may  I  not  call  it  cause 
and  effect? — is  between  the  hygrometrical  conditions  of  all  the 
countries  within,  and  the  hygrometrical  conditions  of  all  the  coun- 
tries without,  the  range  included  within  the  lines  which  I  have 
drawn  (Plate  VII.)  to  represent  the  route  in  the  northern  hemi- 
sphere of  the  southeast  trade-wmds  after  they  have  blown  their 
course  over  the  land  in  South  Africa  and  America.  Both  to  the 
right  and  left  of  this  range  are  countries  included  between  the 
same  parallels  in  which  it  is,  yet  these  countries  all  receive  more 
water  from  the  atmosphere  than  they  give  back  to  it  again ;  they 
all  have  rivers  running  into  the  sea.  On  the  one  hand,  there  is 
in  Europe  the  Ehine,  the  Elbe,  and  all  the  great  rivers  that  empty 


234       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

into  the  Atlantic ;  on  the  other  hand,  there  are  in  Asia  the  Gan- 
ges, and  all  the  great  rivers  of  China ;  and  in  North  America,  in 
the  latitude  of  the  Caspian  Sea,  is  our  great  system  of  fresh-water 
lakes ;  all  of  these  receive  from  the  atmosphere  immense  volumes 
of  water,  and  pour  it  back  into  the  sea  in  streams  the  most  mag- 
nificent. 

652.  It  is  remarkable  that  none  of  these  copiously-supplied 
water-sheds  have,  to  the  southwest  of  them  in  the  trade-wind  re- 
gions of  the  southern  hemisphere,  any  considerable  body  of  land ; 
they  are,  all  of  them,  under  the  lee  of  evaporating  surfaces,  of 
ocean  waters  in  the  trade-wind  regions  of  the  south.  Only  those 
countries  in  the  extra  tropical  north  which  I  have  described  as 
lying  under  the  lee  of  trade-wind  South  America  and  Africa  are 
scantily  supplied  with  rains.  Pray  examine  Plate  YII.  in  this 
connection.     It  tends  to  confirm  the  views  taken  in  Chapter  VI. 

653.  The  surface  of  the  Caspian  Sea  is  about  equal  to  that  of 
our  lakes;  in  it,  evaporation  is  just  equal  to  the  precipitation. 
Our  lakes  are  between  the  same  parallels,  and  about  the  same 
distance  from  the  western  coast  of  America  that  the  Caspian  Sea 
is  from  the  western  coast  of  Europe;  and  yet  the  waters  dis- 
charged by  the  St.  Lawrence  give  us  an  idea  of  how  greatly  the 
precipitation  upon  it  is  in  excess  of  the  evaporation.  To  wind- 
ward of  the  lakes,  and  in  the  trade-wind  regions  of  the  southern 
hemisphere,  is  no  land ;  but  to  windward  of  the  Caspian  Sea,  and 
in  the  trade-wind  region  of  the  southern  hemisphere,  there  is  land. 
Therefore,  supposing  the  course  of  the  vapor-distributing  winds 
to  be  such  as  I  maintain  it  to  be,  ought  they  not  to  carry  more 
water  from  the  ocean  to  the  American  lakes  than  it  is  possible  for 
them  to  carry  from  the  land — from  the  interior  of  South  Africa 
and  America — to  the  valley  of  the  Caspian  Sea  ? 

654.  In  like  manner  (§  393),  extra-tropical  New  Holland  and 
South  Africa  have  each  land — not  water — to  the  windward  of 
them  in  the  trade-mnd  regions  of  the  northern  hemisphere,  where, 
according  to  this  hypothesis,  the  vapor  for  their  rains  ought  to  be 
taken  up :  they  are  both  countries  of  little  rain ;  but  extra-trop- 
ical South  America  has,  in  the  trade-wind  region  to  windward  of 
it  in  the  northern  hemisphere,  a  great  extent  of  ocean,  and  the 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.     235 

amount  of  precipitation  (§  205)  in  extra-tropical  South  America  is 
wonderful.  The  coincidence,  therefore,  is  remarkable,  that  the 
countries  in  the  extra-tropical  regions  of  this  hemisphere,  which  lie 
to  the  northeast  of  large  districts  of  land  in  the  trade-wind  regions 
of  the  other  hemisphere,  should  be  scantily  supplied  with  rains ; 
and  likewise,  that  those  so  situated  in  the  extra-tropical  south, 
with  regard  to  land  in  the  trade-wind  region  of  the  north,  should 
be  scantily  supplied  with  rains. 

655.  Having  thus  remarked  upon  the  coincidence,  let  us  turn 
to  the  evidences  of  design,  and  contemplate  the  beautiful  harmony 
displayed  in  the  arrangement  of  the  land  and  water,  as  we  find 
them  along  this  conjectural  "wind-road."     (Plate  VII.) 

656.  Those  who  admit  design  among  terrestrial  adaptations,  or 
have  studied  the  economy  of  cosmical  arrangements,  will  not  be 
loth  to  grant  that  by  design  the  atmosphere  keeps  in  circulation  a 
certain  amount  of  moisture ;  that  the  water  of  which  this  moist- 
ure is  made  is  supplied  by  the  aqueous  surface  of  the  earth,  and 
that  it  is  to  be  returned  to  the  seas  again  through  rivers  and  the 
process  of  precipitation ;  for  were  it  not  so,  there  would  be  a  per- 
manent increase  or  decrease  of  the  quantity  of  water  thus  put  and 
kept  in  circulation  by  the  y^^inds,  which  would  be  followed  by  a 
corresponding  change  of  hygrometrical  conditions,  which,  in  turn, 
would  draw  after  it  permanent  changes  of  climate  ;  and  permanent 
changes  of  climate  would  involve  the  ultimate  well-being  of  myri- 
ads of  organisms,  both  in  the  vegetable  and  animal  kingdoms. 

657.  The  quantity  of  moisture  that  the  atmosphere  keeps  in 
circulation  is,  no  doubt,  just  that  quantity  which  is  best  suited  to 
the  well-being,  and  most  adapted  to  the  proper  development  of 
the  vegetable  and  animal  kingdoms  ;  and  that  quantity  is  depend- 
ent upon  the  arrangement  and  the  proportions  that  we  see  in  na- 
ture between  the  land  and  the  water — between  mountain  and  des- 
ert, river  and  sea.  If  the  seas  and  evaporating  surfaces  were 
changed,  and  removed  from  the  places  they  occupy  to  other  places, 
the  principal  places  of  precipitation  probably  would  also  be  changed: 
whole  families  of  plants  would  wither  and  die  for  want  of  cloud 
and  sunshine,  dry  and  wet,  in  proper  proportions  and  in  due  sea- 
son ;  and,  with  the  blight  of  plants,  whole  tribes  of  animals  would 


236  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

also  perish.  Under  sucli  a  chance  arrangement,  man  would  no 
longer  be  able  to  rely  upon  the  early  and  the  latter  rain,  or  to 
count  with  certainty  upon  the  rains  being  sent  in  due  season  for 
seed-time  and  harvest.  And  that  the  rain  will  be  sent  in  due 
season,  we  are  assured  from  on  high';  and  when  we  recollect  who 
it  is  that  "  sendeth"  it,  we  feel  the  conviction  strong  within  us — 
that  He  that  sendeth  the  rain  has  the  winds  for  his  messengers ; 
and  that  they  may  do  his  bidding,  the  land  and  the  sea  were  ar- 
ranged, both  as  to  position  and  relative  proportions,  where  they 
are,  and  as  they  are. 

658.  It  should  be  borne  in  mind  that,  by  this  hypothesis,  the 
southeast  trade-winds,  after  they  rise  up  at  the  equator  (Plate  I.), 
have  to  overleap  the  northeast  trade-winds.  Consequently,  they 
do  not  touch  the  earth  until  near  the  tropic  of  Cancer  (see  the  beard- 
ed arrows,  Plate  VII.),  more  frequently  to  the  north  than  to  the 
south  of  it ;  but  for  a  part  of  every  year,  the  place  where  these 
vaulting  southeast  trades  first  strike  the  earth,  after  leaving  the 
other  hemisphere,  is  very  near  this  tropic.  On  the  equatorial  side 
of  it,  be  it  remembered,  the  northeast  trade-winds  blow ;  on  the 
polar  side,  what  were  the  southeast  trades,  and  what  are  now  the 
prevailing  southwesterly  winds  of  our  hemisphere,  prevail.  Now 
examine  Plate  VII.,  and  it  will  be  seen  that  the  upper  half  of  the 
Eed  Sea  is  north  of  the  tropic  of  Cancer ;  the  lower  half  is  to  the 
south  of  it ;  that  the  latter  is  within  the  northeast  trade-wind  re- 
gion ;  the  former,  in  the  region  where  the  southwest  passage  winds 
are  the  prevailing  winds. 

659.  The  River  Tigris  is  probably  evaporated  from  the  upper 
half  of  this  sea  by  these  winds  ;  while  the  northeast  trade-winds 
take  up  from  the  lower  half  those  vapors  which  feed  the  Nile  with 
rain,  and  which  the  clouds  deliver  to  the  cold  demands  of  the 
Mountains  of  the  Moon.  Thus  there  are  two  ' '  wind-roads"  crossing 
this  sea :  to  the  windward  of  it,  each  road  runs  through  a  rainless 
region  ;  to  the  leeward  there  is,  in  each  case,  a  river  rained  down. 

660.  The  Persian  Gulf  lies,  for  the  most  part,  in  the  track  of 
the  southwest  winds ;  to  the  windward  of  the  Persian  Gulf  is  a 
desert ;  to  the  leeward,  the  River  Indus.  This  is  the  route  by 
which  theory  would  require  the  vapor  from  the  Red  Sea  and  Per- 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  237 

siaii'Gnlf  to  be  conveyed,  and  this  is  the  dkection  in  which  we  find 
indications  that  it  is  conveyed.  For  to  leeward  do  we  find,  in  each 
case,  a  river,  telling  to  us,  by  signs  not  to  be  mistaken,  that  it  re- 
ceives more  water  from  the  clouds  than  it  gives  back  to  the  winds. 

661.  Is  it  not  a  curious  circumstance,  that  the  winds  which  trav- 
el the  road  suggested  from  the  southern  hemisphere  should,  when 
they  touch  the  earth  on  the  polar  side  of  the  tropic  of  Cancer,  be 
so  thirsty,  more  thirsty,  much  more,  than  those  which  travel  on 
either  side  of  their  path,  and  which  are  supposed  to  have  come 
fi:om  southern  seas,  not  from  southern  lands  ? 

662.  The  Mediterranean  has  to  give  those  winds  three  times  as 
much  vapor  as  it  receives  from  them  (§  648) ;  the  Bed  Sea  gives 
them  as  much  as  they  can  take,  and  receives  nothing  back  in  re- 
turn but  a  little  dew  (§  407) ;  the  Persian  Gulf  also  gives  more 
than  it  receives.  What  becomes  of  the  rest  ?  Doubtless  it  is 
given  to  the  winds,  that  they  may  bear  it  ofi'to  distant  regions,  and 
make  lands  fruitful,  that  but  for  these  sources  of  supply  would  be 
almost  rainless,  if  not  entirely  arid,  waste,  and  barren. 

663.  These  seas  and  arms  of  the  ocean  now  present  themselves 
to  the  mind  as  counterpoises  in  the  great  hygrometrical  machinery 
of  our  planet. — As  sheets  of  water  placed  where  they  are  to  bal- 
ance the  land  in  the  trade-wind  region  of  South  America  and 
South  Africa,  they  now  present  themselves.  When  the  founda- 
tions of  the  earth  were  laid,  we  know  who  it  was  that  "  measured 
the  waters  in  the  hollow  of  his  hand,  and  meted  out  the  heavens 
with  a  span,  and  comprehended  the  dust  of  the  earth  in  a  meas- 
ure, and  weighed  the  mountains  in  scales,  and  the  hills  in  a  bal- 
ance ;"  and  hence  we  know  also  that  they  are  arranged  both  ac- 
cording to  proportion  and  to  place. 

664.  Here,  then,  we  see  harmony  in  the  winds,  design  in  the 
mountains,  order  in  the  sea,  arrangement  in  the  dust,  and  form  for 
the  desert.  Here  are  signs  of  beauty  and  works  of  grandem' ;  and 
we  may  now  fancy  that,  in  this  exquisite  system  of  adaptations 
and  compensations,  we  can  almost  behold,  in  the  E-ed  and  Medi- 
terranean Seas,  the  very  waters  that  were  held  in  the  hollow  of 
the  Almighty  hand  when  he  weighed  the  Andes  and  balanced  the 
hills  of  Africa  in  the  comprehensive  scales. 


238  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

665.  In  that  great  inland  basin  of  Asia  which  holds  the  Caspian 
Sea,  and  embraces  an  area  of  one  million  and  a  half  of  geograph- 
ical square  miles,  we  see  the  water-surface  so  exquisitely  adjusted 
that  it  is  just  sufficient,  and  no  more,  to  return  to  the  atmosphere 
as  vapor  exactly  as  much  moisture  as  the  atmosphere  lends  in 
rain  to  the  rivers  of  that  basin — a  beautiful  illustration  of  the  fact 
that  the  span  of  the  heavens  was  meted  out  according  to  the 
measure  of  the  waters. 

666.  Thus  we  are  entitled  to  regard  (§  639)  the  Mediterranean, 
the  Eed  Sea,  and  Persian  Gulf  as  relays,  distributed  along  the 
route  of  these  thirsty  winds  from  the  continents  of  the  other  hem- 
isphere, to  supply  them  with  vapors,  or  to  restore  to  them  that 
which  they  have  left  behind  to  feed  the  sources  of  the  Amazon, 
the  Niger,  and  the  Congo. 

667.  The  hypothesis  that  the  winds  from  South  Africa  and 
America  do  take  the  course  through  Europe  and  Asia  which  I  have 
marked  out  for  them  (Plate  YII.),  is  supported  by  so  many  coin- 
cidences, to  say  the  least,  that  we  are  entitled  to  regard  it  as  prob- 
ably correct,  until  a  train  of  coincidences  at  least  as  striking  can 
be  adduced  to  show  that  such  is  not  the  case. 

668.  Returning  once  more  to  a  consideration  of  the  geological 
agency  of  the  winds  in  accounting  for  the  depression  of  the  Dead 
Sea,  we  now  see  the  fact  palpably  brought  out  before  us,  that 
if  the  Straits  of  Gibraltar  were  to  be  barred  up,  so  that  no  water 
could  pass  through  them,  we  should  have  a  great  depression  of  wa- 
ter-level in  the  Mediterranean.  Three  times  as  much  water  (§  648) 
is  evaporated  from  that  sea  as  is  returned  to  it  through  the  rivers. 
A  portion  of  water  evaporated  from  it  is  probably  rained  down  and 
returned  to  it  through  the  rivers ;  but,  supposing  it  to  be  barred 
up — as  the  demand  upon  it  for  vapor  would  exceed  the  supply  by 
rains  and  rivers,  it  would  commence  to  dry  up ;  as  it  sinks  down, 
the  area  exposed  for  evaporation  would  decrease,  and  the  supplies  to 
the  rivers  would  diminish,  until  finally  there  would  be  established 
between  the  evaporation  and  precipitation  an  equilibrium,  as  in  the 
Dead  and  Caspian  Seas.  But,  for  aught  we  know,  the  water-level 
of  the  Mediterranean  might,  before  this  equilibrium  were  attained, 
have  to  reach  a  stage  far  below  that  of  the  Dead  Sea  level. 


ON  THE  GEOLOGICAL  AGENCY  OF  THE  WINDS.  239 

669.  The  Lake  Tacljura  is  now  in  the  act  of  attaining  such  an 
equilibrium.  There  are  connected  with  it  the  remains  of  a  chan- 
nel by  which  the  water  ran  into  the  sea ;  but  the  surface  of  the 
lake  is  now  five  hundred  feet  below  the  sea-level,  and  it  is  salting 
up.  If  not  in  the  Dead  Sea,  do  we  not,  in  the  valley  of  this  lake, 
find  outcropping  some  reason  for  the  question,  What  have  the 
winds  had  to  do  with  the  phenomena  before  us  ? 

670.  The  winds,  in  this  sense,  are  geological  agents  of  great 
power.  It  is  not  impossible  but  that  they  may  afford  us  the 
means  of  comparing,  directly,  geological  events  which  have  taken 
place  in  one  hemisphere,  with  geological  events  in  another :  e,  g., 
the  tops  of  the  Andes  were  once  at  the  bottom  of  the  sea. — Which 
is  the  oldest  formation,  that  of  the  Dead  Sea  or  the  Andes  ?  If 
the  former  be  the  older,  then  the  climate  of  the  Dead  Sea  must 
have  been  hygrometrically  very  different  from  what  it  now  is. 

671.  In  regarding  the  w4nds  as  geological  agents,  we  can  no 
longer  consider  them  as  the  type  of  instability.  We  should  rather 
treat  them  in  the  light  of  ancient  and  faithful  chroniclers,  which, 
upon  being  rightly  consulted,  will  reveal  to  us  truths  that  i^ature 
has  written  upon  their  wings  in  characters  as  legible  and  enduring 
as  any  with  which  she  has  ever  engraved  the  history  of  geological 
events  upon  the  tablet  of  the  rock. 

672.  The  waters  of  Lake  Titicaca,  which  receives  the  drainage 
of  the  great  inland  basin  of  the  Andes,  are  only  brackish,  not  salt. 
Hence  we  may  infer  that  this  Jake  has  not  been  standing  long 
enough  to  become  briny,  like  the  waters  of  the  Dead  Sea ;  conse- 
quently, it  belongs  to  a  more  recent  period.  On  the  other  hand, 
it  will  also  be  interesting  to  hear  that  my  friend.  Captain  Lynch, 
informs  me  that,  in  his  exploration  of  the  Dead  Sea,  he  saw  what 
he  took  to  be  the  dry  bed  of  a  river  that  once  flowed  from  it. 
And  thus  we  have  two  more  links,^  stout  and  strong,  to  add  to  the 
chain  of  circumstantial  evidence  going  to  sustain  the  testimony  of 
this  strange  and  fickle  witness  w^hich  I  have  called  up  from  the 
sea  to  testify  in  this  presence  concerning  the  works  of  Nature, 
and  to  tell  us  which  be  the  older — the  Andes,  watching  the  stars 
with  their  hoary  heads,  or  the  Dead  Sea,  sleeping  upon  its  ancient 
beds  of  crystal  salt. 


240  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTEH  XII. 

THE  DEPTHS  OF  THE  OCEAN. 

Soundings  by  other  Nations,  <J  676. — Contrivances  for  Deep  Soundings,  678. — Clock- 
work, 679.— Torpedo,  680.— Magnetic  Telegraph,  681.— The  Myths  of  the  Sea, 
683. — Attempts  to  Sound,  688. — The  Observatory  Plan  for  Sounding,  690. — Prac- 
tical Difficulties,  692. — Oceanic  Circulation,  695. — Law  of  Plummet's  Descent,  698. 
— Brooke's  Sounding  Apparatus,  700. — Greatest  Depths  yet  reached,  701. — Speci- 
mens from  the  Pacific,  702. 

673.  "We  dive,"  says  Schleiden,*  "into  the  liquid  crystal  of 
the  Indian  Ocean,  and  it  opens  to  us  the  most  wondrous  enchant- 
ments of  the  fairy  tales  of  our  childhood's  dreams.  The  strangely 
branching  thickets  bear  living  flowers.  Dense  masses  of  Mean- 
drinas  and  Astrasas  contrast  with  the  leafy,  cup-shaped  expansions 
of  the  Explanarias,  the  variously-ramified  Madrepores,  which  are 
now  spread  out  like  fingers,  now  rise  in  trunk-like  branches,  and 
now  display  the  most  elegant  array  of  interlacing  branches.  The 
coloring  surpasses  every  thing :  vivid  green  alternates  with  brown 
or  yellow ;  rich  tints  of  purple,  from  pale  red-brown  to  the  deepest 
blue.  Brilliant  rosy,  yellow,  or  peach-colored  NuUipores  overgrow 
the  decaying  masses,  and  are  themselves  interwoven  with  the 
pearl-colored  plates  of  tlie  Retipores,  resembling  the  most  delicate 
ivory  carvings.  Close  by  wave  the  yellow  and  lilac  fans,  perfo- 
rated like  trellis-work,  of  the  Gorgonias.  The  clear  sand  of  the 
bottom  is  covered  with  the  thousand  strange  forms  and  tints  of 
the  sea-urchins  and  star-fishes.  The  leaf-like  Flustras  and  Es- 
charas  adhere  like  mosses  and  lichens  to  the  branches  of  the  cor- 
als ;  the  yellow,  green,  and  purple-striped  Limpets  cling  like  mon- 
strous cochineal  insects  upon  their  trunks.  Like  gigantic  cactus- 
blossoms,  sparkling  in  the  most  ardent  colors,  the  Sea  Anemones 
expand  their  crowns  of  tentacles  upon  the  broken  rocks,  or  more 

*  "The  Plant." 


THE  DEPTHS  OF  THE  OCEAN.  241 

modestly  embellisli  the  flat  bottom,  looking  like  beds  of  variegated 
Ranunculuses.  Around  the  blossoms  of  the  coral  shrubs  play  the 
humming-birds  of  the  ocean,  little  fish  sparkling  with  red  or  blue 
metallic  glitter,  or  gleaming  in  golden  green,  or  in  the  brightest 
silvery  lustre. 

674.  "  Softly,  like  spirits  of  the  deep,  the  delicate  milk-white 
or  bluish  bells  of  the  jelly-fishes  float  through  this  charmed  world. 
Here  the  gleaming  violet  and  gold-green  Isabelle,  and  the  flaming 
yellow,  black,  and  vermilion-striped  Coquette,  chase  their  prey ; 
there  the  band-fish  shoots,  snake-like,  through  the  thicket,  like  a 
long  silver  ribbon,  glittering  with  rosy  and  azure  hues.  Then 
come  the  fabulous  cuttle-fish,  decked  in  all  colors  of  the  rainbow, 
but  marked  by  no  definite  outline,  appearing  and  disappearing,  in- 
tercrossing, joining  company  and  parting  again,  in  most  fantastic 
ways ;  and  all  this  in  the  most  rapid  change,  and  amid  the  most 
wonderful  play  of  light  and  shade,  altered  by  every  breath  of  wind, 
and  every  slight  curling  of  the  surface  of  the  ocean.  When  day 
declines,  and  the  shades  of  night  lay  hold  upon  the  deep,  this  fan- 
tastic garden  is  lighted  up  in  new  splendor.  Millions  of  glowing 
sparks,  little  microscopic  Medusas  and  Crustaceans,  dance  like 
glow-worms  through  the  gloom.  The  sea-feather,  which  by  day- 
light is  vermilion-colored,  waves  in  a  greenish,  phosphorescent 
light.  Every  corner  of  it  is  lustrous.  Parts  which  by  day  were 
perhaps  dull  and  brown,  and  retreated  from  the  sight  amid  the 
universal  brilliancy  of  color,  are  now  radiant  in  the  most  wonder- 
ful play  of  green,  yellow,  and  red  light ;  and  to  complete  the  won- 
ders of  the  enchanted  night,  the  silver  disk,  six  feet  across,  of  the 
moon-fish,*  moves,  slightly  luminous,  among  the  crowd  of  little 
sparkling  stars. 

675.  "  The  most  luxuriant  vegetation  of  a  tropical  landscape 
can  not  unfold  as  great  wealth  of  form,  while  in  the  variety  and 
splendor  of  color  it  would  stand  far  behind  this  garden  landscape, 
which  is  strangely  composed  exclusively  of  animals,  and  not  of 
plants  ;  for,  characteristic  as  the  luxuriant  development  of  vegeta- 
tion of  the  temperate  zones  is  of  the  sea  bottom,  the  fullness  and 
multiplicity  of  the  marine  Fauna  is  just  as  prominent  in  the  re- 

*  Orthagoriscus  mola. 


242  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

gions  of  the  tropics.  Whatever  is  beautiful,  wondrous,  or  uncom- 
mon in  the  great  classes  of  fish  and  Echinoderms,  jelly-fishes  and 
polypes,  and  the  molluscs  of  all  kinds,  is  crowded  into  the  warm 
and  crystal  waters  of  the  tropical  ocean — rests  in  the  white  sands, 
clothes  the  rough  cliifs,  clings,  where'  the  room  is  already  occupied, 
like  a  parasite,  upon  the  first  comers,  or  swims  through  the  shal- 
lows and  depths  of  the  elements — while  the  mass  of  the  vegeta- 
tion is  of  a  far  inferior  magnitude.  It  is  peculiar  in  relation  to 
this,  that  the  law  valid  on  land,  according  to  which  the  animal 
kingdom^  being  better  adapted  to  accommodate  itself  to  outward 
circumstances,  has  a  greater  difiusion  than  the  vegetable  king- 
dom ;  for  the  Polar  seas  swarm  with  whales,  seals,  sea-birds,  fish- 
es, and  countless  numbers  of  the  lower  animals,  even  where  every 
trace  of  vegetation  has  long  vanished  in  the  eternally  frozen  ice, 
and  the  cooled  sea  fosters  no  sea-weed — that  this  law,  I  say,  holds 
good  also  for  the  sea,  in  the  direction  of  its  depth;  for  when  we 
descend,  vegetable  life  vanishes  much  sooner  than  the  animal,  and, 
even  from  the  depths  to  which  no  ray  of  light  is  capable  of  pene- 
trating, the  sounding-lead  brings  up  news  at  least  of  living  infu- 
soria."— Schleiden's  Lectures^  p.  403-406. 

676.  Until  the  commencement  of  the  plan  of  deep-sea  sound- 
ings, as  now  conducted  in  the  American  Navy,  the  bottom  of  what 
the  sailors  call  "blue  water"  was  as  unknown  to  us  as  is  the  in- 
terior of  any  of  the  planets  of  our  system.  Ross  and  Dupetit 
Thouars,  with  other  ofiicers  of  the  English,  French,  and  Dutch  na- 
vies, had  attempted  to  fathom  the  deep  sea,  some  with  silk  threads, 
some  with  spun-yarn  (coarse  hemp  threads  twisted  together),  and 
some  with  the  common  lead  and  line  of  navigation.  All  of  these 
attempts  were  made  upon  the  supposition  that  when  the  lead 
reached  the  bottom,  either  a  shock  would  be  felt,  or  the  line,  be- 
coming slack,  would  cease  to  run  out. 

677.  The  series  of  systematic  experiments  recently  made  upon 
this  subject  shows  that  there  is  no  reliance  to  be  placed  on  such 
a  supposition,  for  the  shock  caused  by  striking  bottom  can  not  be 
communicated  through  very  great  depths.  Furthermore,  the  lights 
of  experience  show  that,  as  a  general  rule,  the  under  currents  of 
the  deep  sea  have  force  enough  to  take  the  line  out  long  after  the 


THE  DEPTHS  OF  THE  OCEAN. 


243 


plummet  has  ceased  to  do  so.  Consequently,  there  is  but  little 
reliance  to  be  placed  upon  deep-sea  soundings  of  former  methods, 
when  the  depths  reported  exceeded  eight  or  ten  thousand  feet. 

678.  Attempts  to  fathom  the  ocean,  both  by  sound  and  press- 
ure, had  been  made,  but  out  in  "  blue  water"  every  trial  was  only  a 
failure  repeated.  The  most  ingenious  and  beautiful  contrivances 
for  deep-sea  soundings  were  resorted  to.  By  exploding  petards, 
or  ringing  bells  in  the  deep  sea,  when  the  winds  were  hushed 
and  all  was  still,  the  echo  or  reverberation  from  the  bottom  might, 
it  was  held,  be  heard,  and  the  depth  determined  from  the  rate  at 
which  sound  travels  through  water.  But,  though  the  concussion 
took  place  many  feet  below  the  surface,  echo  was  silent,  and  no 
answer  was  received  from  the,  bottom.  Ericsson  and  others  con- 
structed deep-sea  leads  having  a  column  of  air  in  them,  which,  by 
compression, would  show  the  aqueous  pressure  to  which  they  might 
be  subjected.  This  was  found  to  answer  well  for  ordinary  pur- 
poses, but  in  the  depths  of  the  sea,  where  the  pressure  would  be 
equal  to  several  hundred  atmospheres,  the  trial  was  more  than  this 
instrument  could  stand. 

679.  Mr.  Baur,  an  ingenious  mechanician  of  New  York,  con- 
structed, according  to  a  j^l^n  which  I  furnished  him,  a  deep-sea 
sounding  apparatus.  To  the  lead  was  attached,  upon  the  princi- 
ple of  the  screw  propeller,  a  small  piece  of  clock-work  for  register- 
ing the  number  of  revolutions  made  by  the  little  screw  during  the 
descent ;  and,  it  having  been  ascertained  by  experiment  in  shoal 
water  that  the  apparatus,  in  descending,  would  cause  the  propeller 
to  make  one  revolution  for  every  fathom  of  perpendicular  descent, 
hands  provided  with  the  power  of  self-registration  were  attached 
to  a  dial,  and  the  instrument  was  complete.  It  worked  beautifully 
in  moderate  depths,  but  failed  in  blue  water,  from  the  difficulty  of 
hauling  it  up  if  the  line  used  were  small,  and  from  the  difficulty 
of  getting  it  down  if  the  line  used  were  large  enough  to  give  the 
requisite  strength  for  hauling  it  up. 

680.  An  old  sea-captain  proposed  a  torpedo,  such  as  is  some- 
times used  in  the  whale  fishery  for  blowing  up  the  monsters  of  the 
deep,  only  this  one  was  intended  to  explode  on  touching  the  bot- 
tom.    It  was  proposed  first  to  ascertain  by  actual  experiment  the 


244  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

rate  at  wliich  the  torpedo  would  sink,  and  the  rate  at  which  the 
sound  or  the  gas  would  ascend,  and  so,  by  timing  the  interval,  to 
determine  the  depth.  This  plan  would  afford  no  specimens  of  the 
bottom,  and  its  adoption  was  opposed  by  other  obstacles. 

681.  One  gentleman  proposed  to  use  the  magnetic  telegraph. 
The  wire,  properly  coated,  was  to  be  laid  up  in  the  sounding-line, 
and  to  the  plummet  was  attached  machinery,  so  contrived  that  at 
the  increase  of  every  100  fathoms,  and  by  means  of  the  additional 
pressure,  the  circuit  would  be  restored,  somewhat  after  the  manner 
of  Dr.  Locke's  electro-chronograph,  and  a  message  would  come  up 
to  tell  how  many  hundred  fathoms  up  and  down  the  plummet  had 
sunk.  As  beautiful  as  this  idea  was,  it  was  not  simple  enough 
in  practical  application  to  answer  our  purposes. 

682.  Greater  difficulties  than  any  presented  by  the  problem  of 
deep-sea  soundings  had  been  overcome  in  other  departments  of 
physical  research.  These  plans  and  attempts  served  to  encour- 
age, nor  were  they  fruitless,  though  they  proved  barren  of  practical 
results.  Astronomers  had  measured  the  volumes  and  weighed 
the  masses  of  the  most  distant  planets,  and  increased  thereby  the 
stock  of  human  knowledge.  Was  it  creditable  to  the  age  that 
the  depths  of  the  sea  should  remain  in  the  category  of  an  unsolved 
problem?  Its  "  ooze  and  bottom"  was  a  sealed  volume,  rich  with 
ancient  and  eloquent  legends,  and  suggestive  of  many  an  instruct- 
ive lesson  that  might  be  useful  and  profitable  to  man.  The  seal 
which  covered  it  was  of  rolling  waves  many  thousand  feet  in 
thickness.  Could  it  not  be  broken  ?  Curiosity  had  always  been 
great,  yet  neither  the  enterprise  nor  the  ingenuity  of  man  had  as 
yet  proved  itself  equal  to  the  task.  No  one  had  succeeded  in  pen- 
etrating, and  bringing  up  from  beyond  the  depth  of  two  or  three 
hundred  fathoms  below  the  aqueous  covering  of  the  earth  any 
specimens  of  solid  matter  for  the  study  of  philosophers. 

683.  The  sea,  with  its  myths,  has  suggested  attractive  themes 
to  all  people  in  all  ages.  Like  the  heavens,  it  affords  an  almost 
endless  variety  of  subjects  for  pleasing  and  profitable  contempla- 
tion, and  there  has  remained  in  the  human  mind  a  longing  to  learn 
more  of  its  wonders  and  to  understand  its  mysteries.  The  Bible 
often  alludes  to  them.     Are  they  past  finding  out  ?     How  deep  is 


THE  DEPTHS  OF  THE  OCEAN.  245 

it  ?  and  what  is  at  the  bottom  of  it  ?     Could  not  the  ingenuity 
and  appliances  of  the  age  throw  some  light  upon  these  questions? 

684.  The  government  was  liberal  and  enlightened  ;  times  seem- 
ed propitious ;  but  when  or  how  to  begin,  after  all  these  failures, 
with  this  interesting  problem,  was  one  of  the  difficulties  first  to  be 
overcome. 

685.  It  was  a  common  opinion,  derived  chiefly  from  a  supposed 
physical  relation,  that  the  depths  of  the  sea  are  about  equal  to  the 
heights  of  the  mountains.  But  this  conjecture  was,  at  best,  only 
a  speculation.  Though  plausible,  it  did  not  satisfy.  There  were, 
in  the  depths  of  the  sea,  untold  wonders  and  inexplicable  myste- 
ries. Therefore  the  contemplative  mariner,  as  in  mid-ocean  he 
looked  down  upon  its  gentle  bosom,  continued  to  experience  sen- 
timents akin  to  those  which  fill  the  mind  of  the  devout  astrono- 
mer when,  in  the  stillness  of  the  night,  he  looks  out  upon  the  stars, 
and  wonders. 

686.  Nevertheless,  the  depths  of  the  sea  still  remained  as  fath- 
omless and  as  mysterious  as  the  firmament  above.  Indeed,  tele- 
scopes of  huge  proportions  and  of  vast  space-penetrating  powers 
had  been  erected  here  and  there  by  the  munificence  of  individuals, 
and  attempts  made  with  them  to  gauge  the  heavens  and  sound  out 
the  regions  of  space.  Could  it  be  more  difficult  to  sound  out  the 
sea  than  to  gauge  the  blue  ether  and  fathom  the  vaults  of  the  sky  ? 
The  result  of  the  astronomical  undertakings*  lies  in  the  discovery 
that  what,  through  other  instruments  of  less  power,  appeared  as 
clusters  of  stars,  were,  by  these  of  larger  powers,  separated  into 
groups,  and  what  had  been  reported  as  nebulae  could  now  be  re- 
solved into  clusters  ;  that,  in  certain  directions,  the  abyss  beyond 
these  faint  objects  is  decked  with  other  nebulas,  which  these  great 
instruments  may  bring  to  light,  but  can  not  resolve ;  and  that  there 
are  still  regions  and  realms  beyond,  which  the  rays  of  the  bright- 
est sun  in  the  sky  have  neither  the  intensity  nor  the  force  to  reach, 
much  less  to  penetrate.  And  what  is  more,  these  monster  instru- 
ments have  revealed  to  us,  in  those  distant  regions,  forms  or  ag- 
gregations of  matter  which  suggest  to  some  the  idea  of  the  exist- 
ence of  physical  forces  there  that  we  do  not  understand,  and  which 

*  See  the  works  of  Herschel  and  Ross,  and  their  telescopes. 


246       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

raise  the  question  in  speculative  minds,  Is  gravitation  a  universal 
thing,  and  do  its  forces  penetrate  every  abyss  of  space  ? 

687.  Could  we  not  gauge  the  sea  as  well  as  the  sky,  and  de- 
vise an  instrument  for  penetrating  the  depths  of  the  ocean  as  well 
as  the  depths  of  space  ?  ]\Iarinerfe  were  curious  concerning  the 
bottom  of  the  sea.  Though  nothing  thence  had  been  brought  to 
light,  exploration  had  invested  the  subject  with  additional  inter- 
est, and  increased  the  desire  to  know  more.  In  this  state  of  the 
case,  the  idea  of  a  common  twine  thread  for  a  sounding-line,  and  a 
cannon  ball  for  a  sinker,  was  suggested.  It  was  a  beautiful  con- 
ception ;  for,  besides  its  simplicity,  it  had  in  its  favor  the  greatest 
of  recommendations — it  could  be  readily  put  into  practice. 

Well-directed  attempts  to  fathom  the  ocean  began  now  to  be 
made  with  such  a  line  and  plummet,  and  the  public  mind  was  as- 
tonished at  the  vast  depths  that  were  at  first  reported. 

688.  Lieutenant  Walsh,  of  the  United  States  schooner  "Taney," 
reported  a  cast  with  the  deep-sea  lead  at  thirty-four  thousand  feet 
without  bottom.  His  sounding-line  was  an  iron  wire  more  than 
eleven  miles  in  length.  Lieutenant  Berryman,  of  the  United 
States  brig  "  Dolphin,"  reported  another  unsuccessful  attempt  to 
fathom  mid-ocean  with  a  line  thirty-nine  thousand  feet  in  length. 
Captain  Denham,  of  her  Britannic  majesty's  ship  "Herald,"  re- 
ported bottom  in  the  South  Atlantic  at  the  depth  of  forty-six 
thousand  feet ;  and  Lieutenant  J.  P.  Parker,  of  the  United  States 
frigate  "Congress,"  afterward,  in  attempting  to  sound  near  the 
same  region,  let  go  his  plummet,  and  saw  it  run  out  a  line  fifty 
thousand  feet  long  as  though  the  bottom  had  not  been  reached. 

689.  The  three  last-named  attempts  were  made  with  the  sound- 
ing twine  of  the  American  Navy,  which  has  been  introduced  in 
conformity  with  a  very  simple  plan  for  sounding  out  the  depths  of 
the  ocean.  It  involved  for  each  cast  only  the  expenditure  of  a 
cannon  ball,  and  twine  enough  to  reach  the  bottom.  This  plan 
was  introduced  as  a  part  of  the  researches  conducted  at  the  Na- 
tional Observatory,  and  which  have  proved  so  fruitful  and  bene- 
ficial, concerning  the  winds  and  currents,  and  other  phenomena 
of  the  ocean.  These  researches  had  already  received  the  appro- 
bation of  the  Congress  of  the  United  States ;  for  that  body,  in  a 


THE  DEPTHS  OF  THE  OCEAN.  247 

spirit  worthy  of  the  representatives  of  a  free  and  enlightened  peo- 
ple, had  authorized  the  Secretary  of  tlie  Navy  to  employ  three 
public  vessels  to  assist  in  perfecting  the  discoveries,  and  in  con- 
ducting the  investigations  connected  therewith. 

690.  The  plan  of  deep-sea  soundings  finally  adopted,  and  now 
in  practice,  is  this  :  Every  vessel  of  the  Navy,  when  she  puts  to 
sea,  is,  if  she  desires  it,  furnished  with  a  sufficient  quantity  of 
sounding-twine,  carefully  marked  at  every  length  of  one  hundred 
fathoms — six  hundred  feet — and  wound  on  reels  of  ten  thousand 
fathoms  each.  It  is  made  the  duty  of  the  commander  to  avail 
himself  of  every  favorable  opportunity  to  try  the  depth  of  the 
ocean,  whenever  he  may  find  himself  out  upon  "blue  water." 
For  this  purpose  he  is  to  use  a  cannon  ball  of  32  or  68  pounds 
as  a  plummet.  Having  one  end  of  the  twine  attached  to  it,  the 
cannon  ball  is  to  be  thrown  overboard  from  a  boat,  and  suffered  to 
take  the  twine  from  the  reel  as  fast  as  it  will. 

691.  The  reel  is  made  to  turn  easily.  A  silk  thread,  or  the  com- 
mon wrapping-twine  of  the  shops  would,  it  was  thouglit,  be  strong 
enough  for  this  purpose ;  for  it  was  supposed  there  would  be  no 
strain  upon  the  line,  except  the  very  slight  one  required  to  drag  it 
down,  and  the  twine  having  nearly  the  specific  gravity  of  sea  wa- 
ter, this  strain  would,  it  was  imagmed,  be  very  slight.  ]\Ioreover, 
when  the  shot  reached  the  bottom,  the  line,  it  was  thought*(§  676), 
would  cease  to  run  out ;  then  breaking  it  off,  and  seeing  how  much 
remained  upon  the  reel,  the  depth  of  the  sea  could  be  ascertained 
at  any  place  and  time,  simply  at  the  expense  of  one  cannon  ball 
and  a  few  pounds  of  common  twine. 

692.  But  practical  difficulties  that  were  not  expected  at  all 
were  lurking  in  the  way,  and  afterward  showed  themselves  at  ev- 
ery attempt  to  sound ;  and  it  was  before  these  practical  difficulties 
had  been  fakly  overcome  that  the  great  soundings  (§  688)  were  re- 
ported. In  the  first  place,  it  was  discovered  that  the  line,  once 
started  and  dragged  down  into  the  depths  of  the  ocean,  never  would 
cease  to  run  out  (§  677),  and,  consequently,  that  there  was  no 
means  of  knowing  when,  if  ever,  the  shot  had  reached  the  bottom. 
And,  in  the  next  place,  it  was  ascertained  that  the  ordinary  twine 
(§  687)  would  not  do ;  that  the  soundinff-line,  in  going  down,  was 


248       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

really  subjected  to  quite  a  heavy  strain,  and  that,  consequently, 
the  t'-.vine  to  be  used  must  be  strong ;  it  was  therefore  subjected 
to  a  test  which  required  it  to  bear  a  weight  of  at  least  sixty  pounds 
freely  suspended  in  the  air.  So  we  had  to  go  to  work  anew,  and 
make  several  hundred  thousand  fathoms  of  sounding-twine  espe- 
cially for  the  purpose.  It  w^as  small,  and  stood  the  test  required, 
a  pound  of  it  measuring  about  six  hundred  feet  in  length. 

693.  The  officers  intrusted  with  the  duty  soon  found  that  the 
soundings  could  not  be  made  from  the  vessel  with  any  certainty 
as  to  the  depth.  It  was  necessary  that  a  boat  should  be  lowered, 
and  the  trial  be  made  from  it ;  the  men  with  their  oars  keeping 
the  boat  from  drifting,  and  maintaining  it  in  such  a  position  that 
the  line  should  be  "up  and  down"  the  while. 

694.  That  the  line  would  continue  to  run  out  after  the  cannon 
ball  had  reached  bottom,  was  explained  by  the  conjecture  that 
there  is  in  the  ocean,  as  in  the  air,  a  system  of  currents  and  coun- 
ter currents  one  above  the  other,  and  that  it  was  one  or  more  of 
these  submarine  currents,  operating  upon  the  bight  of  the  line, 
which  caused  it  to  continue  to  run  out  after  the  shot  had  reached 
the  bottom.  In  corroboration  of  this  conjecture,  it  was  urged, 
with  a  truth-like  force  of  argument,  that  it  was  these  under  cur- 
rents, operating  with  a  swigging  force  upon  the  bights  of  the  line — 
for  there  might  be  several  currents  running  in  different  directions, 
and  operating  upon  it  at  the  same  time — which  caused  it  to  part 
whenever  the  reel  was  stopped  and  the  line  held  fast  in  the  boat. 

695.  A  powerful  train  of  circumstantial  evidence  was  this  (and 
it  was  derived  from  a  source  wholly  unexpected),  going  to  prove 
the  existence  of  that  system  of  oceanic  circulation  which  the  cli- 
mates, and  the  offices,  and  the  adaptations  of  the  sea  require,  and 
which  its  inhabitants  (§  498)  in  their  mute  way  tell  us  of. 

696.  This  system  of  circulation  commenced  on  the  third  day  of 
creation,  with  the  ''gathering  together  of  the  waters,"  which  were 
"called  seas,"  and  doubtless  will  continue  as  long  as  sea  water 
shall  possess  the  properties  of  saltness  and  fluidity. 

697.  In  making  these  deep-sea  soundings,  the  practice  is  to 
time  the  hundred  fathom  marks  as  they  successively  go  out ;  and 
by  always  using  a  line  of  the  same  size  and  "  make,"  and  a  sinker 


THE  DEPTHS  OF  THE  OCEAN.  249 

of  the  same  shape  and  "weight,  we  at  last  established  the  law  of 
descent.  Thus  the  mean  of  our  experiments  gave  us,  for  the 
sinker  and  twine  used, 

2  m.  21  s.  as  the  average  time  of  descent  from    400  to    500  fathoms. 

3  m.  26  s.  "  "  "       1000  to  1100 

4  m.  29  s.  "  "  "       1800  to  1900         " 

698.  Now,  by  aid  of  the  law  here  indicated,  we  could  tell  very 
nearly  when  the  ball  ceased  to  carry  the  line  out,  and  when,  of 
course,  it  began  to  go  out  in  obedience  to  the  current  and  drift 
alone ;  for  currents  would  sweep  the  line  out  at  a  uniform  rate, 
while  the  cannon  ball  would  drag  it  out  at  a  decreasing  rate. 

699.  The  development  of  this  law  was  certainly  an  achieve- 
ment, for  it  enabled  us  to  show  that  the  depth  of  the  sea  at  the 
places  named  (§  688)  was  not  as  great  as  reports  made  it.  These 
researches  were  interesting ;  the  problem  in  hand  was  important, 
and  it  deserved  every  effort  that  ingenuity  could  suggest  for  re- 
ducing it  to  a  satisfactory  solution. 

700.  As  yet,  no  specimens  of  the  bottom  had  been  brought  up. 
The  line  was  too  small,  the  shot  was  too  heavy,  and  it  could  not 
be  weighed,  and  if  we  could  reach  the  bottom,  why  should  we  not 
know  its  character  ?  In  this  state  of  the  case.  Passed  ^Midship- 
man  J.  M.  Brooke,  United  States  Navy,  who,  at  the  time,  was  as- 
sociated with  me  on  duty  at  the  Observatory,  proposed  a  contriv- 
ance by  which  the  shot,  on  striking  the  bottom,  would  detach  it- 
self from  the  line,  and  send  up  a  specimen  of  the  bottom.  This 
beautiful  contrivance,  called  Brooke's  Deep-sea  Sounding  Appara- 
tus, is  represented  in  Plates  II.  and  III.  on  the  next  page. 

A  is  a  cannon  ball,  having  a  hole  through  it  for  the  rod  B. 
Plate  II.  represents  the  rod,  B ;  the  slings,  D  D,  with  the  shot 
slung,  and  in  the  act  of  being  lowered  down.  Plate  III.  repre- 
sents the  apparatus  in  the  act  of  striking  the  bottom,  and  shows 
how  the  shot  is  detached,  and  how  specimens  of  the  bottom  are 
brought  up,  by  adhering  to  a  little  soap  or  tallow,*  called  "arm- 
ing," in  the  cup,  C,  at  the  lower  end  of  the  rod,  B.  With  this 
contrivance  specimens  of  the  bottom  have  been  brought  up  from 
the  depth  of  more  than  two  miles. 

*  The  barrel  of  a  common  quill  attached  to  the  rod  has  been  found  to  answer  better. 


250        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 
PLATE  n.  PLATE  HL 


BROOKE'S  DEEP-SEA  SOUNDING  APPARATUS. 

701.  The  greatest  depths  at  which  the  bottom  of  the  sea  has 
been  reached  with  the  plummet  are  in  the  North  Atlantic  Ocean, 
and  the  places  where  it  has  been  fathomed  do  not  show  it  to  be 
deeper  than  twenty-five  thousand  feet. 

702.  The  deepest  place  in  this  ocean  (Plate  XI.)  is  probably 
between  the  parallels  of  35°  and  40°  north  latitude,  and  immedi- 
ately to  the  southward  of  the  Grand  Banks  of  Newfoundland. 
The  first  specimens  have  been  received  from  the  coral  sea  of  the 
Indian  Archipelago  and  from  the  North  Pacific.  They  were  col- 
lected by  the  surveying  expedition  employed  in  those  seas.  A 
few  soundings  have  been  made  in  the  South  Atlantic,  but  not 
enough  to  justify  deduction  as  to  its  depths  or  the  shape  of  its 
floor. 


THE  BASIN  OF  THE  ATLANTIC  251 


CHAPTER  XIII. 

THE   BASIN   OF   THE   ATLANTIC. 

Its  Shape,  ^  704.— Plate  XL,  709.— The  deepest  Part  of  the  Atlantic,  710.— The  Use 
of  Deep-sea  Soundings,  713. — The  telegraphic  Plateau,  714. — It  extends  around 
the  Earth  as  a  Ridge,  715. — The  first  Specimens  with  Brooke's  Lead,  717. — The 
Bottom  of  the  Sea  a  Burial-place,  724. — The  leveling  Agencies  at  work  there,  730. 
— ^Marine  Insects  presented  in  a  new  Light,  734. — Conservators  of  the  Sea,  739. — 
Calcareous  Shells,  742. — Tallying  marine  Currents,  745. — A  Cast  of  7000  Fathoms 
in  the  Indian  Ocean,  750. — Bottom  from  the  Coral  Sea,  751. — Microscopic  Exam- 
ination of,  753.— The  Bed  of  the  Ocean,  761. 

703.  The  Basin  of  the  Atlantic,  according  to  the  deep-sea 
soundings  made  by  the  American  Navy,  in  the  manner  described 
in  the  foregoing  chapter,  is  shown  on  Plate  XI.  This  plate  refers 
chiefly  to  that  part  of  the  Atlantic  which  is  included  within  our 
hemisphere. 

704.  In  its  entire  length,  the  basin  of  this  sea  is  a  long  trough, 
separating  the  Old  World  from  the  Xew,  and  extending  probably, 
from  pole  to  pole. 

705.  This  ocean-furrow  was  scored  into  the  solid  crust  of  our 
planet  by  the  Almighty  hand,  that  there  the  waters  which  "he 
called  seas"  might  be  gathered  together,  so  as  to  "  let  the  dry  land 
appear,"  and  fit  the  earth  for  the  habitation  of  man. 

706.  From  the  top  of  Chimborazo  to  the  bottom  of  the  Atlan- 
tic, at  the  deepest  place  yet  reached  by  the  plummet  in  the  North 
Atlantic,  the  distance,  in  a  vertical  line,  is  nine  miles. 

707.  Could  the  waters  of  the  Atlantic  be  drawn  oif,  so  as  to  ex- 
pose to  view  this  great  sea-gash,  which  separates  continents,  and 
extends  from  the  Arctic  to  the  Antarctic,  it  would  present  a  scene 
the  most  rugged,  grand,  and  imposing.  The  very  ribs  of  the  solid 
earth,  with  the  foundations  of  the  sea,  would  be  brought  to  light, 
and  we  should  have  presented  to  us  at  one  view,  in  the  empty 
cradle  of  the  ocean,  "  a  thousand  fearful  wrecks,"  with  that  dread- 
ful array  of  dead  men's  skulls,  great  anchors,  heaps  of  pearl  and 


252  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

inestimable  stones,  wliicli,  in  the  dreamer's  eye,  lie  scattered  on 
the  bottom  of  the  sea,  making  it  hideous  with  sights  of  ugly  death. 

708.  To  measure  the  elevation  of  the  mountain-top  above  the 
sea,  and  to  lay  down  upon  our  maps  the  mountain  ranges  of  the 
earth,  is  regarded  in  geography  as  an  important  thing,  and  rightly 
so.  Equally  important  is  it,  in  bringing  the  physical  geography 
of  the  sea  regularly  within  the  domains  of  science,  to  present  its 
orography,  by  mapping  out  the  bottom  of  the  ocean  so  as  to  show 
the  depressions  of  the  solid  parts  of  the  earth's  crust  there  below 
the  sea-level. 

709.  Plate  XI.  presents  the  second  attempt  at  such  a  map.  It 
relates  exclusively  to  the  bottom  of  that  part  of  the  Atlantic  Ocean 
which  lies  north  of  10°  south.  It  is  stippled  with  four  shades  ;  the 
darkest  (that  which  is  nearest  the  shore-line)  shows  where  the  wa- 
ter is  less  than  six  thousand  feet  deep  ;  the  next,  where  it  is  less 
than  twelve  thousand  feet ;  the  third,  where  it  is  less  than  eighteen 
thousand ;  and  the  fourth,  or  lightest,  where  it  is  not  over  twenty- 
four  thousand  feet  deep.  The  blank  space  south  of  Nova  Scotia 
and  the  Grand  Banks  includes  a  district  within  which  very  deep 
water  has  been  reported,  but  from  casts  of  the  deep-sea  lead  which 
upon  discussion  do  not  appear  satisfactory. 

710.  The  deepest  part  of  the  North  Atlantic  (§  702)  is  probably 
somewhere  between  the  Bermudas  and  the  Grand  Banks,  but  how 
deep  it  may  be  yet  remains  for  the  cannon  ball  and  sounding-twine 
to  determine. 

711.  The  waters  of  the  Gulf  of  Mexico  are  held  in  a  basin  about 
a  mile  deep  in  the  deepest  part. 

712.  The  Bottom  of  the  Atlantic,  or  its  depressions  below 
the  sea-level,  are  given,  perhaps,  on  this  plate  with  as  much  accu- 
racy as  the  best  geographers  have  been  enabled  to  show  on  a  map, 
the  elevatix)ns  above  the  sea-level  of  the  interior  either  of  Africa 
or  Australia. 

713.  "  What  is  to  be  the  use  of  these  deep-sea  soundings?"  is 
a  question  that  often  occurs ;  and  it  is  as  difficult  to  be  answered 
in  categorical  terms  as  Franklin's  question,  "  What  is  the  use  of 
a  new-born  babe  ?"  Every  pliysical  fact,  every  expression  of  na- 
ture, every  feature  of  the  earth,  the  work  of  any  and  all  of  those 


THE  BASIN  OF  THE  ATLANTIC.  253 

agents  -wliicli  make  tlie  face  of  tlie  world  what  it  is,  and  as  we 
see  it,  is  interesting  and  instructive.  Until  we  get  hold  of  a  group 
of  physical  facts,  we  do  not  know  what  practical  bearings  they 
may  have,  though  right-minded  men  know  that  they  contain  many 
precious  jewels,  which  science  or  the  expert  hand  of  philosophy 
will  not  fail  to  bring  out,  polished,  and  bright,  and  beautifully 
adapted  to  man's  purposes;  Ah'cady  we  are  obtaining  practical 
answers  to  this  cjuestion  as  to  the  use  of  deep-sea  soundings  ;  for 
as  soon  as  they  were  announced  to  the  public,  they  forthwith  as- 
sumed a  practical  bearing  in  the  minds  of  men  with  regard  to  the 
question  of  a  submarine  telegraph  across  the  Atlantic. 

714.  There  is  at  the  bottom  of  this  sea,  between  Cape  Race  in 
Newfoundland  and  Cape  Clear  in  Ireland,  a  remarkable  stej)pe, 
which  is  already  known  as  the  telegraphic  plateau.  A  company 
is  now  engaged  with  the  project  of  a  submarine  telegraph  across 
the  Atlantic.  It  is  proposed  to  carry  the  wires  along  this  plateau 
from  the  eastern  shores  of  Newfoundland  to  the  western  shores 
of  Ireland.  The  great-circle  distance  between  these  two  shore- 
lines is  one  thousand  six  hundred  and  forty  miles,  and  the  sea 
along  the  route  is  probably  nowhere  more  than  ten  or  twelve 
thousand  feet  deep.  This  company,  it  is  understood,  consists  of 
men  of  enterprise  and  wealth,  who  have  satisfied  themselves  as  to 
the  practicability  of  the  scheme.  They  hare  made  a  contract  with 
a  party  in  England,  who  have  agreed  to  deliver  to  them  by  June, 
1858,  a  telegraphic  cable,  stretched  from  Ireland,  upon  this  plateau, 
to  Newfoundland.  It  was  this  company  that  attempted  last  sum- 
mer to  stretch  a  telegraphic  cable  from  Port  au  Basque,  in  New- 
foundland, to  Cape  Breton,  and  lost  it.  It  is  hoped  that  no  such 
failure  will  happen  to  the  great  line,  for,  w^ith  proper  precaution 
and  management,  success  is  certain. 

715.  There  appears  to  be,  corresponding  to  this  elevation  of  the 
bottom  of  the  sea,  a  ridge  on  the  land  which  runs  nearly,  if  not 
entirely  around  the  earth.  Leaving  this  continent  between  the 
parallels  of  45°  and  50°  north,  the  British  islands  are  within  its 
range.  Passing  thence  to  the  continent,  we  recognize  it  in  the 
great  "  divide"  which  separates  the  drainage  of  the  Arctic  Ocean 
from  the  drainage  south.     In  Asia  it  rises  up  into  a  chain  of 


254       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

steppes  and  mountains,  extending  across  that  continent  from  west 
to  east,  and  disappearing  on  the  shores  of  the  Pacific.  We  do 
not  know  how  it  is  at  the  bottom  of  the  "  Grand  Ocean,"  but  the 
chain  of  Aleutian  islands,  rising  out  of  the  water  midway  between 
Asia  and  America,  seem  to  suggest  that  it  is  there  also.  How- 
ever, if  we  run  the  eye  along  to  America,  we  shall  perceive  again, 
as  soon  as  we  come  to  this  continent,  indications  of  this  ridge, 
which  here  divides  the  waters  that  flow  north  from  those  that  seek 
the  ocean  in  more  southern  latitudes. 

716.  It  was  upon  this  ridge  or  plateau,  as  it  crosses  the  Atlan- 
tic, that  Brooke's  sounding  apparatus  brought  up  its  first  trophies 
from  the  bottom  of  the  sea.  These  specimens  Lieutenant  Berry- 
man  and  his  officers  judged  to  be  clay  ;  but  they  took  the  precau- 
tion to  label  them,  carefully  to  preserve  them,  and,  on  their  re- 
turn to  the  United  States,  to  send  them  to  the  proper  bureau. 
They  were  divided :  a  part  was  sent  for  examination  to  Professor 
Ehrenberg,  of  Berlin,  and  apart  to  Professor  Bailey,  of  West  Point 
— eminent  microscopists  both.  I  have  not  heard  from  the  former, 
but  the  latter,  in  November,  1853,  thus  responded : 

717.  "I  am  greatly  obliged  to  you  for  the  deep  soundings  you 
sent  me  last  week,  and  I  have  looked  at  them  with  great  interest. 
They  are  exactly  what  I  have  wanted  to  get  hold  of.  The  bottom 
of  the  ocean  at  the  depth  of  more  than  tioo  iniles  I  hardly  hoped 
ever  to  have  a  chance  of  examining ;  yet,  thanks,  to  Brooke's  con- 
trivance, we  have  it  clean  and  free  from  grease,  so  that  it  can  at 
once  be  put  under  the  microscope.  I  was  greatly  delighted  to 
find  that  all  these  deep  soundings  are  filled  with  microscopic 
shells ;  not  a  particle  of  sand  or  gravel  exists  in  them.  They  are 
chiefly  made  up  of  perfect  little  calcareous  shells  {Foramiiiiferce), 
and  contain,  also,  a  small  number  of  silicious  shells  {Diatomaceoe), 

"It  is  not  probable  that  these  animals  lived  at  the  depths  where 
these  shells  are  found,  but  I  rather  think  that  they  inhabit  the  wa- 
ters near  the  surface ;  and  when  they  die,  their  shells  settle  to  the 
bottom.  With  reference  to  this  point,  I  shall  be  very  glad  to  ex- 
amine bottles  of  water  from  various  depths  which  were  brought 
home  by  the  Dolphin,  and  any  similar  materials,  either  '  bottom,' 
or  water  from  other  localities.    I  shall  study  them  carefully 


THE  BASIN  OF  THE  ATLANTIC.  255 

The  results  already  obtained  are  of  very  great  interest,  and  have 

many  important  bearings  on  geology  and  zoology 

"  I  hope  you  will  induce  as  many  as  possible  to  collect  sound- 
ings with  Brooke's  lead  in  all  parts  of  the  world,  so  that  we  can 
map  out  the  animalcula?  as  you  have  the  whales.  Get  your  whal- 
ers also  to  collect  mud  from  pancake  ice,  etc.,  in  the  Polar  re- 
gions :  this  is  always  full  of  interesting  microscopic  forms." 

718.  These  little  mites  of  shells  seem  to  form  but  a  slender 
clew  indeed  by  which  the  chambers  of  the  deep  are  to  be  thread- 
ed, and  mysteries  of  the  ocean  revealed ;  yet  the  results  are  sug- 
gestive ;  in  right  hands  and  to  right  minds,  they  are  guides  to  both 
light  and  knowledge. 

719.  The  first  noticeable  thing  the  microscope  gives  of  these 
specimens  is,  that  all  of  them  are  of  the  animal,  not  one  of  the 
mineral  kingdom. 

720.  The  ocean  teems  with  life,  we  know.  Of  the  four  ele- 
ments of  the  old  philosophers — fire,  earth,  air,  and  water — perhaps 
the  sea  most  of  all  abounds  with  living  creatures.  The  space  oc- 
cupied on  the  surface  of  our  planet  by  the  different  families  of  an- 
imals and  their  remains  is  inversely  as  the  size  of  the  individual. 
The  smaller  the  animal,  the  greater  the  space  occupied  by  his  re- 
mains. Though  not  invariably  the  case,  yet  this  rule,  to  a  certain 
extent,  is  true,  and  will,  therefore,  answer  our  present  purposes, 
which  are  simply  those  of  illustration :  Take  the  elephant  and 
his  remains,  or  a  microscopic  animal  and  his,  and  compare  them. 
The  contrast,  as  to  space  occupied,  is  as  striking  as  that  of  the 
coral  reef  or  island  with  the  dimensions  of  the  whale.  The  grave- 
yard that  would  hold  the  corallines  is  larger  than  the  grave-yard 
that  would  hold  the  elephants. 

721.  We  notice  another  practical  bearing  in  this  group  of  phys- 
ical facts  that  Brooke's  apparatus  fished  up  from  the  bottom  of  the 
deep  sea.  Bailey,  with  his  microscope  (§  717),  could  not  detect 
a  single  particle  of  sand  or  gravel  among  these  little  mites  of 
shells.  They  were  from  the  great  telegraphic  plateau  (§  714),  and 
the  inference  is  that  there,  if  any  where,  the  waters  of  the  sea  are 
at  rest.  There  was  not  motion  enough  there  to  abrade  these  very 
delicate  organisms,  nor  current  enough  to  sweep  them  about  and 


256       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

mix  up  with  tliem  a  grain  of  the  finest  sand,  nor  the  smallest  par- 
ticle of  gravel  torn  from  the  loose  beds  of  debris  that  here  and 
there  strew  the  bottom  of  the  sea.  This  plateau  is  not  too  deep 
for  the  wire  to  sink  down  and  rest  upon,  yet  it  is  not  so  shallow 
that  currents,  or  icebergs,  or  any  abrading  force  can  derange  the 
wire  after  it  is  once  lodged  upon  it. 

722.  As  Professor  Bailey  remarks,  the  animalcule?,  whose  re- 
mains Brooke's  lead  has  brought  up  from  the  bottom  of  the  deep 
sea,  probably  did  not  live  or  die  there.  They  would  have  had  no 
light  there,  and,  had  they  lived  there,  their  frail  little  textures  would 
have  been  subjected  in  their  growth  to  a  pressure  upon  them  of  a 
column  of  water  twelve  thousand  feet  high,  equal  to  the  weight 
of  four  hundred  atmospheres.  They  probably  lived  and  sported 
near  the  surface,  where  they  could  feel  the  genial  influence  of  both 
light  and  heat,  and  were  buried  in  the  lichen  caves  below  after 
death. 

723.  Brooke's  lead  and  the  microscope,  therefore,  it  would  seem, 
are  about  to  teach  us  to  regard  the  ocean  in  a  new  light.  Its  bo- 
som, which  so  teems  with  animal  life ;  its  face,  upon  which  time 
writes  no  wrinkles — makes  no  impression — are,  it  would  now  seem, 
as  obedient  to  the  great  law  of  change  as  is  any  department  what- 
ever, either  of  the  animal  or  the  vegetable  kingdom.  It  is  now 
suggested  that  henceforward  we  should  view  the  surface  of  the 
sea  as  a  nursery  teeming  with  nascent  organisms,  its  depths  as  the 
cemetery  for  families  of  living  creatures  that  outnumber  the  sands 
on  the  sea-shore  for  multitude. 

724.  Where  there  is  a  nursery,  hard  by  there  will  be  found  also 
a  grave-yard — such  is  the  condition  of  the  animal  world.  But  it 
never  occurred  to  us  before  to  consider  the  surface  of  the  sea  as 
one  wide  nursery,  its  every  ripple  as  a  cradle,  and  its  bottom  one 
vast  burial-place. 

725.  On  those  parts  of  the  solid  portions  of  the  earth's  crust 
which  are  at  the  bottom  of  the  atmosphere,  various  agents  are  at 
work,  leveling  both  upward  and  downward.  Heat  and  cold,  rain 
and  sunshine,  the  winds  and  the  streams,  all,  assisted  by  the  forces 
of  gravitation,  are  unceasingly  wasting  away  the  high  places  on 
the  land,  and  as  perpetually  filling  up  the  loWo 


THE  BASIN  OF  THE  ATLANTIC.  257 

726.  But  in  contemplating  the  leveling  agencies  that  are  at  work 
upon  the  solid  portions  of  the  crust  of  our  planet,  one  is  led,  at 
first  thought,  almost  to  the  conclusion  that  the  leveling  agents, 
however  active  they  may  be  at  the  bottom  of  the  atmosphere,  are 
comparatively  powerless  at  the  bottom  of  the  sea. 

727.  In  the  deep  sea  there  are  no  abrading  processes  at  work ; 
neither  frosts  nor  rains  are  felt  there,  and  the  force  of  gravitation 
is  so  paralyzed  down  there  that  it  can  not  use  half  its  power,  as 
on  the  dry  land,  in  tearing  the  overhanging  rock  from  the  precipice 
and  casting  it  down  into  the  valley  below. 

728.  When  considering  the  bottom  of  the  ocean,  we  have,  in 
the  imagination,  been  disposed  to  regard  the  waters  of  the  sea  as 
a  great  cushion,  placed  between  the  air  and  the  bed  of  the  ocean 
to  protect  and  defend  it  from  these  abrading  agencies  of  the  atmos- 
phere. 

729.  The  geological  clock  may,  we  thought,  strike  new  periods; 
its  hands  may  point  to  era  after  era ;  but,  so  long  as  the  ocean 
remains  in  its  basin — so  long  as  its  bottom  is  covered  with  blue 
water — so  long  must  the  deep  furrows  and  strong  contrasts  in  the 
solid  crust  below  stand  out  bold,  ragged,  and  grand.  Nothing  can 
fill  up  the  hollows  there ;  no  agent  now  at  work,  that  we  know 
of,  can  descend  into  its  depths,  and  level  off  the  floors  of  the  sea. 

730.  But  it  now  seems  that  we  forgot  these  oceans  of  animal- 
culfe,  that  make  the  surface  of  the  sea  sparkle  and  glow  with  life. 
They  are  secreting  from  its  surface  solid  matter  for  the  very  pur- 
pose of  filling  up  those  cavities  below.  These  little  marine  insects 
are  building  their  habitations  at  the  surface,  and  when  they  die, 
their  remains,  in  vast  multitudes,  sink  down  and  settle  upon  the 
bottom.  They  are  the  atoms  of  which  mountains  are  formed  and 
plains  spread  out.  Our  marl-beds,  the  clay  in  our  river-bottoms, 
large  portions  of  many  of  the  great  basins  of  the  earth,  are  com- 
posed of  the  remains  of  just  such  little  creatures  as  these,  which 
the  ingenuity  of  Brooke  and  the  industry  of  Berryman  have  en- 
abled us  to  fish  up  from  the  depth  of  more  than  two  miles  (twelve 
thousand  feet)  below  the  sea-level. 

731.  TliQ^Q  foraminifeixe,  therefore,  when  living,  may  have  been 
preparing  the  ingredients  for  the  fruitful  soil  of  a  land  that  some 


258       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

earthquake  or  upheaval,  in  ages  far  away  in  the  future,  may  be 
sent  to  cast  up  from  the  bottom  of  the  sea  for  man's  use. 

732.  The  study  of  these  "sunless  treasures,"  recovered  with 
so  much  ingenuity  from  the  rich  bottom  of  the  sea,  suggests  new 
views  concerning  the  physical  economy  of  the  ocean. 

733.  In  the  chapter  on  the  Salts  of  the  Sea,  p.  179, 1  endeav- 
ored to  show  how  sea-shells  and  marine  insects  may,  by  reason  of 
the  offices  which  they  perform,  be  regarded  as  compensations  in 
that  exquisite  system  of  physical  machinery  by  which  the  harmo- 
nies of  nature  are  preserved. 

734.  But  the  treasures  of  the  lead  and  revelations  of  the  micro- 
scope present  the  insects  of  the  sea  in  a  new  and  still  more  striking 
light.  We  behold  them  now  serving  not  only  as  compensations 
by  which  the  motions  of  the  water  in  its  channels  of  circulation 
are  regulated  and  climates  softened,  but  acting  also  as  checks  and 
balances  by  which  the  equipoise  between  the  solid  and  the  fluid 
matter  of  the  earth  is  preserved. 

735.  Should  it  be  established  that  these  microscopic  creatures 
live  at  the  surface,  and  are  only  buried  at  the  bottom  of  the  sea, 
we  may  then  view  them  as  conservators  of  the  ocean  ;  for,  in  the 
offices  which  they  perform,  they  assist  to  preserve  its  status  by 
secreting  the  salts  which  the  rivers  and  the  rains  bring  down  to 
the  sea,  and  thus  maintain  the  purity  of  its  waters. 

736.  The  waters  of  the  Mississippi  and  the  Amazon,  together 
with  all  the  streams  and  rivers  of  the  world,  both  great  and  small, 
hold  in  solution  large  quantities  of  lime,  soda,  iron,  and  other  mat- 
ter. They  discharge  annually  into  the  sea  an  amount  of  this  sol- 
uble matter,  which,  if  precipitated  and  collected  into  one  solid 
mass,  would  no  doubt  surprise  and  astonish  the  boldest  specula- 
tor with  its  magnitude. 

737.  This  soluble  matter  can  not  be  evaporated.  Once  in  the 
ocean,  there  it  must  remain;  and  as  the  rivers  are  continually 
pouring  in  fresh  supplies  of  it,  the  sea,  it  has  been  argued  (§  502), 
must  continue  to  become  more  and  more  salt. 

738.  Now  the  rivers  convey  to  the  sea  this  solid  matter  mixed 
with  fresh  water,  w^iich,  being  lighter  than  that  of  the  ocean,  re- 
mains for  a  considerable  time  at  or  near  the  surface.     Here  the 


THE  BASIN  OF  THE  ATLANTIC.  259 

microscopic  organisms  of  the  deep-sea  lead  are  continually  at  work, 
secreting  this  same  lime  and  soda,  etc.,  and  extracting  from  the  sea- 
water  all  this  solid  matter  as  fast  as  the  rivers  bring  it  down  and 
empty  it  into  the  sea.  They  live  and  die  at  the  surface,  then 
sinking,  the  bottom  of  the  sea  is  strewed  with  them. 

739.  Thus  we  haul  up  from  the  deep  sea  specimens  of  dead  an- 
imals, and  recognize  in  them  the  remains  of  creatures  which,  though 
invisible  to  the  naked  eye,  have  nevertheless  assigned  to  them  a 
most  important  office  in  the  physical  economy  of  the  universe,  viz., 
that  of  regulating  the  saltness  of  the  sea  (§  563). 

740.  This  view  suggests  many  contemplations.  Among  them, 
one  in  which  the  ocean  is  presented  as  a  vast  chemical  bath,  where 
the  solid  parts  of  the  earth  are  washed,  filtered,  and  precipitated 
again  as  solid  matter,  but  in  a  new  form,  and  with  fresh  properties. 

Doubtless  it  is  only  a  re-adaptation — though  it  may  be  in  an  im- 
proved form — of  old,  and  perhaps  effete  matter,  to  the  uses  and 
well-being  of  man. 

741.  These  are  speculations  merely ;  they  may  be  fancies  with- 
out foundation,  but  idle  they  are  not,  I  am  sure  ;  for  when  we  come 
to  consider  the  agents  by  which  the  physical  economy  of  this  our 
earth  is  regulated,  by  which  this  or  that  result  is  brought  about  and 
accomplished  in  this  beautiful  system  of  terrestrial  arrangements, 
we  are  utterly  amazed  at  the  offices  which  have  been  ]Derformed, 
the  work  which  has  been  done,  by  the  animalculas  of  the  water. 

742.  But  whence  come  the  little  calcareous  shells  which 
Brooke's  lead  has  brought  up,  in  proof  of  its  sounding,  from  the 
depth  of  two  miles  and  a  quarter  ?  Did  they  live  in  the  surface 
waters  immediately  above  ?  or  is  their  habitat  in  some  remote  part 
of  the  sea,  whence,  at  their  death,  the  currents  were  sent  forth  as 
pall-bearers,  with  the  command  to  deposit  their  remains  where  the 
plummet  found  them  ? 

743.  In  this  view,  these  little  organisms  become  doubly  inter- 
esting. When  dead,  the  descent  of  the  shell  to  its  final  resting- 
place  would  not,  it  may  be  supposed,  be  very  rapid.  It  would 
partake  of  the  motion  of  the  sea-water  in  which  it  lived  and  died, 
and  probably  be  carried  along  with  it  in  its  channels  of  circulation 
for  many  a  long  mile. 

R 


260       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

744.  The  microscope,  under  the  eye  of  Ehrenberg,  has  enabled 
us  (§  272)  to  put  tallies  on  the  wings  of  the  wind,  to  learn  of  them 
somewhat  concerning  its  "circuits." 

745.  Now  may  not  these  shells,  which  were  so  fine  and  impal- 
pable that  the  officers  of  the  Dolphin  took  them  to  be  a  mass  of  unc- 
tuous clay — may  not,  I  say,  these,  with  other  specimens  of  sound- 
ings yet  to  be  collected,  be  all  converted  by  the  microscope  into 
tallies  for  the  waters  of  the  different  parts  of  the  sea,  by  which  the 
channels  through  which  the  circulation  of  the  ocean  is  carried  on 
are  to  be  revealed  ? 

746.  Suppose,  for  instance,  that  the  dwelling-place  of  the  little 
shells  which  compose  this  specimen  from  that  part  of  the  ocean  be 
ascertained,  by  referring  to  living  types,  to  be  the  Gulf  of  Mexico 
or  some  other  remote  region  ;  that  the  habitat  and  the  burial-place, 
in  evexy  instance,  be  far  removed  from  each  other — by  wliat  agen- 
cy, except  through  that  of  currents,  can  we  suppose  these  little 
creatures — themselves  not  having  the  powers  for  more  than  a  very 
restricted  locomotion — to  come  from  the  place  of  their  birth,  or 
to  travel  to  that  of  their  burial  ? 

747.  Man  can  never  see — he  can  only  touch  the  bottom  of  the 
deep  sea,  and  then  only  with  the  plummet.  Whatever  it  brings 
up  thence  is  to  the  philosopher  matter  of  powerful  interest ;  for  by 
such  information  alone  as  he  may  gather  from  a  most  careful  ex- 
amination of  such  matter,  the  amount  of  human  knowledge  con- 
cerning nearly  all  that  portion  of  our  planet  which  is  covered  by 
the  sea  must  depend. 

748.  Every  specimen  of  bottom  from  the  deep  sea  is,  therefore, 
to  be  regarded  as  probably  containing  something  precious  in  the 
way  of  contribution  to  the  sources  of  human  knowledge  ;  and  each 
as  it  is  brought  up  will  be  viewed  with  increasing  interest,  and  will 
suggest  to  us  thoughts  more  and  more  profitable  concerning  the 
wonders  of  the  deep. 

749.  "  There  has  been  sent,"  says  Brooke,  in  a  letter  from  the 
Surveying  Expedition  of  the  North  Pacific,  "a  table  of  tempera- 
tures at  various  depths,  from  one  hundred  to  five  hundred  fathoms, 
and  two  reports  of  experiments  in  deep-sea  soundings.  Several 
unsuccessful  attempts  to  sound  from  the  ship  were  made  under  the 


THE  BASIN  OF  THE  ATLANTIC.  261 

direction  of  Captain  Einggold,  but  were  considered  Tinwortliy  of  a 
remark — in  wliicli  opinion  I  coincide  ;  for,  at  considerable  depths, 
one  is  entirely  dependent  upon  the  times  of  the  hundred  fathoms. 
As  a  general  thing,  I  suppose  a  hundred  thousand  fathoms  would 
all  be  eventually  taken  from  the  reel  by  the  drift  of  the  ship.  On 
one  of  these  occasions,  a  breeze  sprang  up  on  the  quarter,  shooting 
the  ship  ahead  in  such  a  manner  as  to  render  the  cast  utterly 
worthless. 

750.  "  From  our  experience  in  the  Indian  Ocean  and  Coral  Sea, 
I  am  inclined  to  believe  that  there  is  no  depth  from  which  speci- 
mens of  the  bottom  may  not  be  obtained.  It  will  ever  be  a 
source  of  regret  that,  owing  to  circumstances  beyond  my  control, 
we  were  unsuccessful  in  recovering  the  line  and  specimen  after 
reaching  bottom  with  7040  fathoms,  in  the  Indian  Ocean.  Such 
opportunities  are  rare  in  that  locality ;  yet,  owing  to  the  current 
of  sixty  miles,  it  will  be  a  difficult  matter  to  determine  the  abso- 
lute depth.  That  current  was  not  as  superficial  as  one  might  at 
first  suppose,  for  it  was  during  the  latter  part  of  the  operation  that 
the  boat  experienced  its  effect,  and  it  would  seem  that,  had  the 
current  been  superficial,  the  line  would  have  given  indication  by 
tending  ahead,  whereas  it  ran  right  down.  Moreover,  that  current 
was  local,  which  adds  to  the  probability  of  its  depth. 

751.  "  The  cast  made  in  the  Qoral  Sea  was  satisfactory  in  ev- 
ery respect.  The  arming-rod  came  up  with  its  lower  extremity 
completely  coated  with  what  appeared  to  be  a  calcareous  clay  of 
such  adhesive  and  tenacious  character  as  to  preserve  the  marks  of 
the  shot  made  in  slipping  off.  In  fact,  we  had  fallen  upon  one  of 
those  beds  which  evidently  present  the  characteristic  formations 
of  England." 

752.  This  specimen  from  the  Coral  Sea,  lat.  13°  south,  long. 
162°  east,  was  brought  up  by  Brooke's  sounding-rod  from  the 
reported  depth  of  2150  fathoms. 

753.  Professor  Bailey,  to  whom  the  specimen  was  sent  for 
microscopic  examination,  replied:  "You  may  be  sure  I  was 
not  backward  in  taking  a  look  at  the  specimens  you  sent  me, 
which,  from  their  locality,  promised  to  be  so  interesting.  The 
sounding  from  2150  fathoms,  although  small  in  quantity,  is  not 


262  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

bad  in  quality,  yielding  representatives  of  most  of  the  great 
groups  of  microscopic  organisms  usually  found  in  marine  sedi- 
ments. 

"  The  predominant  forms  are  silicious  spicules  of  sponges.  Va- 
rious forms  of  these  occur ;  some  long  and  spindle-shaped  or  acic- 
ular,  others  pin-headed,  some  three-spined,  etc.,  etc. 

"  The  Diatoms  (silicious  infusoria  of  Ehrenberg)  are  very  few 
in  number,  and  mostly  fragmentary.  I  found,  however,  some  per- 
fect valves  of  a  Coscinodiscus. 

"  The  Foraminifera  (Polythalamia  of  Ehrenburg)  are  very  rare, 
only  one  perfect  shell  being  seen,  with  a  few  fragments  of  others. 

"  The  Polycistinise  are  present,  and  some  species  of  Haliomma 
were  quite  perfect.  Fragments  of  other  forms  of  this  group  indi- 
cate that  various  interesting  species  might  be  obtained  if  we  had 
more  of  the  material. 

754.  "You  see  by  the  above  that  this  deep-sounding  differs 
considerably  from  those  obtained  in  the  Atlantic.  The  Atlantic 
soundings  were  almost  wholly  composed  of  calcareous  shells  of 
the  Foraminifera ;  these,  on  the  contrary,  contain  very  few  Fora- 
minifera, and  are  of  a  silicious  rather  than  of  a  calcareous  nature. 
This  only  makes  the  condition  of  things  in  the  northern  Atlantic 
the  more  interesting,  because,"  says  this  philosopher,  "  they  prove 
that  deep  water  is  not  necessarily  underlaid  by  foraminiferous  de- 
posits, and  that  some  peculiar  local  conditions  of  temperature,  cur- 
rents, or  geological  substratum,  have  made  the  North  Atlantic  a 
perfect  vivarium  for  the  calcareous  forms. 

755.  "The  chart  (Plate  IX.)  you  send  is  very  interesting,  and 
combines  a  wonderful  amount  of  interesting  phenomena.  I  have 
little  doubt  that  the  history  of  the  bottom  of  the  ocean,  as  record- 
ed by  the  sediments,  would  show  a  close  relation  to  the  facts  de- 
termined for  the  surface,  besides  many  unexpected  relations.  I 
am  very  anxious  to  get  some  soundings  from  the  great  ocean  cur- 
rent that,  as  shown  in  your  chart,  sweeps  in  through  the  Carib- 
bean Sea  and  along  the  coast  of  Mexico  and  Texas. 

756.  "  I  observe  on  your  chart  something  which  looks  like  a 
sargasso  sea  southeast  of  Madagascar.  Is  it  so  ?  Get  sound- 
ings, if  possible,  in  these  sargasso  seas.     Get  soundings  any  where 


THE  BASIN  OF  THE  ATLANTIC.  263 

— every  where.     Even  wlien  they  yield  nothing,  the  negative  fact 
is  of  value." 

757.  Here,  again,  we  perceive  these  little  conservators  of  the 
sea  at  work.  This  specimen  that  Brooke  has  obtained  for  us 
comes  from  the  coral  regions,  and  the  task  of  secreting  the  calca- 
reous matter  from  the  sea-water  appears  to  have  been  left  by  these 
little  mites  of  creatures*  to  the  madrepore  and  shell-fish,  while 
these  mites  themselves  undertook  the  hard  task  of  getting  the  si- 
licious  matter  out.  The  division  of  labor  among  the  organisms 
of  the  sea  is  wonderful.  It  is  a  great  work-shop,  in  which  the 
machinery  is  so  perfect  that  nothing  ever  goes  wrong. 

758.  Specimens  of  the  "  ooze  and  bottom  of  the  sea"  have  also 
been  obtained  by  the  ingenuity  of  Brooke  from  the  depth  of  2700 
fathoms  in  the  North  Pacific,  and  examined  by  Prof.  Bailey,  f 

*  Maury's  Sailing  Directions^  7th  edition,  p,  155. 

t  "  West  Point,  N.  Y.,  January  29,  1856. 

"  My  dear  Sir, — I  have  examined  with  much  pleasure  the  highly  interesting  speci- 
mens collected  by  Lieutenant  Brooke,  of  the  United  States  Navy,  which  you  kindly 
sent  me  for  microscopic  analysis,  and  I  will  now  briefly  report  to  you  the  results  of 
general  interest  which  I  have  obtained,  leaving  the  enumeration  of  the  organic  con- 
tents and  the  description  of  new  species  for  a  more  complete  account,  which  I  hope 
soon  to  publish.     The  specimens  examined  by  me  were  as  follows,  viz. : 

'*  No.  1.  Sea  bottom,  2700  fathoms  ;  lat.  56°  46'  N.,  long.  168°  18'  E. ;  brought  up 
July  19,  1855,  by  Lieutenant  Brooke,  with  Brooke's  lead.  ' 

"  No.  2.  Sea  bottom,  1700  fathoms  ;  lat.  60°  15'  N.,  long.  170°  53'  E.  ;  brought  up 
as  above,  July  26,  1855. 

"  No.  3.  Sea  bottom,  900  fathoms ;  temperature  (deep  sea)  32°,  Saxton ;  lat.  60° 
30'  N,  long.  175°  E. 

"  A  careful  study  of  the  above  specimens  gave  the  following  results  : 

*'  1st.  All  the  specimens  contain  some  mineral  matter,  which  diminishes  in  propor- 
tion to  the  depth,  and  which  consists  of  minute  angular  particles  of  quartz,  hornblende, 
feldspar,  and  mica. 

"  2d.  In  the  deepest  soundings  (No.  1  and  No.  2)  there  is  the  least  mineral  matter, 
the  organic  contents,  which  are  the  same^  in  all,  predominating,  while  the  reverse  is 
true  of  No.  3. 

"  3d.  All  these  specimens  are  very  rich  in  the  silicious  shells  of  the  Diatomacese, 
which  are  in  an  admirable  state  of  preservation,  frequently  with  the  valves  united, 
and  even  retaining  the  remains  of  the  soft  parts. 

"  4th.  Among  the  Diatoms  the  most  conspicuous  forms  are  the  large  and  beautiful 
disks  of  several  species  of  Coscinodiscus.  There  is  also,  besides  many  others,  a  large 
number  of  a  new  species  of  Rhizosolenia,  a  new  Syndendrium,  a  curious  species  of 
Chsetoceros,  with  furcate  horns,  and  a  beautiful  species  of  Asteromphalus,  which  I 
propose  to  call  Asteromphalus  Brookei,  in  honor  of  Lieutenant  Brooke,  to  whose  in- 


264  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

759.  We  have  now  had  specnnens  from  the  bottom  of  "blue 
water"  in  the  narrow  Coral  Sea,  the  broad  Pacific,  and  the  long- 
Atlantic,  and  they  all  tell  the  same  story,  namely,  that  the  bed  of 
the  ocean  is  a  vast  cemetery.  The  ocean's  bed  has  been  found 
every  where,  wherever  Brooke's  souilding-rod  has  touched,  to  be 

genious  device  for  obtaining  deep  soundings,  and  to  whose  industry  and  zeal  in  using 
it,  we  are  indebted  for  these  and  many  other  treasures  of  the  deep. 

"5th.  The  specimens  contain  a  considerable  number  of  sihcious  spicules  of  sponges, 
and  of  the  beautiful  silicious  shells  of  the  Polycistinese.  Among  the  latter  I  have  no- 
ticed Cornutella  Clathrata  of  Ehrenberg,  a  form  occurring  frequently  in  the  Atlantic 
soundings.  I  have  also  noticed  in  all  these  soundings,  and  shall  hereafter  describe 
and  figure,  several  species  of  Eucyrtidium,  Halicalyptra,  a  Perichlamidium,  a  Stylo- 
dictya,  and  many  others. 

"  6th.  I  have  not  been  able  to  detect  even  a  fragment  of  any  of  the  calcareous  shells 
of  the  Polythalamia.  This  is  remarkable,  from  the  striking  contrast  it  presents  to  the 
deep  soundings  of  the  Atlantic,  which  are  chiefly  made  up  of  these  calcareous  forms. 
This  difference  can  not  be  due  to  temperature,  as  it  is  well  known  that  Polythalamia 
are  abundant  in  the  Arctic  Seas. 

*'  7th.  These  deposits  of  microscopic  organisms,  in  their  richness,  extent,  and  the 
high  latitudes  at  which  they  occur,  resemble  those  of  the  Antarctic  regions,  whose  ex- 
istence has  been  proved  by  Ehrenberg,  and  the  occurrence  in  these  northern  sound- 
ings of  species  of  Asteromphalus  and  Chsetoceros  is  another  striking  point  of  resem- 
blance. These  genera,  however,  are  not  exclusively  polar  forms,  but,  as  I  have  re- 
cently determined,  occur  also  in  the  Gulf  of  Mexico  and  along  the  Gulf  Stream. 

"  8th.  The  perfect  condition  of  the  organisms  in  these  soundings,  and  the  fact  that 
some  of  them  retain  their  soft  portions,  indicate  that  they  were  very  recently  in  a  liv- 
ing condition,  but  it  does  not  follow  that  they  were  living  when  collected  at  such  im- 
mense depths.  As  among  them  are  forms  which  are  known  to  live  along  the  shores 
as  parasites  upon  the  Algse,  &c.,  it  is  certain  that  a  portion,  at  least,  have  been  car- 
ried by  oceanic  currents,  by  drift  ice,  by  animals  which  have  fed  upon  them,  or  by 
other  agents,  to  their  present  position.  It  is  hence  probable  that  all  were  removed 
from  shallower  waters  in  which  they  once  lived.  These  forms  are  so  minute,  and 
would  float  so  far  when  buoyed  up  by  the  gases  evolved  during  decomposition,  that 
there  would  be  nothing  surprising  in  finding  them  in  any  part  of  the  ocean,  even  if 
they  were  not  transported,  as  it  is  certain  they  often  are,  by  the  agents  above  refer- 
red to. 

"  9th.  In  conclusion,  it  is  to  be  hoped  that  the  example  set  by  Lieutenant  Brooke 
will  be  followed  by  others,  and  that,  in  all  attempts  to  make  deep  soundings,  the  effort 
to  bring  up  a  portion  of  the  bottom  will  be  made.  The  soundings  from  any  part  of 
the  ocean  are  sure  to  yield  something  of  interest  to  microscopic  analysis,  and  it  is  as 
yet  impossible  to  tell  what  important  results  may  yet  flow  from  their  study. 

"  The  above  is  only  a  preliminary  notice  of  the  soundings  referred  to.  I  shall  pro- 
ceed without  delay  to  describe  and  figure  the  highly  interesting  and  novel  forms  which 
I  have  detected,  and  I  hope  soon  to  have  them  ready  for  publication. 

"  Yours,  very  respectfully,  J.  W.  Bailey. 

"Lieutenant  M.  F.  Maurv,  National  Observatory,  Washington  City,  D.  C" 


THE  BASIN  OF  THE  ATLANTIC.  265 

soft,  consisting  almost  entirely  of  the  remains  of  infusoria.  The 
Gulf  Stream  has  literally  strewed  the  bottom  of  the  Atlantic  with 
these  microscopic  shells ;  for  the  Coast  Survey  has  caught  up  the 
same  infusoria  in  the  Gulf  of  Mexico  and  at  the  bottom  of  the 
Gulf  Stream  off  the  shores  of  the  Carolinas,  that  Brooke's  appara- 
tus brought  up  from  the  bottom  of  the  Atlantic  oif  the  Irish  coast. 

760.  The  unabraded  appearance  of  these  shells,  and  the  almost 
total  absence  of  the  mixture  of  any  detritus  from  the  sea  or  foreign 
matter,  suggest  most  forcibly  the  idea  of  perfect  repose  at  the  bot- 
tom of  the  deep  sea. 

761.  Some  of  the  specimens  that  Brooke's  apparatus  has 
brought  up  are  as  pure  and  as  free  from  the  sand  of  the  sea  as 
the  snow-flake  that  falls,  when  it  is  calm,  upon  the  lea,  is  from  the 
dust  of  the  earth.  Indeed,  these  soundings  suggest  the  idea  that 
the  sea,  like  the  snow-cloud  with  its  flakes  in  a  calm,  is  always 
letting  fall  upon  its  bed  showers  of  these  microscopic  shells ;  and 
we  may  readily  imagine  that  the  "sunless  wrecks,"  which  strew 
its  bottom,  are,  in  the  process  of  ages,  hid  under  this  fleecy  cov- 
ering, presenting  the  rounded  appearance  which  is  seen  over  the 
body  of  the  traveler  who  has  perished  in  the  snow-storm.  The 
ocean,  especially  within  and  near  the  tropics,  swarms  with  life. 
The  remains  of  its  myriads  of  moving  things  are  conveyed  by 
currents,  and  scattered  and  lodged  in  the  course  of  time  all  over 
its  bottom.  This  process,  continued  for  ages,  has  covered  the 
depths  of  the  ocean  as  with  a  mantle,  consisting  of  organisms  as 
delicate  as  the  macled  frost,  and  as  light  as  the  undrifted  snow- 
flake  on  the  mountain.* 

*  See  Addenda. 


266  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  XIV. 

THE  WINDS. 

Belt  of  Southeast  broader  than  Northeast,  ^  764. — Tracks  of  Vessels  across  the  South- 
east Trades,  767. — Scenes  in  the  Trade-wind  Regions,  770. — The  Effect  of  South 
Africa  and  America  upon  the  Winds,  779. — Monsoons,  787. — Dove's  Theory,  789. 
— Proof  that  the  Southwest  Monsoons  are  the  Southeast  Trades  deflected,  797. — 
How  the  Southwest  Monsoons  march  toward  the  Equator,  806. — How  the  Monsoon 
Season  may  be  known,  809. — Influence  of  Deserts  upon  the  Winds,  810. — Chang- 
ing of  the  Monsoons,  819. — West  Monsoon  in  Java  Sea,  823. — Water-spouts,  826. 
— Influence  of  Currents  upon  Winds,  829. — Tlie  Calm  Belts,  835. — The  Equatorial 
Calms,  837.— The  Horse  Latitudes,  840.— The  Westerly  Winds,  843.— The  brave 
West  Winds  of  the  Southern  Hemisphere,  846. 

762.  Plate  VIII.  is  a  chart  of  the  winds,  based  on  information 
derived  from  the  Pilot  Charts,  one  of  the  series  of  Maurj's  Wind 
and  Current  Charts.  The  object  of  this  chart  is  to  make  the  stu- 
dent acquainted  with  the  prevailing  direction  of  the  wind  in  every 
part  of  the  ocean. 

The  arrows  of  the  plate  are  supposed  to  fly  with  the  wind ;  the 
half  bearded  and  half  feathered  arrows  denoting  monsoons  or  pe- 
riodic winds ;  the  dotted  bands,  the  regions  of  calm  and  bafihng 
winds. 

763.  Monsoons,  properly  speaking,  are  winds  which  blow  one 
half  of  the  year  from  one  direction,  and  the  other  half  from  an  op- 
posite, or  nearly  an  opposite  direction. 

Let  us  commence  the  study  of  Plate  VIII.  by  examining  the 
trade-wind  region  ;  that,  also,  is  the  region  in  which  monsoons  are 
most  apt  to  be  found. 

764.  The  belt  or  zone  of  the  southeast  trade-winds  is  broader, 
it  will  be  observed,  than  the  belt  or  zone  of  northeast  trades. 
This  phenomenon  is  explained  by  the  fact  that  there  is  more  land 
in  the  northern  hemisphere,  and  that  most  of  the  deserts  of  the 
earth — as  the  great  deserts  of  Asia  and  Africa — are  situated  in  the 
rear,  or  behind  the  northeast  trades ;  so  that,  as  these  deserts  be- 


THE  WINDS. 


267 


come  more  or  less  heated,  there  is  a  call — a  pulling  back,  if  you 
please — upon  these  trades  to  turn  about  and  restore  the  equilibri- 
um which  the  deserts  destroy.  There  being  few  or  no  such  re- 
gions in  the  rear  of  the  southeast  trades,  the  southeast  trade- wind 
force  prevails,  and  carries  them  over  into  the  northern  hemisphere. 
765.  By  resolving  the  forces  which  it  is  supposed  are  the  prin- 
cipal forces  that  put  these  winds  in  motion,  namely,  calorific  action 
of  the  sun  and  diurnal  rotation  of  the  earth,  we  are  led  to  the  con- 
clusion that  the  latter  is  much  the  greater  of  the  two  in  its  effects 
upon  those  of  the  northern  hemisphere.  But  not  to  such  an  ex- 
tent is  it  gTcater  in  its  effects  upon  those  of  the  southern.  Yie  see 
by  the  plate  that  those  two  opposing  cun-ents  of  wind  are  so  une- 
qually balanced  that  the  one  recedes  before  the  other,  and  that  the 
current  from  the  southern  hemisphere  is  larger  in  volume ;  ^.  e.,  it 
moves  a  greater  zone  or  belt  of  air.  The  southeast  trade-winds 
discharge  themselves  over  the  equator — i.  e.,  across  a  great  circle 
— into  the  region  of  equatorial  calms,  while  the  northeast  trade- 
winds  discharge  themselves  into  the  same  region  over  a  parallel 
of  latitude,  and  consequently  over  a  small  circle.  If,  therefore, 
we  take  what  obtains  in  the  Atlantic  as  the  type  of  what  obtains 
entirely  around  the  earth,  as  it  regards  the  trade- winds,  we  shall 
see  that  the  southeast  trade-winds  keep  in  motion  more  air  than 
the  northeast  do,  by  a  quantity  at  least  proportioned  to  the  dif- 
ference between  the  circumference  of  the  earth  at  the  equator  and 
at  the  parallel  of  latitude  of  9°  north.  For  if  we  suppose  that 
those  two  perpetual  currents  of  air  extend  the  same  distance  from 
the  surface  of  the  earth,  and  move  with  the  same  velocity,  a  great- 
er volume  from  the  south  would  flow  across  the  equator  in  a  given 
time  than  would  flow  from  the  north  over  the  parallel  of  9°  in  the 
same  time ;  the  ratio  between-the  two  quantities  would  be  as  ra- 
dius to  the  secant  of  9°.  Besides  this,  the  quantity  of  land  lying 
within  and  to  the  north  of  the  region  of  the  northeast  trade-winds 
is  much  greater  than  the  quantity  within  and  to  the  south  of  the 
region  of  the  southeast  trade-winds.  In  consequence  of  this,  the 
mean  level  of  the  earth's  surface  within  the  region  of  the  northeast 
trade-winds  is,  it  may  reasonably  be  supposed,  somewhat  above 
the  mean  level  of  that  part  which  is  within  the  region  of  the  south- 


268       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

east  trade-winds.  And  as  the  northeast  trade-winds  blow  under 
the  influence  of  a  greater  extent  of  land  surface  than  the  south- 
east trades  do,  the  former  are  more  obstructed  in  their  course  than 
the  latter  by  the  forests,  the  mountain  ranges,  unequally  heated 
surfaces,  and  other  such  like  inequalities. 

766.  As  already  stated,  the  investigations  show  that  the  mo- 
mentum of  the  southeast  trade-winds  is  sufficient  to  push  the  equa- 
torial limits  of  their  northern  congeners  back  into  the  northern 
hemisphere,  and  to  keep  them,  at  a  mean,  as  far  north  as  the  ninth 
parallel  of  north  latitude.  Besides  this  fact,  they  also  indicate 
that  while  the  northeast  trade-winds,  so  called,  make  an  angle  in 
their  general  course  of  about  23°  with  the  equator  (east-north- 
east), those  of  the  southeast  make  an  angle  of  30°  or  more  with 
the  equator  (southeast  by  east) — I  speak  of  those  in  the  Atlantic — 
thus  indicating  that  the  latter  approach  the  equator  more  directly 
in  their  course  than  do  the  others,  and  that,  consequently,  the  ef- 
fect of  the  diurnal  rotation  of  the  earth  being  the  same  for  like 
parallels,  north  and  south,  the  calorific  influence  of  the  sun  exerts 
more  power  in  giving  motion  to  the  southern  than  to  the  northern 
system  of  Atlantic  trade-winds :  in  other  words,  the  southeast 
trade-winds  are,  on  the  average,  fresher  than  the  northeast. 

767.  The  southeast  trade-winds  of  the  Atlantic,  particularly  in 
our  summer  and  fall  months,  haul  more  and  more  toward  the  south 
as  they  approach  the  equator.  The  tracks  of  vessels  bound  to 
India  from  Europe  show  this  in  a  very  striking  manner.  They 
cross  the  equator  generally  about  the  meridian  of  20°  west ;  there 
they  find  the  wind  from  southeast,  frequently  from  south-south- 
east, which  forces  the  vessel  offupon  a  course  west  of  south.  As 
the  vessel  gets  south,  the  winds  haul  more  and  more  to  the  east, 
so  that,  before  clearing  the  belt  of  the  southeast  trades,  the  India- 
bound  trader  is  steering  to  the  east  of  south. 

768.  That  the  land  of  the  northern  hemisphere  does  assist  to 
turn  these  winds  is  rendered  still  more  probable  from  this  circum- 
stance :  All  the  great  deserts  are  in  the  northern  hemisphere,  and 
the  land-surface  is  also  much  greater  on  our  side  of  the  equator. 
The  action  of  the  sun  upon  these  unequally  absorbing  and  radiat- 
ing surfaces  in  and  behind,  or  to  the  northward,  of  the  northeast 


THE  WINDS. 


269 


trades,  tends  to  check  these  winds,  and  to  draw  in  large  volumes 
of  the  atmosphere,  that  otherwise  would  be  moved  hy  them, 
to  supply  the  partial  vacuum  made  by  the  heat  of  the  sun,  as  it 
pours  down  its  rays  upon  the  vast  plains  of  burning  sands  and 
unequally  heated  land-surfaces  in  our  overheated  hemisphere. 
The  northwest  winds  of  the  southern  arc  also,  it  may  be  inferred, 
stronger  than  the  southwest  winds  of  the  northern  hemisphere. 

769.  "  A  ship  leaving  the  English  Channel  to  go  to  the  equator 
generally  aims,"  says  Jansen,  "to  come  too  soon  into  the  north- 
east trade.  The  winds  which  prevail  most,  northward  of  the  calm 
belt  of  Cancer,  are  the  southwest.  Wind  and  weather  in  this  part 
of  the  Atlantic  Ocean  are  very  unreliable  and  changeable  ;  never- 
theless, in  the  summer  months,  we  find  permanent  north  winds 
along  the  coast  of  Portugal.  These  north  winds  are  worthy  of  at- 
tention, the  more  so  from  the  fact  that  they  occur  simultaneously 
with  the  African  monsoon,  and  because  we  then  find  northerly 
winds  also  in  the  llediterranean,  and  in  the  Eed  Sea,  and  farther 
eastward  to  the  north  of  the  Indian  monsoon. 

770.  "When,  between  the  months  of  May  and  November,  during 
which  the  African  monsoon  prevails,  the  Dutch  ships,  which  have 
lingered  in  the  calm  belt  of  Cancer,  run  with  the  northeast  trade 
and  direct  their  course  for  tlie  Cape  Yerd  Islands,  then  it  seems  as 
if  they  were  in  another  world.  The  sombre  skies  and  changeable — 
alternately  chilly  and  sultry — weather  of  our  latitudes  are  replaced 
by  a  regular  temperature  and  good  settled  weather.  Each  one  re- 
joices in  the  glorious  heavens,  in  which  none  save  the  little  trade- 
clouds  are  to  be  seen — which  clouds  in  the  trade- wind  region  make 
the  sunset  so  enchanting.  The  dark  blue  water,  in  which  many 
and  strange  kinds  of  echinas  sport  in  the  sunlight,  and,  when  seen 
at  a  distance,  make  the  sea  appear  like  one  vast  field  adorned  with 
flowers ;  the  regular  swellings  of  the  waves  with  their  silvery  foam, 
through  which  the  flying-fishes  flutter;  the  beautifully  colored  dol- 
phins ;  the  diving  schools  of  tunnies  —  all  these  banish  afar  the 
monotony  of  the  sea,*  awake  the  love  of  life  in  the  youthful  sea- 

*  When  we,  as  our  forefathers  did,  preserve  in  the  journals  all  that  we  observe  at 
sea,  then  we  shall  have  abundant  material  with  which  to  keep  ourselves  pleasantly 
occupied. 


270  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

man,  and  attune  his  heart  to  goodness.     Every  thmg  around  him 
fixes  his  attention  and  increases  his  astonishment. 

771.  "If  all  the  outbreathings  of  heartfelt  emotion  which  the 
contemplation  of  nature  forces  from  the  sailor  were  recorded  in  the 
log-books,  how  much  farther  should  we  be  advanced  in  the  knowl- 
edge of  the  natural  state  of  the  sea !  Once  wandering  over  the 
ocean,  he  begins  to  be  impressed  by  the  grand  natural  tableau 
around  him  with  feelings  deep  and  abiding.  The  most  splendid 
forecastle  is  lost  in  the  viewless  surface,  and  brings  home  to  us 
the  knowledge  of  our  nothingness  ;  the  greatest  ship  is  a  plaything 
for  the  billows,  and  the  slender  keel  seems  to  threaten  our  exist- 
ence every  moment.  But  when  the  eye  of  the  mind  is  permitted 
to  wander  through  space  and  into  the  depths  of  the  ocean,  and  is 
able  to  form  a  conception  of  Infinity  and  of  Omnipotence,  then  it 
knows  no  danger ;  it  is  elevated — it  comprehends  itself.  The  dis- 
tances of  the  heavenly  bodies  are  correctly  estimated;  and,  en- 
lightened by  astronomy,  with  the  aid  of  the  art  of  navigation,  of 
which  ]\Iaury's  Wind  and  Current  Charts  form  an  important  part, 
the  shipmaster  marks  out  his  way  over  the  ocean  just  as  securely 
as  any  one  can  over  an  extended  heath.  He  directs  his  course 
toward  the  Cape  Verd  Islands,  and  is  carried  there  by  the  lively 
trade-wind.  Yet  beyond  the  islands,  sooner  or  later,  according  to 
what  month  it  is,  the  clear  skies  begin  to  be  clouded,  the  trade- 
wind  abates  and  becomes  unsteady,  the  clouds  heap  up,  the  thun- 
der is  heard,  heavy  rains  fall ;  finally,  the  stillness  is  death-like, 
and  we  have  entered  the  belt  of  calms.  This  belt  moves  toward 
the  north  from  May  to  September.  It  is  a  remarkable  phenome- 
non that  the  annual  movements  of  the  trades  and  calm  belts  from 
south  to  north,  and  back  again,  do  not  directly  follow  the  sun  in 
its  declination,  but  appear  to  wait  until  the  temperature  of  the  sea- 
water  puts  it  in  motion.  The  trades  and  the  belt  of  calms  do  not 
decline  before  the  temperature  of  80°  of  the  water  in  the  north 
Atlantic  Ocean  turns  it  southward,  and  in  the  spring  they  do  not 
go  northward  until  the  temperature  of  80°  returns  it  thence.  Is  it 
not  as  if  the  atmosphere  and  the  ocean  were  united  in  marriage, 
and  go  hand  in  hand  to  stand  by  and  to  care  for  each  other,  so 
that  they  may  fulfill  all  their  duties  together  ? 


THE  WINDS.  271 

772.  "  If  a  ship  which  has  conic  into  the  belt  of  cahna,  between 
May  and  September,  can  lie  still  in  tlic  place  where  it  came  into 
this  belt, — cast  anchor  for  example — then  it  would  perceive  a  turn- 
ing of  the  monsoon  or  of  the  trade-wind.  It  would  sec  the  belt 
of  calms  draw  away  to  the  north,  and  afterward  get  the  southwest 
monsoon,  or,  standing  more  westerly,  perhaps  the  southeast  trade. 
On  tlic  contrary,  later  than  September,  this  ship  lying  at  anchor 
will  sec  the  northeast  gradually  awake.  The  belt  of  calms  then 
moves  toward  the  south,  and  removes  from  the  ship  which  re- 
mains tlierc  anchored  on  the  north  side."* 

773.  The  investigations  that  have  taken  place  at  the  Observato- 
ry show  that  the  inliuencc  of  the  land  upon  the  normal  directions 
of  the  wind  at  sea  is  an  immense  influence.  It  is  fre(][uently  traced 
for  a  thousand  miles  or  more  out  upon  the  ocean.  For  instance,  the 
action  of  the  sun's  rays  upon  tlie  great  deserts  and  arid  plains  of 
Africa,  in  the  sunnner  and  autunmal  months,  is  such  as  to  be  felt 
nearly  across  the  iVtlantie  Ocean  between  the  equator  and  the  par- 
allel of  13^  north.  Between  this  parallel  and  the  e{|uator,  the 
northeast  trade-winds,  during  these  seasons,  arc  arrested  in  their 
course  by  the  heated  plains  of  Africa ;  instead  of  "  blowing  homo" 
to  the  C(][uator,  they  stop  and  ascend  over  the  desert  sands  of  the 
continent.  The  southeast  trade-winds,  arriving  at  the  e([uator 
during  this  period,  and  finding  no  northeast  trades  there  to  contest 
their  crossing  the  Ihie,  continue  their  course,  and  blow  hoDic  as  a 
southwest  monsoon  to  the  deserts  where  they  ascend.  These 
southwardly  monsoons  bring  the  rains  which  divide  the  seasons  in 
these  parts  of  the  African  coast.  The  region  of  the  ocean  cm- 
braced  by  these  monsoons  is  cuneiibrm  in  its  shape,  having  its 
base  resting  upon  Africa,  and  its  apex  stretching  over  till  within 
10*^  or  15^  of  the  mouth  of  the  Amazon. 

774.  Indeed,  when  wc  come  to  study  tlie  clTccts  of  South  Amer- 
ica and  Africa  (as  developed  by  the  Wind  and  Current  Charts) 
upon  the  Avinds  at  sea,  we  should  be  led  to  the  conclusion — had 
the  foot  of  civilized  man  never  trod  the  interior  of  these  two  con- 

*  Natuurkiindigo  Bcschrijving  dor  zcccii,  door  M.  F.  Maury,  LTil^-,  Luitcnant 
dcr  Nord-Amorikaanscho  Marine,  vcrtaald  door  M.  II.  Jaiiscn,  Luitcnant  dcr  Zoo. 
(Bijdrago.)     Dordrecht,  P.  K.  Braat.     1855. 


272  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

tinents — that  the  climate  of  one  is  humid ;  that  its  valleys  are, 
for  the  most  part,  covered  with  vegetation,  which  protects  its  sur- 
face from  the  sun's  rays ;  while  the  plains  of  the  other  are  arid 
and  naked,  and,  for  the  most  part,  act  like  furnaces  in  drawing  the 
winds  from  the  sea  to  supply  air  for  the  ascending  columns  which 
rise  from  its  overheated  plains. 

775.  Pushing  these  facts  and  arguments  still  farther,  these  beau- 
tiful and  interesting  researches  seem  already  sufficient  almost  to 
justify  the  assertion  that,  were  it  not  for  the  Great  Desert  of  Sa- 
hara, and  other  arid  plains  of  Africa,  the  western  shores  of  that 
continent,  within  the  trade-wind  region,  would  be  almost,  if  not 
altogether,  as  rainless  and  sterile  as  the  desert  itself. 

776.  Lieutenant  Jansen  has  called  my  attention  to  a  vein  of 
wind  which  forms  a  current  in  the  air  as  remarkable  as  that  of  the 
Gulf;  Stream  is  in  the  sea.  This  atmospherical  Gulf  Stream  is  in 
the  southeast  trade-winds  of  the  Atlantic.  It  extends  from  near 
the  Cape  of  Good  Hope,  in  a  direct  line  to  the  equator,  on  the  me- 
ridian of  Cape  St.  Roque  (Plate  VIII.).  The  homeward  route 
from  the  Cape  of  Good  Hope  lies  in  the  middle  of  this  vein  ;  in  it 
the  winds  are  more  steady  than  in  any  other  part  of  the  Atlantic. 
On  the  edges  of  this  remarkable  aerial  current,  the  wind  is  vari- 
able, and  often  fitful ;  the  homeward-bound  Indiaman  resorts  to 
and  uses  this  stream  in  the  atmosphere  as  the  European-bound 
American  does  the  Gulf  Stream.     It  is  shaded  on  the  Plate. 

777.  These  investigations,  with  their  beautiful  developments, 
eagerly  captivate  the  mind  ;  giving  wings  to  the  imagination,  they 
teach  us  to  regard  the  sandy  deserts,  and  arid  plains,  and  the  in- 
land basins  of  the  earth,  as  compensations  in  the  great  system  of 
atmospherical  circulation.  Like  counterpoises  to  the  telescope, 
which  the  ignorant  regard  as  incumbrances  to  the  instrument, 
these  wastes  serve  as  make-weights,  to  give  certainty  and  smooth- 
ness of  motion — facility  and  accuracy  to  the  workings  of  the  ma- 
chine. ^    • 

778.  When  we  travel  out  upon  the  ocean,  and  get  beyond  the 
influence  of  the  land  upon  the  winds,  we  find  ourselves  in  a  field 
particularly  favorable  for  studying  the  general  laws  of  atmospher- 
ical circulation.     Here,  beyond  the  reach  of  the  great  equatorial 


THE  WINDS. 


273 


and  polar  currents  of  tlie  sea,  there  are  no  unduly  heated  surfaces, 
no  mountain  ranges,  or  other  obstructions  to  the  circulation  of  the 
atmosphere — nothing  to  disturb  it  in  its  natural  courses.  The  sea, 
therefore,  is  the  field  for  observing  the  operations  of  the  general 
laws  which  govern  the  movements  of  the  great  aerial  ocean.  Ob- 
servations on  the  land  will  enable  us  to  discover  the  exceptions. 
But  from  the  sea  we  shall  get  the  rule.  Each  valley,  every  mount- 
ain range  and  local  district,  may  be  said  to  have  its  own  peculiar 
system  of  calms,  winds,  rains,  and  droughts.  But  not  so  the  sur- 
face of  the  broad  ocean  ;  over  it  the  agents  which  are  at  work  are 
of  a  uniform  character. 

779.  Bain-winds  are  the  winds  which  convey  the  vapor  from 
the  sea,  where  it  is  taken  up,  to  other  parts  of  the  earth,  where  it 
is  let  down  either  as  snow,  hail,  or  rain.  As  a  general  rule,  the 
trade- winds  (§  179)  may  be  regarded  as  the  evaporating  winds; 
and  when,  in  the  course  of  their  circuit,  they  are  converted  into 
monsoons,  or  the  variables  of  either  hemisphere,  they  then  gener- 
ally become  also  the  rain- winds — especially  the  monsoons — for  cer- 
tain localities.  Thus  the  southwest  monsoons  of  the  Indian  Ocean 
are  the  rain-winds  for  the  west  coast  of  Hindostan  (§  202).  In  like 
manner,  the  African  monsoons  of  the  Atlantic  are  the  winds  which 
feed  the  springs  of  the  Niger  and  the  Senegal  with  rains. 

780.  Upon  every  water-shed  wdiich  is  drained  into  the  sea,  the 
precipitation,  for  the  whole  extent  of  the  shed  so  drained,  may  be 
considered  as  greater  than  the  evaporation,  by  the  amount  of  wa- 
ter which  runs  off  through  the  river  into  the  sea.  In  this  view,  all 
rivers  may  be  regarded  as  immense  rain-gauges,  and  the  volume 
of  water  annually  discharged  by  any  one,  as  an  expression  of  the 
quantity  which  is  annually  evaporated  from  the  sea,  carried  back 
by  the  winds,  and  precipitated  throughout  the  whole  extent  of  the 
valley  that  is  drained  by  it.  Now,  if  we  knew  the  rain-winds  from 
the  dry,  for  each  locality  and  season  generally  throughout  such  a 
basin,  we  should  be  enabled  to  determine,  with  some  degree  of 
probability  at  least,  as  to  the  part  of  the  ocean  from  which  such 
rains  were  evaporated.  And  thus,  notwithstanding  all  the  eddies 
caused  by  mountain  chains,  and  other  uneven  surfaces,  we  might 
detect  the  general  course  of  the  atmospherical  circulation  over  the 


274  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

land  as  well  as  the  sea,  and  make  the  general  courses  of  circulation 
in  each  valley  as  obvious  to  the  mind  of  the  philosopher  as  is  the 
current  of  the  Mississippi,  or  of  any  other  great  river,  to  his  senses. 

781.  These  investigations  as  to  the  rain- winds  at  sea  indicate 
that  the  vapors  which  supply  the  sources  of  the  Amazon  with  rain, 
are  taken  up  from  the  Atlantic  Ocean  by  the  northeast  and  south- 
east trade-winds ;  and  many  circumstances,  some  of  which  have 
already  been  detailed  (§  389),  tend  to  show  that  the  winds  which 
feed  the  Mississippi  with  rains  get  their  vapor  in  the  southeast 
trade-wind  region  of  the  other  hemisphere.  For  instance,  we  know 
from  observation  that  the  trade-wind  regions  of  the  ocean,  beyond 
the  immediate  vicinity  of  the  land,  are,  for  the  most  part,  rainless 
regions,  and  that  the  trade-wind  zones  may  be  described,  in  a  hy- 
etographic  sense,  as  tjie  evaporating  regions  (§  32).  They  also 
show,  or  rather  indicate,  as  a  general  rule,  that,  leaving  the  polar 
limits  of  the  two  trade- wind  systems,  and  approaching  the  nearest 
pole,  the  precipitation  is  greater  than  the  evaporation  until  the 
point  of  maximum  cold  is  reached. 

782.  And  we  know  also  that,  as  a  general  rule,  the  southeast 
and  northeast  trade-winds,  which  come  from  a  lower  and  go  to  a 
higher  temperature,  are  the  evaporating  winds,  ^.  6.,  they  evaporate 
more  than  they  precipitate ;  while  those  winds  which  come  from 
a  higher  and  go  to  a  lower  temperature  are  the  rain-winds,  ^.  ^., 
they  precipitate  more  than  they  evaporate.  That  such  is  the 
case,  not  only  do  researches  indicate,  but  jeason  teaches,  and  phi- 
losophy intimates. 

783.  These  views,  therefore,  suggest  the  inquiry  as  to  the  suf- 
ficiency of  the  Atlantic,  after  supplying  the  sources  of  the  Amazon 
and  its  tributaries  with  their  waters,  to  supply  also  the  sources  of 
the  Mississippi  and  the  St.  Lawrence,  and  of  all  the  rivers,  great 
and  small,  of  North  America  and  Europe. 

786.  A  careful  study  of  the  rain- winds  (§  32),  in  connection 
with  the  Wind  and  Current  Charts^  will  probably  indicate  to  us 
the  "  springs  in  the  ocean"  which  supply  the  vapors  for  the  rains 
that  are  carried  off  by  those  great  rivers.  "All  the  rivers  run  into 
the  sea ;  yet  tlie  sea  is  not  full ;  unto  the  place  from  whence  the 
rivers  come,  thither  they  return  again." 


THE  WINDS. 


275 


787.  Monsoons  (§  763)  are,  for  the  most  part,  formed  of  trade- 
winds.  When  at  stated  seasons  of  the  year  a  trade-wind  is  de- 
flected in  its  regular  course  from  one  quadrant  to  another,  or  drawn 
in  by  overheated  districts,  it  is  regarded  as  a  monsoon.  Thus  the 
African  monsoons  of  the  Atlantic  (Plate  VIIL),  the  monsoons  of 
the  Gulf  of  ]\Iexico,  and  the  Central  American  monsoons  of  the  Pa- 
cific, are,  for  the  most  part,  formed  of  the  trade-winds,  which  are 
turned  back  or  deflected  to  restore  the  equilibrium  which  the  over- 
heated plains  of  Africa,  Utah,  Texas,  and  New  Mexico  have  dis- 
turbed. When  the  monsoons  prevail  for  five  months  at  a  time, 
for  it  takes  about  a  month  for  them  to  change  and  become  settled, 
then  both  they  and  the  trade-winds,  which  they  replace,  are  called 
monsoons. 

788.  The  northeast  and  the  southwest  monsoons  of  the  Indian 
Ocean  afford  an  example  of  this  kind.  A  force  is  exerted  UT)on 
the  northeast  trade-winds  of  that  sea  by  the  disturbance  which  the 
heat  of  summer  creates  in  the  atmosphere  over  the  interior  plains 
of  Asia,  which  is  more  than  sufficient  to  neutralize  the  forces  which 
cause  those  winds  to  blow  as  trade-winds ;  it  arrests  them ;  and 
were  it  not  for  the  peculiar  conditions  of  the  land  about  that  ocean, 
what  are  now  called  the  northeast  monsoons  would  blow  the  year 
round ;  there  would  be  no  southwest  monsoons  there ;  and  the 
northeast  winds,  being  perpetual,  would  become  all  the  year  what 
in  reality  for  several  months  they  are,  viz.,  northeast  trade-winds. 

789.  As  long  ago  as  1831,  Dove*  maintained  that  the  south- 
west monsoon  was  the  southeast  trade-wind  rushing  forward  to  fill 
the  vacant  places  over  the  Northern  deserts.  Dove  admits  the 
proofs  of  this  to  be  indirect,  and  acknowledges  the  difficulty  of 
finding  out  and  demonstrating  the  problem.! 

790.  I  had  been  studying  the  wind  in  his  circuits,  and  hund- 
reds of  sailors  were  watching  the  vane  for  me,  and  my  good  friend 
Jansen  encouraged  me,  by  his  reasoning  and  suggestions,  to  un- 
dertake the  task  of  proving  this  difficult  proposition  of  ]\Ir.  Dove. 

791.  The  northeast  and  southeast  trade- winds  meet,  we  know 

*  Vide  PoGG,  Ann.  xxi. 

t  Annalen  der  Physik,  No.  94.     Translated  by  Dr.  Rosengarten  for  the  American 
Journal  of  Science,  vol.  xx.,  No.  60. 

S 


276       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

(§  122),  near  the  equator,  where  they  produce  (§  162)  the  belt  of 
equatorial  calms.  All  vessels  that  pass  from  one  system  of  trade- 
winds  to  the  other  have  to  cross  this  calm  belt.  Sometimes  they 
clear  it  in  a  few  hours.  Sometimes  they  are  delayed  in  it  for 
weeks ;  and  the  calm  is  so  still  and  the  rain  so  copious  that  the 
fresh  water  is  sometimes  found  standing  in  pools  on  the  sea. 

792.  If  it  be  true,  as  Dove  maintains,  that  the  southwest  mon- 
soons of  the  Indian  Ocean  are  the  southeast  trade-winds  of  that 
sea  pressing  up  toward  the  desert  regions  of  Asia,  then  a  vessel 
bound  hence  to  Calcutta,  for  instance,  and  entering  the  Indian 
Ocean  at  the  time  of  the  southwest  monsoon,  should  find  no  belt 
of  equatorial  calms  there  at  all,  but,  on  the  contrary,  she  should 
find  the  southeast  trade-wind  to  haul  more  and  more  to  the  south, 
until  finally,  without  having  crossed  any  belt  of  equatorial  calms, 
she  would  find  her  sails  trimmed  to  the  southwest  monsoon. 

793.  In  like  manner,  Jansen  maintains  that  the  northwest 
monsoon  is  a  similar  deflection  of  the  northeast  trade-wind. 

794.  I  had  many  log-books  relating  to  the  Indian  Ocean,  and  I 
had  already,  at  the  commencement  of  my  labors  on  the  Wind  and 
Current  Charts,  essayed  an  examination  into  the  monsoons  of  the 
Indian  Ocean,  but  the  materials  on  hand  at  that  time  proved  insuffi- 
cient. They  have  been  accumulating  ever  since,  and  though  not 
yet  ample  enough  to  settle  definitively  such  a  question,  they  are 
nevertheless  sufficient  to  throw  some  valuable  and  certain  light 
upon  the  subject.  Encouraged  by  Jansen,  and  the  number  of  log- 
books, I  have  recently  put  the  materials  in  the  hands  of  Lieuten- 
ant West  for  co-ordination. 

795.  The  result  is,  they  give  no  indication  of  kwi  calm  belt 
betiveen  the  southeast  trade-wind  and  the  southwest  monsoon  of 
the  Indian  Ocean, 

796.  The  Desert  of  Cobi  and  the  arid  wastes  of  Asia  (§  202) 
are  the  cause  of  these  monsoons.  When  the  sun  is  north  of  the 
equator,  the  force  of  his  rays,  beating  down  upon  these  wide  and 
thirsty  plains,  is  such  as  to  cause  the  vast  superincumbent  body 
of  air  to  expand  and  ascend.  Consequently,  there  is  an  indraught 
of  air  from  the  surrounding  regions  to  supply  the  ascending  col- 
umn.    The  air  that  is  going  to  feed  the  northeast  trades  is  thus 


THE  WINDS.  277 

aiTested,  drawn  in,  heated,  and  caused  to  ascend ;  and  so,  the 
northeast  trade-winds  are  first  weakened,  then  "  killed,"  and  after- 
ward drawn  into  the  vortex  of  ascending  air  over  the  burning 
sands  of  the  deserts ;  on  the  other  hand,  the  southeast  trade- 
wind,  failing,  when  it  arrives  at  the  place  where  the  equatorial 
Doldrums  were  wont  to  be,  to  meet  with  them  or  any  opposing 
force  from  the  northeast  trades,  are  drawn  over  into  the  northern 
hemisphere.  Going  now  from  the  equator  toward  the  poles,  their 
tendency  is  (§  126)  to  obey  the  forces  of  diurnal  rotation,  as  well 
as  those  of  the  indraught  for  the  heated  plains,  and  thus  the  south- 
east trades  become  southwest  monsoons.  In  this  view,  the  "equa- 
torial Doldrums"  of  the  Indian  Ocean  are  transferred,  as  it  were, 
during  the  southwest  monsoons,  to  the  deserts  of  Central  Asia. 

797.  It  may  be  asked  by  some  saying,  Since  we  can  not  always 
tally  the  air,  how  do  we  know  that  these  southwest  monsoons  are 
the  southeast  trades  of  the  Indian  Ocean  ?  The  reply  is,  We  infer 
that  they  are,  because  in  co-ordinating  for  the  Pilot  Chart  of  that 
sea  we  \\2iYQ  foicnd  (§  795)  no  belt  of  ccthns  hetvjeen  the  soiUheast 
trades  and  the  southwest  monsoons^  but  a  gradual  change,  so  to 
speak,  of  the  one  wind  into  the  other.  Thus,  confining  ourselves 
to  August — one  of  the  southwest-monsoon  months — and  to  the 
strip  of  ocean  between  85°  and  90°  east,  the  investigation  gives 
as  follows  for  calms  and  winds  in  the  field  between : 

10°  S.  and    5°  S.  133  observations.  0  calms.  Wind  S.E. 

5°  S.  and    0°        102  "  3     "  "     S. 

0°       and    5°  N.    99  "  3     "  "     S.W. 

5°  N.  and  10°  N.    77  "  0     "  "     S.W. 

798.  These  monsoons  do  not,  as  we  are  generally  taught  to 
suppose,  commence  or  end  at  the  same  time  all  over  the  Indian 
Ocean. 

799.  The  Pilot  Charts  (Plate  V.)  have  brought  this  fact  out  in 
very  bold  relief.  Take,  as  an  illustration,  the  strip  of  ocean  be- 
tween the  meridians  of  85°  and  90°  east,  south  of  Calcutta,  and 
as  far  as  the  equator.  Let  us  divide  it  into  "fields"  (Plate  V.), 
by  drawing  across  it  lines  to  represent  the  parallels  of  5°,  10°, 
15°,  and  20°  north. 

800.  In  the  first  field  below  Calcutta,  ^.  e.^  between  the  land 


278  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

and  20°  north,  tlie  northeast  trade-winds,  toward  the  latter  part 
of  January,  begin  their  conflict  with  the  southwest  monsoons. 
The  conflict  rages  in  February,  and  by  March  the  southwest  mon- 
soons in  that  "field"  are  considered  to  have  regularly  set  in. 
They  now  remain  the  dominant  wind  for  upward  of  six  months, 
and  until  some  time  in  the  early  part  of  September.  The  north- 
east monsoons  or  trades  now  renew  the  conflict,  which  is  carried 
on  with  more  and  more  vigor  until  the  latter  part  of  November, 
when  they  obtain  the  ascendency,  and  prevail  until  the  latter  part 
of  January,  Avhen,  as  before  stated,  the  southwest  monsoons  com- 
mence their  annual  struggle  for  the  mastery. 

801.  In  the  next  field  below,  i.  e.,  between  15°  and  20°  north 
latitude,  the  northeast  monsoons  begin  to  grow  light  and  variable, 
and  to  have  conflicts  with  the  southwest  in  February.  The  pe- 
riod of  this  conflict,  or  change,  as  it  is  called,  frequently  lasts  until 
some  time  in  March,  when  the  force  that  is  calling  in  and  driving 
the  monsoons  from  the  southwest  finally  gains  the  ascendant. 
They  then  blow  steadily  until  late  in  September,  when  the  north- 
east trade-wind  forces  begin  again  to  assert  their  ascendency  and 
to  renew  the  conflict  on  this  side  through  October,  by  which  time 
the  northeast  trades  or  monsoons  become  the  prevailing  winds. 
Thus,  by  going  two  or  three  hundred  miles  farther  from  the  sup- 
posed place  of  heat  and  rarefaction  that  give  rise  to  this  system  of 
winds,  the  duration  of  the  northeast  monsoons  is  prolonged  nearly 
a  month ;  for  in  this  "  field"  they  prevail  from  November  to  Janu- 
ary inclusive,  three  months,  while  the  southwest  last  from  about 
the  middle  of  March  to  the  middle  of  September,  say  six  months. 

802.  In  the  next  field  below,  i.  e.,  between  the  parallels  of  10° 
and  15°,  the  southwest  monsoons  blow  about  five  months,  per- 
haps not  quite  so  long ;  they  do  not  commence  as  early,  nor  blow 
so  late  as  in  the  "  field"  above.  They  begin  the  conflict  with  the 
northeast  trade-wind  forces  in  the  latter  part  of  March,  and  gain 
the  ascendant  in  May.  They  then  prevail  till  October,  when  the 
northeast  trade-wind  forces,  escaping  from  the  heated  plains  of  the 
interior,  begin  to  renew  the  annual  combat  which  is  to  get  them 
the  victory.  They  soon  achieve  it,  and  maintain  the  mastery  un- 
disputed till  the  last  of  March  or  first  of  April. 


THE  WINDS. 


279 


803.  In  the  next  field  below,  namely,  that  between  5°  and  10^ 
N.,  the  northeast  trades  or  monsoons  do  not  begin  to  feel  the  heat- 
ing-iip  of  the  deserts  until  the  month  of  April  has  set  in.  The 
battle  now,  as  it  may  well  be  supposed,  is  not  to  last  long,  for  the 
sun  is  vigorously  at  work  heating-up  the  brown  wastes,  and  call- 
ing upon  the  northeast  trades  to  stop  and  supply  the  ascending 
column  with  fresh  air.  By  the  end  of  April  the  southwest  mon- 
soons are  found  to  be  decidedly  in  the  ascendant,  and  they  so  con- 
tinue for  nearly  five  months.  In  October,  but  not  before  the  mid- 
dle, the  conflict  again  commences ;  feebly  at  first,  and  by  fitful  G:usts 
it  rages  all  through  November,  and  is  not  fairly  over  before  the 
end  of  December.  Here  sims  of  the  southeast  trade-winds  bedn 
to  appear.  They  come  in  on  the  side,  now  of  the  northeast,  now 
of  the  southwest  monsoons,  and  so  prolong  the  contest. 

804.  In  the  next  "field" — between  0°  and  5°  N. — the  southwest 
monsoon  is  decidedly  marked  only  for  a  short  time.  This  con- 
flict ends  in  May,  the  other  begins  in  August,  leaving  the  north- 
east trade-winds  decidedly  in  the  ascendant  for  only  about  three 
months,  January  to  March.  So  that  in  this  "field"  we  have  dur- 
ing the  year  six  months  of  conflicting  winds,  and  three  months 
only  for  each  monsoon. 

805.  If  a  ship  were  stationed  in  each  one  of  these  five  "  fields," 
to  observe  the  setting  in,  continuance,  and  changing  of  the  mon- 
soons, the  one  in  the  northern  "field,"  between  the  land  and  20° 
N".,  would  report  that  the  southwest  monsoons  had  been  observed 
to  have  regularly  set  in  before  the  first  of  March,  after  a  conflict 
which  lasted  perhaps  six  weeks.  The  observer  in  the  next  "field" 
below,  i.  e.,  between  15°  and  20°  N.,  would  report  that  he  found 
the  southwest  monsoons  to  set  in  about  the  middle  of  March,  and 
after  a  conflict  that  commenced  in  ^February  instead  of  January,  as 
in  the  "  field"  above.  The  vessel  in  the  "field"  next  below — 10^ 
and  15° — would  report  them  early  in  May,  after  a  conflict  of  four 
or  five  weeks.  The  ship  between  5°  and  10°  would  not  find 
them  to  set  in  regularly  until  the  first  of  May,  and  still  later  would 
the  vessel  in  the  last  "  field"— 0°  and  5°  K— report  them.  Thus 
we  perceive  that  the  southwest  monsoons  extend  from  the  land 
out  to  the  sea  at  a  progressive  rate,  and  that  they  spread  firom  a 


280       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

centre  or  point  like  a  circle  on  the  water.  According  to  the  Pilot 
Chart,  which  gives  11,800  observations  for  the  five  "helds"  above, 
the  march  of  the  southwest  monsoons  from  Calcutta  toward  the 
equator  is  at  the  rate  of  15  or  20  miles  a  day. 

806.  In  other  words,  if  a  vessel  in  latitude  23°  N.,  between  the 
meridians  85°  and  90°  E.,  were  to  commence  about  the  first  of 
March  to  steer  due  south,  and  sailed  15  or  20  miles  a  day  on  that 
course  till  she  reached  the  equator,  she  would,  at  the  end  of  each 
day's  sail,  arrive  with  the  regular  setting  in  of  the  southwest  mon- 
soons at  that  place. 

807.  We  thus  perceive  how  a  desert  land  spreads  its  influence 
through  the  distance  upon  the  winds.  The  first  effects  of  heating 
up  the  plains  are  necessarily  felt  by  the  air  nearest  at  hand,  and 
by  that  farther  off  at  a  later  period,  so  that  the  southwest-mon- 
soon influence  is  in  this  part  of  the  ocean  propagated  from  the  land 
out  upon  the  sea  at  the  rate  above  stated. 

808.  Of  course,  the  vast  plains  of  Asia  are  not  brought  up  to 
monsoon  heat  jper  saltmn,  or  in  a  day.  They  require  time  both 
to  be  heated  up  to  this  point  and  to  be  cooled  down  again. 

809.  The  monsoon  season  may  be  always  known  by  referring 
to  the  cause  which  produces  these  winds.  Thus,  by  recollecting 
where  the  thirsty  and  overheated  plains  are  which  cause  the  mon- 
soons, we  know  at  once  that  these  winds  are  rushing  with  great- 
est force  toward  these  plains  at  the  time  that  is  the  hottest  season 
of  the  year  upon  them. 

810.  The  influence  of  these  heated  plains  upon  the  Tvinds  at 
sea  is  felt  for  a  thousand  miles  or  more.  Thus,  though  the  Desert 
of  Cobi  and  the  sun-burned  plains  of  Asia  are,  for  the  most  part, 
north  of  latitude  30°,  their  influence  in  making  monsoons  (§  797)  is 
felt  south  of  the  equator  (Plate  VIII.).  So,  too,  with  the  great  Des- 
ert of  Sahara  and  the  African  monsoons  of  the  Atlantic ;  also,  with 
the  Salt  Lake  country  and  the  ]\Iexican  monsoons  on  one  side, 
and  those  of  Central  America  in  the  Pacific  on  the  other.  The 
influence  (§  202)  of  the  deserts  of  Arabia  upon  the  Avinds  is  felt  in 
Austria  and  other  parts  of  Europe,  as  the  observations  of  Kriel, 
Lamont,  and  others  show. 

811.  So,  also,  do  the  islands,  such  as  the  Society  and  Sand- 


THE  WINDS.  281 

wicli,  that  stand  far  away  from  any  large  extent  of  land,  have  a 
very  singular  but  marked  effect  upon  the  wind.  They  interfere 
with  the  trades  very  often,  and  turn  them  back ;  for  westerly  and 
equatorial  winds  are  common  at  both  these  groups,  in  their  winter 
time.  Some  hydrographers  have  taken  those  westerly  winds  of 
the  Society  Islands  to  be  an  extension  of  the  monsoons  of  the  In- 
dian Ocean.  Not  so :  they  are  local,  and  do  not  extend  a  great 
way  either  from  the  Sandwich  or  Society  Islands. 

That  they  are  local  about  the  former  group,  an  examination  of 
sheet  No.  5,  Pilot  Chart  North  Pacific,  will  instantly  show. 

812.  It  is  a  curious  thing  is  this  influence  of  islands  in  the 
trade-wind  region  upon  the  winds  in  the  Pacific.  Every  naviga- 
tor who  has  cruised  in  those  parts  of  that  ocean  has  often  turned 
with  wonder  and  delight  to  admke  the  gorgeous  piles  of  cumuli, 
heaped  up  and  arranged  in  the  most  delicate  and  exquisitely  beau- 
tiful masses  that  it  is  possible  for  fleecy  matter  to  assume.  Not 
only  are  these  piles  found  capping  the  hills  among  the  islands,  but 
they  are  often  seen  to  overhang  the  lowest  islet  of  the  tropics,  and 
even  to  stand  above  coral  patches  and  hidden  reefs,  "a  cloud  by 
day,"  to  serve  as  a  beacon  to  the  lonely  mariner  out  there  at  sea, 
and  to  warn  him  of  shoals  and  dangers  which  no  lead  nor  seaman's 
eye  has  ever  seen  or  sounded  out. 

813.  These  clouds,  under  favorable  circumstances,  may  be  seen 
gathering  above  the  low  coral  island,  and  performing  their  office 
in  preparing  it  for  vegetation  and  fruitfulness  in  a  very  striking 
manner.  As  they  are  condensed  into  showers,  one  fancies  that 
they  are  a  sponge  of  the  most  exquisite  and  delicately  elaborated 
material,  and  that  he  can  see,  as  they  "  drop  down  their  fatness," 
the  invisible  but  bountiful  hand  aloft  that  is  pressing  and  squeez- 
ing it  out. — Maury's  Sailing  Directions^  7th  ed.,  p.  820. 

814.  It  would  appear,  therefore,  that  these  desert  countries  ex- 
ercise a  powerful  influence  in  checking  and  overcoming  the  force 
of  the  northeast  trade-winds.  There  are  no  such  extensive  influ- 
ences at  work  checking  the  southeast  trades.  On  the  contrary, 
these  are  accelerated ;  for  the  same  forces  that  serve  to  destroy  the 
northeast  trade-winds,  or  retard  them,  tend  also  to  draw  the  south- 
east trade-winds  on,  or  to  accelerate  them.     Hence  the  ability  of 


282       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

the  southeast  trade-winds  to  push  themselves  over  into  the  north- 
ern hemisphere. 

815.  Hence,  also,  we  infer  that,  between  certain  parallels  of  lat- 
itude in  the  northern  hemisphere,  the  sun's  rays,  by  reason  of  the 
great  extent  of  land  surface,  operate  with  much  more  intensity 
than  they  do  between  corresponding  parallels  in  the  southern ;  and 
that,  consequently,  the  mean  summer  temperature  on  shore,  north 
of  the  equator,  is  higher  than  it  is  south :  a  beautiful  physical  fact 
which  the  winds  have  revealed,  in  corroboration  of  what  observa- 
tions with  the  thermometer  had  already  induced  meteorologists  to 
suspect. 

816.  It  appears,  from  what  has  been  said,  that  it  is  the  rays 
of  the  sun  operating  upon  the  land,  not  upon  the  w^ater,  which 
causes  the  monsoons.  Now  let  us  turn  to  Plate  YIIL,  and  ex- 
amine into  this  view.  The  monsoon  regions  are  marked  with  half 
bearded  and  half  feathered  arrows ;  and  we  perceive,  looking  at 
the  northern  hemisphere,  that  all  of  Europe,  some  of  Africa,  most 
of  Asia,  and  nearly  the  whole  of  North  America,  are  to  the  north, 
or  on  the  polar  side  of  the  northeast  trade-wind  zone  ;  whereas  but 
a  small  part  of  Australia,  less  of  South  America,  and  still  less  of 
South  Africa,  are  situated  on  the  polar  side  of  the  zone  of  south- 
east trade-winds.  In  other  words,  there  are,  on  the  polar  side  of 
the  southeast  trade-winds,  no  great  plains,  except  in  Australia, 
upon  which  the  rays  of  the  sun,  in  the  summer  of  the  other  hem- 
isphere, can  play  with  force  enough  to  rarefy  the  air  sufficiently 
to  materially  interrupt  these  winds  in  their  course.  But,  besides 
the  vast  area  of  such  plains  in  the  northern  hemisphere, ,  on  the 
polar  side  of  its  trade-wind  belt,  the  heat  of  which  is  sufficient  (§ 
810)  to  draw  these  trade-winds  back,  there  are  numerous  other 
districts  in  the  extra-tropical  regions  of  our  hemisphere  the  sum- 
mer heat  of  which,  though  it  be  not  sufficient  to  turn  the  north- 
east trade-winds  back,  and  make  a  monsoon  of  them,  yet  may  be 
sufficient  to  weaken  them  in  their  force,  and  by  retarding  them  (§ 
815),  draw  the  southeast  trade- winds  over  into  the  northern  hem- 
isphere. 

817.  Now,  as  this  interference  from  the  land  takes  place  in  the 
summer  only,  we  might  infer,  without  appealing  to  actual  observa- 


THE  WINDS.  283 

tion,  that  the  position  of  these  trade-wind  zones  is  variable  ;  that 
is,  that  the  equatorial  edge  of  the  southeast  trade-wind  zone  is  far- 
ther to  the  north  in  our  summer,  when  the  northeast  trades  are 
most  feeble,  than  it  is  in  winter,  when  they  are  strongest. 

818.  We  have  here,  then,  at  work  upon  these  trade- wind  zones, 
a  force  now  weak,  now  strong,  which,  of  course,  would  cause  these 
zones  to  vibrate  up  and  down  the  ocean,  and  within  certain  lim- 
its, according  to  the  season  of  the  year.  These  limits  are  given 
on  Plate  VIII.  for  spring  and  autumn.  During  the  latter  season 
these  zones  reach  their  extreme  northern  declination,  and  in  our 
spring  their  utmost  limits  toward  the  south. 

819.  Changing  of  the  Monsoons. — Lt.  Jansen,  in  his  appendix 
to  the  Dutch  edition  of  this  work,  thus  describes  this  phenomenon : 

"We  have  seen  (§  262)  that  the  calms  which  precede  the  sea- 
breeze  generally  continue  longer,  and  are  accompanied  with  an 
upward  motion  of  the  air ;  that,  on  the  contrary,  those  which  pre- 
cede the  land-breeze  are,  in  the  Java  Sea,  generally  of  shorter 
duration,  accompanied  by  a  heavy  atmosphere,  and  that  there  is 
also  an  evident  difference  between  the  conversion  of  the  land- 
breeze  into  the  sea-breeze,  and  of  the  latter  into  the  former. 

820.  "  Even  as  the  calms  vary,  so  there  appears  to  be  a  marked 
difference  between  the  changing  of  the  monsoons  in  the  spring  and 
in  the  autumn  in  the  Java  Sea.  As  soon  as  the  sun  has  crossed 
the  equator,  and  its  vertical  rays  begin  to  play  more  and  more 
perpendicularly  upon  the  northern  hemisphere,  the  inland  plains 
of  Asia,  North  Africa,  and  of  IvTorth  America  are  so  heated  as  to 
give  birth  to  the  southwest  monsoons  in  the  China  Sea,  in  the 
North  Indian  Ocean,  in  the  North  Atlantic,  and  upon  the  west 
coast  of  Central  America:  then  the  northwest  monsoon  disap- 
pears from  the  East  Indian  Archipelago,  and  gives  place  to  the 
southeast  trade-wind,  which  is  known  as  the  east  monsoon,  just 
as  the  northwest  wind,  which  prevails  during  the  southern  sum- 
mer, is  called  the  west  monsoon. 

821.  "  This  is  the  only  northwest  monsoon  which  is  found  in 
the  southern  hemisphere.  While  in  the  northern  hemisphere  the 
northeast  trade-wind  blows  in  the  China  Sea  and  in  the  Indian 
Ocean,  in  the  East  Indian  Archipelago  the  west  monsoon  prevails ; 


284  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

and  when  here,  the  southeast  trade  blows  as  the  east  monsoon,  we 
find  the  southwest  monsoon  in  the  adjacent  seas  of  the  northern 
hemisphere.  Generally  the  westerly  monsoons  blow  during  the 
summer  months  of  the  hemisphere  wherein  they  are  found. 

822.  "As  the  land-breeze  daily  destroys  in  miniature  the  regu- 
lar flow  of  the  trade-wind,  so  does  the  latter  the  west  monsoon  in 
larger  measure,  and  observations  will  be  able  to  decide  whether 
monthly  disturbances  do  not  also  take  place. 

823.  "  In  the  Java  Sea,  during  the  month  of  February,  the  west 
monsoon  blows  strong  almost  continually ;  in  March  it  blows  in- 
termittingly,  and  with  hard  squalls ;  but  in  April  the  squalls  be- 
come less  frequent  and  less  severe.  Now  the  changing  commen- 
ces ;  all  at  once  gusts  begin  to  spring  up  from  the  east :  they  are 
often  followed  by  calms.  The  clouds  which  crowd  themselves 
upon  the  clear  sky  give  warning  of  the  combat  in  the  upper  air 
which  the  currents  there  are  about  to  wage  with  each  other. 

824.  "  The  electricity,  driven  thereby  out  of  its  natural  channels, 
in  which,  unobserved,  it  has  been  performing  silently,  but  with  the 
full  consciousness  of  its  power,  the  mysterious  task  appointed  to 
it,  now  displays  itself  with  dazzling  majesty ;  its  sheen  and  its 
voice  fill  with  astonishment  and  deep  reverence  the  mind  of  the 
sailor — so  susceptible,  in  the  presence  of  storm  and  darkness,  to 
impressions  that  inspire  feelings  both  of  dread  and  anxiety,  which 
by  pretended  occupations  he  strives  in  vain  to  conceal.* 

825.  "Day  and  night  we  now  have  thunder-storms.  The  clouds 
are  in  continual  movement,  and  the  darkened  air,  laden  with  vapor, 
flies  in  all  directions  through  the  skies.  The  combat  which  the 
clouds  seem  to  court  and  to  dread  appears  to  make  them  more 
thirsty  than  ever.  They  resort  to  extraordinary  means  to  refresh 
themselves ;  in  tunnel  form,  when  time  and  opportunity  fail  to 
allow  them  to  quench  their  thirst  from  the  surrounding  atmos- 
phere in  the  usual  manner,  they  descend  near  the  surface  of  the 
sea,  and  appear  to  lap  the  water  directly  up  with  their  black 
mouths.  Water-spouts,  thus  created,  are  often  seen  in  the  chang- 
ing season,  especially  among  small  groups  of  islands  which  appear 

*  No  phenomena  in  nature  make  a  deeper  impression  upon  the  sailor  than  a  dark 
thunder-storm  in  a  calm  at  sea. — Jan  sen. 


THE  WINDS.  285 

to  facilitate  tlieir  formation.*  The  water- spouts  are  not  always 
accompanied  hy  strong  winds ;  frequently  more  than  one  is  seen 
at  a  time,  whereupon  the  clouds  whence  they  proceed  disperse  in 
various  directions,  and  the  ends  of  the  water-spouts  bending  over 
finally  causes  them  to  break  in  the  middle,  although  the  water 
which  is  now  seen  foaming  around  their  base  has  suffered  little 
or  no  movement  laterally. 

826.  "Yet  often  the  wind  prevents  the  formation  of  water-spouts. 
In  their  stead  the  wind-spout  shoots  up  like  an  arrow,  and  the 
sea  seems  to  try  in  vain  to  keep  it  back.  The  sea,  lashed  into 
fury,  marks  with  foam  the  path  along  which  the  conflict  rages,  and 
roars  with  the  noise  of  its  water-spouts  ;  and  woe  to  the  rash  mar- 
iner who  ventures  therein  !| 

"The  height  of  the  spouts  is  usually  somewhat  less  than  200 
yards,  and  their  diameter  not  more  than  20  feet,  yet  they  are  often 
taller  and  thicker ;  when  the  opportunity  of  correctly  measuring 
them  has  been  favorable,  however,  as  it  generally  was  when  they 
passed  between  the  islands,  so  that  the  distance  of  their  bases 
could  be  accurately  determined,  I  have  never  found  them  higher 
than  700  yards,  nor  thicker  than  50  yards.  In  October,  in  the 
Archipelago  of  Rhio,  they  travel  from  southwest  to  northeast. 
They  seldom  last  longer  than  five  minutes ;  generally  they  are 
dissipated  in  less  time.  As  they  are  going  away,  the  bulbous 
tube,  which  is  as  palpable  as  that  of  a  thermometer,  becomes 
broader  at  the  base,  and  little  clouds,  like  steam  from  the  pipe  of 
a  locomotive,  are  continually  thrown  off  from  the  circumference  of 
the  spout,  and  gradually  the  water  is  released,  and  the  cloud 
whence  the  spout  came  again  closes  its  mouth,  j: 

*  I  never  saw  more  water-spouts  than  in  the  Archipelago  of  Bioun  Singen,  during 
the  changing.     Almost  daily  we  saw  one  or  more. — Jansen. 

t  The  air-spouts  near  the  equator  always  appear  to  me  to  be  more  dangerous  than 
the  water-spouts.  I  have  once  had  one  of  the  latter  to  pass  a  ship's  length  ahead  of 
me,  but  I  perceived  little  else  than  a  waterfall  in  which  I  thought  to  come,  yet  no 
wind.  Yet  the  water-spouts  there  also  are  not  to  be  trusted.  I  have  seen  such 
spouts  go  up  out  of  the  water  upon  the  shore,  where  they  overthrew  strong  isolated 
frame-houses.  I  have,  however,  never  been  in  a  situation  to  observe  in  what  direc- 
tion they  revolved. — Jansen. 

I  Miniature  water-spouts  may  be  produced  artificially  by  means  of  electricity,  and 
those  in  nature  are  supposed  to  be  caused  by  the  display  of  electrical  phenomena. 


286  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

827.  "  During  the  changing  of  the  monsoons,  it  is  mostly  calm 
or  cool,  with  gentle  breezes,  varied  with  rain-storms  and  light  gales 
from  all  points  of  the  compass.  They  are  harassing  to  the  crew, 
who,  with  burning  faces  under  the  clouded  skies,*  impatiently 
trim  the  sails  to  the  changing  winds.  However,  the  atmosphere 
generally  becomes  clear,  and,  contrary  to  expectation,  the  north- 
east wind  comes  from  a  clear  sky ;  about  the  coming  of  the  mon- 
soon it  is  northerly.  Now  the  clouds  are  again  packed  together ; 
the  wind  dies  away,  but  it  will  soon  be  waked  up  to  come  again 
from  another  point.  Finally,  the  regular  land  and  sea  breezes 
gradually  replace  rain,  and  tempests,  calms,  and  gentle  gales.    The 

"  From  the  conductor  of  an  electrical  machine,"  says  Dr.  Bonzano,  of  New  Orleans, 
*'  suspend  by  a  wire  or  chain  a  small  metallic  ball  (one  of  wood  covered  with  tin- 
foil), and  under  the  ball  place  a  rather  wide  metallic  basin  containing  some  oil  of  tur- 
pentine, at  the  distance  of  about  three  quarters  of  an  inch.  If  the  handle  of  the  ma- 
chine be  now  turned  slowly,  the  liquid  in  the  basin  will  begin  to  move  in  different  di- 
rections, and  form  whirlpools.  As  the  electricity  on  the  conductor  accumulates,  the 
troubled  liquid  will  elevate  itself  in  the  centre,  and  at  last  become  attached  to  the 
ball.  Draw  off  the  electricity  from  the  conductor  to  let  the  liquid  resume  its  position : 
a  portion  of  the  turpentine  remains  attached  to  the  ball.  Turn  the  handle  again  very 
slowly,  and  observe  now  the  few  drops  adhering  to  the  ball  assume  a  conical  shape, 
with  the  apex  downward,  while  the  liquid  under  it  assumes  also  a  conical  shape,  the 
apex  upward,  until  both  meet.  As  the  liquid  does  not  accumulate  on  the  ball,  there 
must  necessarily  be  as  great  a  current  downward  as  upward,  giving  the  column  of  li- 
quid a  rapid  circular  motion,  yhich  continues  until  the  electricity  from  the  conductor 
is  nearly  all  discharged,  silently,  or  until  it  is  discharged  by  a  spark  descending  into 
the  Hquid.  The  same  phenomena  take  place  with  oil  or  water.  Using  the  latter 
liquid,  the  ball  must  be  brought  much  nearer,  or  a  much  greater  quantity  of  electric- 
ity is  necessary  to  raise  it. 

"  If,  in  this  experiment,  we  let  the  ball  swing  to  and  fro,  the  little  water-;spout  will 
travel  over  its  miniature  sea,  carrying  its  whirlpools  along  with  it.  When  it  breaks 
up,  a  portion  of  the  liquid,  and  with  it  any  thing  it  may  contain,  remains  attached  to 
the  ball.  The  fish,  seeds,  leaves,  etc.,  etc.,  that  have  fallen  to  the  earth  in  rain-squalls, 
may  have  owed  their  elevation  to  the  clouds  to  the  same  cause  that  attaches  a  few 
drops  of  the  liquid,  with  its  particles  of  impurities,  to  the  ball." 

By  reference  to  Plate  XIII.,  we  see  that  the  phenomenon  of  thunder  and  lightning 
is  of  much  more  frequent  occurrence  in  the  North  than  in  the  South  Atlantic  ;  and  I 
infer  that  we  have  more  electrical  phenomena  in  the  northern  than  in  the  southern 
hemisphere.  Do  water-spouts  occur  on  one  side  of  the  equator  more  frequently  than 
they  do  on  the  other  1  I  have  cruised  a  great  deal  on  the  southern  hemisphere,  and 
never  saw  a  water-spout  there.  According  to  the  log-books  at  the  Observatory,  they 
occur  mostly  on  the  north  side  at  the  equator. — M. 

*  At  sea  the  face  and  hands  burn  (change  the  skin)  much  quicker  under  a  clouded 
than  under  a  clear  sky. — Jansen. 


THE  WINDS. 


287 


rain  holds  up  during  the  day,  and  in  the  Java  Sea  we  have  the 
east  monsoon.  It  is  then  Maj.  Farther  to  the  south  than  the 
Java  Sea  the  east  monsoon  commences  in  ApriL* 

828.  "This  monsoon  prevails  till  September  or  October,  when 
it  turns  to  become  the  west  monsoon.  It  has  seemed  to  me  that 
the  east  monsoon  does  not  blow  the  same  in  every  month  (§  851) ; 
that  its  direction  becomes  more  southerly,  and  its  power  greater 
after  it  has  prevailed  for  some  time.j 

829.  "  It  is  sufficiently  important  to  fix  the  attention,  seeing  that 
these  circumstances  have  great  influence  upon  the  winds  in  the 
many  straits  of  the  Archipelago,  in  which  strong  currents  run  most 
of  the  time.  Especially  in  the  straits  to  the  east  of  Java,  these 
currents  are  very  strong.  I  have  been  unable  to  stem  the  current 
with  eight-mile  speed.  However,  they  do  not  always  flow  equal- 
ly strong,  nor  always  in  the  same  direction.  They  are  probably 
the  strongest  when  the  tidal  current  and  the  equatorial  current 
meet  together.  It  is  said  that  the  currents  in  the  straits  during 
the  east  monsoon  run  eighteen  hours  to  the  north,  and  six  hours 
to  the  south,  and  the  reverse  during  the  west  monsoon.  The 
passing  of  the  meridian  by  the  moon  appears  to  be  the  fixed  point 
of  time  for  the  turning  of  the  currents.  It  is  probable  that  the 
heated  water  of  the  Archipelago  is  discharged  to  the  north  during 
the  east  monsoon,  and  to  the  south  during  the  west  monsoon. 

830.  "As  the  sea  makes  the  coming  of  the  southern  summer 
known  to  the  inhabitants  of  the  Java  coast,t  the  turning  of  the 
east  monsoon  into  the  west  monsoon  commences.  After  the  sun 
has  finished  its  yearly  task  in  the  northern  hemisphere,  and  brings 

*  In  the  northeast  part  of  the  Archipelago  the  east  monsoon  is  the  rainy  monsoon. 
The  phenomena  in  the  northeast  part  are  thus  wholly  different  from  those  in  the  Java 
Sea. — Jansen. 

t  As  is  well  known,  the  Strait  of  Soerabaya  forms  an  elbow  whose  easterly  outlet 
opens  to  the  east,  while  the  westerly  outlet  opens  to  the  north.  In  the  beginning  of 
the  east  monsoon  the  sea-wind  (east  monsoon)  blows  through  the  westerly  entrance 
as  far  as  Grissee  (in  the  elbow) ;  in  the  latter  part  of  this  monsoon,  the  sea-wind 
blows,  on  the  contrary,  through  the  easterly  entrance  es  far  as  Sambilangan  (the  nar- 
row passage  where  the  westerly  outlet  opens  into  the  sea). — Jansen. 

t  In  the  Archipelago  we  have  generally  high  water  but  once  a  day,  and,  with  the 
equinoxes,  the  tides  also  turn.  The  places  which  have  high  water  by  day  in  one 
monsoon  get  it  at  night  in  the  other. — Jansen. 


288       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

its  powerful  influence  to  operate  in  the  southern  hemisphere,  a 
change  is  at  once  perceived  in  the  constant  fine  weather  of  the  east 
monsoon  of  the  Java  Sea.  As  soon  as  it  is  at  its  height  upon  the 
Java  Sea  (6°  south),  then  the  true  turning  of  the  monsoon  begins, 
and  is  accomplished  much  more  rapidly  than  the  spring  turning. 
The  calms  then  are  not  so  continuous.  The  combat  in  the  upper 
atmosphere  appears  to  be  less  violent ;  the  southeast  trade,  which 
has  blown  as  the  east  monsoon,  does  not  seem  to  have  sufficient 
strength  to  resist  the  aggressors,  who,  with  wild  storms  from  the 
northwest  and  west,  make  their  superiority  known.  Upon  and 
in  the  neighborhood  of  the  land,  thunder-storms  occur,  but  at  sea 
they  are  less  frequent. 

831.  "The  atmosphere,  alternately  clear  and  cloudy,  moves  more 
definitely  over  from  the  northwest,  so  that  it  appears  as  if  no  com- 
bat was  there  waged,  and  the  southeast  gives  place  without  a 
contest. 

832.  "  The  land-breezes  become  less  frequent,  and  the  phenom- 
ena by  day  and  by  night  become,  in  a  certain  sense,  more  accord- 
ant with  each  other.  Storms  of  wind  and  rain  beneath  a  clouded 
sky  alternate  with  severe  gales  and  steady  winds.  In  the  last  of 
November  the  west  monsoon  is  permanent. 

833.  "  Such  are  the  shiftings.  But  what  have  they  to  do  with 
the  general  system  of  the  circulation  of  the  atmosphere?  When- 
ever we  read  attentively  the  beautiful  meditations  of  the  founder 
of  the  Meteorology  of  the  Sea,  and  follow  him  in  the  development 
of  his  hypothesis,  which  lays  open  to  view  the  wheels  whereby  the 
atmosphere  performs  its  varied  and  comprehensive  task  with  order 
and  regularity,  then  it  will  not  be  necessary  to  furnish  proof  that 
these  turnings  are  nothing  else  than  the  passing  of  a  belt  of  calms 
which  separates  the  monsoons  from  each  other,  and  which,  as  we 
know,  goes  annually  with  the  sun  from  the  south  to  the  north, 
and  back  over  the  torrid  zone  to  and  fro. 

834.  "  So  also  the  calms,  which  precede  the  land  and  sea  winds, 
are  turned  back.  If,  at  the  coming  of  the  land-wind  in  the  hills, 
we  go  with  it  to  the  coast — to  the  sea,  we  shall  perceive  that  it 
shoves  away  the  calms  which  preceded  it  from  the  hills  to  the 
coast,  and  so  far  upon  the  sea  as  the  land-wind  extends.     Here, 


THE  WINDS.  289 

Upon  the  limits  of  the  permanent  monsoon,  the  place  for  the  calms 
remains  for  the  night,  to  be  turned  back  to  the  land  and  to  the 
hills  the  following  day  by  the  sea-wind.  In  evely  place  where 
these  calms  go,  the  land  and  sea  winds  turn  back.  If  various  ob- 
servers, placed  between  the  hills  and  the  sea,  and  between  the  coast 
and  the  farthest  limit  of  the  land-wind,  noted  the  moment  when 
they  perceived  the  calms,  and  that  when  they  perceived  the  land- 
wind,  then  by  this  means  they  would  learn  how  broad  the  belt  of 
calms  has  been,  and  with  what  rapidity  they  are  pushed  over  the 
sea  and  over  the  land.  And  even  though  the  results  one  day 
should  be  found  not  to  agree  very  well  with  those  of  another,  they 
would  at  least  obtain  an  average  thereof  which  would  be  of  value. 
So,  on  a  larger  scale,  the  belt  of  calms  which  separates  the  mon- 
soons from  each  other,  presses  in  the  spring  from  the  south  to  the 
north,  and  in  the  fall  from  the  north  to  the  south,  and  changes 
the  monsoons  in  every  place  where  it  presses."* 

835.  The  Calm  Belts. — There  is  between  the  two  systems  of 
trade-winds  a  region  of  calms,  known  as  the  equatorial  calms.  It 
has  a  mean  average  breadth  of  about  six  degrees  of  latitude.  In 
this  region,  the  air  which  is  brought  to  the  equator  by  the  north- 
east and  southeast  trades  ascends.  This  belt  of  calms  always 
separates  these  two  trade-wind  zones,  and  travels  up  and  down 
with  them.  If  we  liken  this  belt  of  equatorial  calms  to  an  im- 
mense atmospherical  trough,  extending,  as  it  does,  entirely  around 
the  earth,  and  if  we  liken  the  northeast  and  southeast  trade-winds 
to  two  streams  discharging  themselves  into  it,  we  shall  see  that 
we  have  two  currents  perpetually  running  in  at  the  bottom,  and 
that,  therefore,  we  must  have  as  much  air  as  the  two  currents 
bring  in  at  the  bottom  to  flow  out  at  the  top.  What  flows  out 
at  the  top  is  carried  back  north  and  south  by  these  upper  currents, 
which  are  thus  proved  to  exist  and  to  flow  counter  to  the  trade- 
winds. 

836.  Using  still  farther  this  mode  of  illustration  :  if  we  liken 
the  calm  belt  of  Cancer  and  the  calm  belt  of  Capricorn  each  to  a 
great  atmospherical  trough  extending  around  the  earth  also,  we 

*  Bijdrage  Natuurkundige  Beschrijving  der  zeen,  vertaald  door  M.  H.  Jansen,  Lui- 
tenant  ter  zee. 


290  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

shall  see  that  in  this  case  the  currents  are  running  in  at  the  top 
and  out  at  the  hottom  (§  132). 

837.  The  belt  of  equatorial  calms  is  a  belt  of  constant  precipi- 
tation. Captain  Wilkes,  of  the  Exploring  Expedition,  when  he 
crossed  it  in  1838,  found  it  to  extend  from  4°  north  to  12°  north. 
He  was  ten  days  in  crossing  it,  and  during  those  ten  days  rain  fell 
to  the  depth  of  6.15  inches,  or  at  the  rate  of  eighteen  feet  and  up- 
ward during  the  year.  In  the  summer  months  this  belt  of  calms 
is  found  between  the  parallels  of  8°  and  14°  of  north  latitude,  and 
in  the  spring  between  5°  south  and  4°  north.    (  Vide  Plate  YIII.) 

838.  This  calm  belt,  in  its  motions  from  south  to  north  and 
back,  carries  with  it  the  rainy  seasons  of  the  torrid  zone,  always 
arriving  at  certain  parallels  at  stated  periods  of  the  year ;  conse- 
quently, by  attentively  considering  Plate  VIII.,  one  can  tell  what 
places  within  the  range  of  this  zone  have,  during  the  year,  two 
rainy  seasons,  what  one,  and  what  are  the  rainy  months  for  each 
locality. 

839.  Were  the  northeast  and  the  southeast  trades,  with  the  belt 
of  equatorial  calms,  of  different  colors,  and  visible  to  an  astron- 
omer in  one  of  the  planets,  he  might,  by  the  motion  of  these  belts 
or  girdles  alone,  tell  the  seasons  with  us.  He  would  see  them  at 
one  season  going  north,  then  appearing  stationary,  and  then  com- 
mencing their  return  to  the  south.  But,  though  he  would  observe 
(§  188)  that  they  follow  the  sun  in  his  annual  course,  he  would 
remark  that  they  do  not  change  their  latitude  as  much  as  the  sun 
does  his  declination ;  he  would,  therefore,  discover  that  their  ex- 
tremes of  declination  are  not  so  far  asunder  as  the  tropics  of  Can- 
cer and  Capricorn,  though  in  certain  seasons  the  changes  from  day 
to  day  are  very  great.  He  would  observe  that  these  zones  of 
winds  and  calms  have  their  tropics  or  stationary  nodes,  about 
which  they  linger  near  three  months  at  a  time ;  and  that  they  pass 
from  one  of  their  tropics  to  the  other  in  a  little  less  than  another 
three  months.  Thus  he  would  observe  the  whole  system  of  belts 
to  go  north  from  the  latter  part  of  May  till  some  time  in  August. 
Then  they  would  stop  and  remain  stationary  till  winter,  in  Decem- 
b)er ;  when  again  they  would  commence  to  move  rapidly  over  the 
ocean,  and  down  toward  the  south,  until  the  last  of  February  or 


THE  WINDS.  291 

the  first  of  March  ;  then  again  they  would  become  stationary,  and 
remain  about  this,  tlieir  southern  tropic,  till  May  again. 

840.  The  Hoese  Latitudes. — Having  completed  the  physical 
examination  of  the  equatorial  calms  and  winds,  if  the  supposed  ob- 
server should  now  turn  his  telescope  toward  the  poles  of  our  earth, 
he  would  observe  a  zone  of  calms  bordering  the  northeast  trade- 
winds  on  the  north  (§  131),  and  another  bordering  the  southeast 
trade-winds  on  the  south  (§  137).  These  calm  zones  also  would 
be  observed  to  vibrate  up  and  down  with  the  trade-wind  zones, 
partaking  (§  191)  of  their  motions,  and  following  the  declination 
of  the  sun. 

841.  On  the  polar  side  of  each  of  these  two  calm  zones  there 
would  be  a  broad  band  extending  up  into  the  polar  regions,  the 
prevailing  winds  within  which  are  the  opposites  of  the  trade-winds, 
viz.,  southwest  in  the  northern  and  northwest  in  the  southern 
hemisphere.  The  equatorial  edge  of  these  calm  belts  is  near  the 
tropics,  and  their  average  breadth  is  10°  or  12^.  On  one  side  of 
these  belts  (§  131)  the  winds  blow  perpetually  toward  the  equator ; 
on  the  other,  their  prevailing  direction  is  toward  the  poles.  They 
are  called  (§  131)  the  "horse  latitudes"  by  seamen. 

842.  Along  the  polar  borders  of  these  two  calm  belts  (§  190) 
we  have  another  region  of  precipitation,  though  generally  the  rains 
here  are  not  so  constant  as  they  are  in  the  equatorial  calms.  The 
precipitation  near  the  tropical  calms  is  nevertheless  sufficient  to 
mark  the  seasons  ;  for  whenever  these  calm  zones,  as  they  go  from 
north  to  south  with  the  sun,  leave  a  given  parallel,  the  rainy  sea- 
son of  that  parallel,  if  it  be  in  winter,  is  said  to  commence.  Hence 
we  may  explain  the  rainy  season  in  Chili  at  the  south,  and  in  Cal- 
ifornia at  the  north. 

843.  The  Westeely  Winds. — To  complete  the  physical  ex- 
amination of  the  earth's  atmosphere  which  we  have  supposed  an 
astronomer  in  one  of  the  planets  to  have  undertaken  according  to 
the  facts  developed  by  the  Wi7icl  and  Current  Charts,  it  remains 
for  him  to  turn  his  telescope  upon  the  southwest  passage  winds  of 
the  northern  hemisphere,  pursue  them  into  the  arctic  regions,  and 
see  theoretically  how  they  get  there,  and,  being  there,  what  be- 
comes of  them. 

844.  From  the  parallel  of  40°  up  toward  the  north  pole,  the 

T 


292  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

prevailing  winds,  as  already  remarked,  are  the  soutliwest  passage 
winds  (Plate  VIII.),  or,  as  they  are  more  generally  called  by  mar- 
iners, the  "westerly"  winds;  these,  in  the  Atlantic,  prevail  over 
the  "  easterly"  winds  in  the  ratio  of  about  two  to  one. 

845.  Now  if  w^e  suppose,  and  such  is  probably  the  case,  these 
"  westerly"  winds  to  convey  in  two  days  a  greater  volume  of  at- 
mosphere toward  the  arctic  circle  than  those  "  easterly"  winds  can 
bring  back  in  one,  we  establish  the  necessity  for  an  upper  current 
by  which  this  difference  may  be  returned  to  the  tropical  calms  of 
our  hemisphere.  Therefore  there  must  be  some  place  in  the  polar 
regions  (§  154)  at  which  these  southwest  winds  cease  to  go  north, 
and  from  which  they  commence  their  return  to  the  south,  and  this 
locality  must  be  in  a  region  peculiarly  liable  to  calms.  It  is  an- 
other atmospherical  node  in  which  the  motion  of  the  air  is  upward, 
with  a  decrease  of  barometric  pressure.     It  is  marked  P,  Plate  I. 

846.  To  appreciate  the  force  and  volume  of  these  polar-bound 
winds  in  the  southern  hemisphere,  it  is  necessary  that  one  should 
"run  them  down"  in  that  waste  of  waters  beyond  the  parallel  of 
40°  S.,  where  "the  winds  howl  and  the  seas  roar."  The  billows 
there  lift  themselvfes  up  in  long  ridges  with  deep  hollows  between 
them.  They  run  high  and  fast,  tossing  their  white  caps  aloft  in 
the  air,  looking  like  the  green  hills  of  a  rolling  prairie  capped  with 
snow,  and  chasing  each  other  in  sport.  Still  their  march  is  state- 
ly and  their  roll  majestic.  The  scenery  among  them  is  grand, 
and  the  Australian-bound  trader,  after  doubling  the  Cape  of  Good 
Hope,  finds  herself  followed  for  weeks  at  a  time  by  these  magnif- 
icent rolling  swells,  driven  and  lashed  by  the  "  brave  west  winds" 
furiously.  A  sailor's  bride,  performing  this  voyage  with  her  gallant 
husband,  thus  alludes  in  her  "  abstract  log"  to  these  rolling  seas : 

847.  "We  had  some  magnificent  gales  off  the  Cape,  when  the 
coloring  of  the  waves,  the  transition  from  gray  to  clear  brilliant 
green,  with  the  milky-white  foam,  struck  me  as  most  exquisite. 
And  then  in  rough  weather  the  moral  picture  is  so  fine,  the  calm- 
ness and  activity  required  is  such  an  exhibition  of  the  power  of 
mind  over  the  elements,  that  I  admired  the  sailors  fully  as  much 
as  the  sea,  and,  of  course^  the  sailor  in  command  most  of  all ;  in- 
deed, a  sea  voyage  more  than  fulfills  my  expectations." 


THE  WINDS. 


293 


PLATE  IV. 


sjs      8|n 


6|o      aJD      5|o     4i3      ajo     3i5      3|q      ais      zio      115     ilo 


294        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  XY. 

CLIMATES   OF   THE   OCEAN. 

Milky  Way  of  the  Sea,  ^  848.— Contrasted  with  Climates  Ashore,  852. — Movements 
of  Isotherms,  854. — Mean  Temperature  of  Sea  and  Air,  860. — Rain  in  high  Lati- 
tudes at  Sea,  863. — Climate  of  England  affected  by  Coast  Line  of  Brazil,  871. — 
The  Gulf  of  Guinea,  875. — Summer  in  the  Northern  Hemisphere  hotter  than  in  the 
Southern,  883. — A  Harbor  for  Icebergs,  884. — Course  of  the  Isothermal  Line  across 
the  Atlantic,  887. 

848.  Thermal  charts,  showing  the  temperature  of  the  surface 
of  the  Atlantic  Ocean  by  actual  observations  made  indiscrimin-. 
atelj  all  over  it,  and  at  all  times  of  the  year,  have  been  published 
by  the  National  Observatory.  The  isothermal  lines  which  these 
charts  enable  us  to  draw,  and  some  of  which  are  traced  on  Plate 
IV.,  afford  the  navigator  and  the  philosopher  much  valuable  and 
interesting  information  touching  the  circulation  of  the  oceanic  wa- 
ters, including  the  phenomena  of  the  cold  and  warm  sea  currents ; 
they  also  cast  light  upon  the  climatology  of  the  sea,  its  liyeto- 
graphic  peculiarities,  and  the  climatic  conditions  of  various  regions 
of  the  earth  ;  they  show  that  the  profile  of  the  coast-line  of  inter- 
tropical America  assists  to  give  expression  to  the  mild  climate  of 
Southern  Europe ;  they  also  increase  our  knowledge  concerning  the 
Gulf  Stream,  for  it  enables  us  to  mark  out,  for  the  mariner's  guid- 
ance, that  "  Milky  Way"  in  the  ocean,  the  waters  of  which  teem, 
and  sparkle,  and  glow  with  life  and  incipient  organisms  as  they  run 
across  the  Atlantic.  In  them  are  found  the  clusters  and  nebula3 
of  the  sea  which  stud  and  deck  the  great  highway  of  ships  on  their 
voyage  between  the  Old  World  and  the  New ;  and  these  lines  as- 
sist to  point  out  for  the  navigator  their  limits  and  his  way.  They 
show  this  via  lactea  to  have  a  vibratory  motion  in  the  sea  that  calls 
to  mind  the  graceful  wavings  of  a  pennon  as  it  floats  gently  to  the 
breeze.  Indeed,  if  we  imagine  the  head  of  the  Gulf  Stream  to  be 
hemmed  in  by  the  land  in  the  Straits  of  Bemini,  and  to  be  sta- 


CLIMATES  OF  THE  OCEAN.  295 

tionar  J  there,  and  then  liken  the  tail  of  the  Stream  itself  to  an  im- 
mense  pennon  floating  gently  in  the  current,  such  a  motion  as  such 
a  streamer  may  be  imagined  to  have — very  much  such  a  motion — 
do  my  researches  show  the  tail  of  the  Gulf  Stream  to  have.  Run- 
ning between  banks  of  cold  water  (§  1),  it  is  pressed  now  from  the 
north,  now  from  the  south,  according  as  the  great  masses  of  sea 
water  on  either  hand  may  change  or  fluctuate  in  temperature. 

849.  In  September,  when  the  waters  in  the  cold  regions  of  the 
north  have  been  tempered,  and  made  warm  and  light  by  the  heat 
of  summer,  its  limits  on  the  left  (Plate  YI.)  are  as  denoted  by  the 
line  of  arrows ;  but  after  this  great  sun-swing,  the  waters  on  the 
left  side  begin  to  lose  their  heeit,  grow  cold,  become  heavy,  and 
press  the  hot  waters  of  this  stream  into  the  channel  marked  out 
for  them. 

850.  Thus  it  acts  like  a  pendulum,  slowly  propelled  by  heat  on 
one  side  and  repelled  by  cold  on  the  other.  In  this  view,  it  be- 
comes a  chronograph  for  the  sea,  keeping  time  for  its  inhabitants, 
and  marking  the  seasons  for  the  great  whales ;  and  there  it  has 
been  foi^  all  time  vibrating  to  and  fro,  once  every  year,  swinging 
from  north  to  south,  and  from  south  to  north  again,  a  great  self- 
regulating,  self-com]3ensating  pendulum. 

851.  In  seeking  information  concerning  the  climates  of  the 
ocean,  it  is  well  not  to  forget  this  remarkable  contrast  between  its 
climatology  and  that  of  the  land,  namely :  on  the  land,  February 
and  August  are  considered  the  coldest  and  the  hottest  months ; 
but  to  the  inhabitants  of  the  sea,  the  annual  extremes  of  cold  and 
heat  occur  in  the  months  of  March  and  September.  On  the  dry 
land,  after  the  winter  "  is  past  and  gone,"  the  solid  parts  of  the 
earth  continue  to  receive  from  the  sun  more  heat  in  the  day  than 
they  radiate  at  night,  consequently  there  is  an  accumulation  of 
caloric,  which  continues  to  increase  until  August.  The  summer 
is  now  at  its  height ;  for,  with  the  close  of  this  month,  the  solid 
parts  of  the  earth's  crust  and  the  atmosphere  above  begin  to  dis- 
pense with  their  heat  faster  than  the  rays  of  the  sun  can  impart 
fresh  supplies,  and,  consequently,  the  climates  which  they  regu- 
late grow  cooler  and  cooler  until  the  dead  of  winter  again. 

852.  But  at  sea  a  different  rule  seems  to  prevail.     Its  waters 


296  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

are  the  store-houses  in  which  the  surplus  heat  of  summer  is  stored 
away  against  the  severity  of  winter,  and  its  waters  continue  to 
grow  warmer  for  a  month  after  the  weather  on  shore  has  begun 
to  o-et  cool.  Tliis  brings  the  highest  temperature  to  the  sea  in 
September,  the  lowest  in  March.  Plate  IV.  is  intended  to  show 
the  extremes  of  heat  and  cold  to  which  the  waters — not  the  ice — ■ 
of  the  sea  are  annually  subjected,  and  therefore  the  isotherms  of 
40°,  50°,  60°,  70°,  and  80°  have  been  drawn  for  March  and  Sep- 
tember, the  months  of  extreme  heat  and  extreme  cold  to  the  in- 
habitants of  the  "  great  deep."  Corresponding  isotherms  for  any 
other  month  will  fall  between  these,  taken  by  pairs.  Thus  the 
isotherm  of  70°  for  July  will  fall  nearly  midway  between  the  same 
isotherms  (70°)  for  March  and  September. 

853.  A  careful  study  of  this  plate,  and  the  contemplation  of  the 
benign  influences  of  the  sea  upon  the  climates  which  we  enjoy, 
suggest  many  beautiful  thoughts ;  for  by  such  study  we  get  a 
p'limpse  into  the  arrangements  and  the  details  of  that  exquisite 
machinery  in  the  ocean  which  enables  it  to  perform  all  its  offices, 
and  to  answer  with  fidelity  its  marvelous  adaptatiolis. 

854.  How,  let  us  inquire,  does  the  isotherm  of  80°,  for  instance, 
get  from  its  position  in  March 'to  its  position  in  September?  Is 
it  wafted  along  by  currents,  that  is,  by  water  which,  after  having 
been  heated  near  the  equator  to  80°,  then  flows  to  the  north  with- 
this  temperature?  Or  is  it  carried  there  simply  by  the  rays  of 
the  sun,  as  the  snow-line  is  carried  up  the  mountain  in  summer  ? 
We  have  reason  to  believe  that  it  is  carried  from  one  parallel  to 
another  by  each  of  these  agents  acting  together,  but  mostly  through 
the  instrumentality  of  currents,  for  currents  are  the  chief  agents 
for  distributing  heat  to  the  various  parts  of  the  ocean.  The  sun 
with  his  rays  would,  were  it  not  for  currents,  raise  the  water  in  the 
torrid  zone  to  blood  heat ;  but  before  that  can  be  done,  they  run 
off"  with  it  toward  the  poles,  softening,  and  mitigating,  and  temper- 
ing climates  by  the  way.  The  provision  for  this  is  as  beautiful 
as  it  is  benign  ;  for,  to  answer  a  physical  adaptation,  it  is  provided 
by  a  law  of  nature  that  when  the  temperature  of  water  is  raised, 
it  shall  expand  ;  as  it  expands,  it  must  become  lighter,  and  just  in 
proportion,  as  its  specific  gravity  is  altered,  just  in  that  proportion 


CLIMATES  OF  THE  OCEAN.  297 

is  equilibrium  in  the  sea  destroyed.  Arrived  at  this  condition,  it 
is  ordained  that  this  hot  water  shall  obey  another  law  of  nature, 
which  requires  it  to  run  away,  and  hasten  to  restore  that  equilib- 
rium. Were  these  isothermal  lines  moved  only  by  the  rays  of  the 
sun,  they  would  slide  up  and  down  the  ocean  like  so  many  paral- 
lels of  latitude — at  least  there  would  be  no  breaks  in  them,  like  that 
which  we  see  in  the  isotherm  of  80°  for  September.  It  appears 
from  this  line  that  there  is  a  part  of  the  ocean  near  the  equator, 
and  about  midway  the  Atlantic,  which,  with  its  waters,  never  does 
attain  the  temperature  of  80°  in  September.  Moreover,  this  iso- 
therm of  80°  will  pass,  in  the  North  Atlantic,  from  its  extreme 
southern  to  its  extreme  northern  declination — nearly  two  thou- 
sand miles — in  about  three  months.  Thus  it  travels  at  the  rate 
of  about  twenty-two  miles  a  day.  Surely,  without  the  aid  of  cur- 
rents, the  rays  of  the  sun  could  not  drive  it  along  that  fast. 

855.  Being  now  left  to  the  gradual  process  of  cooling  by  evap- 
oration, atmospherical  contact,  and  radiation,  it  occupies  the  other 
eight  or  nine  months  of  the  year  in  slowly  returning  south  to  the 
parallel  whence  it  commenced  to  flow  northward.  As  it  does  not 
cool  as  rapidly  as  it  was  heated,  the  disturbance  of  equilibrium  by 
alteration  of  specific  gravity  is  not  so  sudden,  nor  the  current  which 
is  required  to  restore  it  so  rapid.  Hence  the  slow  rate  of  move- 
ment at  which  this  line  travels  on  its  march  south. 

856.  Between  the  meridians  of  25°  and  30°  west,  the  isotherm 
of  60°  in  September  ascends  as  high  as  the  parallel  of  56°.  In 
October  it  reaches  the  parallel  of  50°  north.  In  November  it  is 
found  between  the  parallels  of  45°  and  47°,  and  by  December  it 
has  nearly  reached  its  extreme  southern  descent  between  these 
meridians,  which  it  accomplishes  in  January,  standing  then  near 
the  parallel  of  40°.  It  is  all  the  rest  of  the  year  in  returning 
northward  to  the  parallel  whence  it  commenced  its  flow  to  the 
south  in  September. 

857.  Now  it  will  be  observed  that  this  is  the  season — from 
September  to  December — -immediately  succeeding  that  in  which 
the  heat  of  the  sun  has  been  playing  with  greatest  activity  upon 
the  polar  ice.  Its  melted  waters,  which  are  thus  put  in  motion  in 
June,  July,  and  August,  would  probably  occupy  the  fall  months  in 


298  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

reaching  the  parallels  indicated.  These  waters,  though  cold,  and 
rising  gradually  in  temperature  as  they  flow  south,  are  probably 
fresher,  and  if  so,  probably  lighter  than  the  sea-water ;  and  there- 
fore it  may  well  be  that  both  the  warmer  and  cooler  systems  of 
these  isothermal  lines  are  made  to  vibrate  up  and  down  the  ocean 
principally  by  a  gentle  surface  current  in  the  season  of  quick  mo- 
tion, and  in  the  season  of  the  slow  motion  principally  by  a  grad- 
ual process  of  calorific  absorption  on  the  one  hand,  and  by  a  grad- 
ual process  of  cooling  on  the  other. 

858.  We  have  precisely  such  phenomena  exhibited  by  the  wa- 
ters of  the  Chesapeake  Bay  as  they  spread  themselves  over  the 
sea  in  winter.  At  this  season  of  the  year,  the  charts  show  that 
water  of  very  low  temperature  is  found  projecting  out  and  over-: 
lapping  the  usual  limits  of  the  Gulf  Stream.  The  outer  edge  of 
this  cold  water,  though  jagged,  is  circular  in  its  shape,  having  its 
centre  near  the  mouth  of  the  Bay.  The  waters  of  the  Bay,  being 
fresher  than  those  of  the  sea,  may,  therefore,  though  colder,  be 
lis-liter  than  the  warmer  waters  of  the  ocean.  And  thus  we  have 
repeated  here,  though  on  a  smaller  scale,  the  phenomenon  as  to  the 
flow  of  cold  waters  from  the  north,  which  force  the  surface  iso- 
therm of  60°  from  latitude'56o  to  40°  during  three  or  four  months. 

859.  Changes  in  the  color  or  depth  of  the  water,  and  the  shape 
of  the  bottom,  etc.,  would  also  cause  changes  in  the  temperature 
of  certain  parts  of  the  ocean,  by  increasing  or  diminishing  the  ca- 
pacities of  such  parts  to  absorb  or  radiate  heat ;  and  this,  to  some 
extent,  would  cause  a  bending,  or  produce  irregular  curves  in  the 
isothermal  lines. 

860.  After  a  careful  study  of  this  plate,  and  the  Thermal  Charts 
of  the  Atlantic  Ocean,  from  which  the  materials  for  the  former  were 
derived,!  am  led  to  infer  that  the  mean  temperature  of  the  atmos- 
phere between  the  parallels  of  56°  and  40°  north,'  for  instance,  and 
over  that  part  of  the  ocean  in  which  we  have  been  considering  the 
fluctuations  of  the  isothermal  line  of  60°,  is  at  least  60°  of  Fah- 
renheit, and  upward,  from  January  to  August,  and  that  the  heat 
which  the  waters  of  the  ocean  derive  from  this  source — atmos- 
pherical contact  and  radiation — is  one  of  the  causes  which  move 
the  isotherm  of  60^^  from  its  January  to  its  September  parallel. 


CLIMATES  OF  THE  OCEAN.  299 

861.  It  is  well  to  consider  another  of  the  causes  wliicli  are  at 
work  upon  the  currents  in  this  part  of  the  ocean,  and  which  tend 
to  give  the  rapid  southwardly  motion  to  the  isotherm  of  60°.  We 
know  the  mean  dew-point  must  always  be  below  the  mean  tem- 
perature of  any  given  place,  and  that,  consequently,  as  a  general 
rule,  at  sea  the  mean  dew-point  due  the  isotherm  of  60°  is  higher 
than  the  mean  dew-point  along  the  isotherm  of  50°,and  this,  again, 
higher  than  that  of  40° — this  than  30°,  and  so  on.  Now  suppose, 
merely  for  the  sake  of  illustration,  that  the  mean  dew-point  for 
each  isotherm  be  5°  lower  than  the  mean  temperature,  wo  should 
then  have  the  atmosphere  which  crosses  the  isotherm  of  60°,  with 
a  mean  dew-point  of  55°,  gradually  precipitating  its  vapors  until 
it  reaches  the  isotherm  of  50°,  with  a  mean  dew-point  of  45° ;  by 
which  difference  of  dew-point  the  total  amount  of  precipitation 
over  the  entire  zone  between  the  isotherms  of  60°  and  50°  has 
exceeded  the  total  amount  of  evaporation  from  the  same  surface. 
The  prevailing  direction  of  the  winds  to  the  north  of  the  fortieth 
parallel  of  north  latitude  is  from  the  southward  and  westward 
(Plate  VIII.) ;  in  other  words,  it  is  from  the  higher  to  the  lower 
isotherms.  Passing,  therefore,  from  a  higher  to  a  lower  tempera- 
ture over  the  ocean,  the  total  amount  of  vapor  deposited  by  any- 
given  volume  of  atmosphere,  as  it  is  blown  from  the  vicinity  of 
the  tropical  toward  that  of  the  polar  regions,  is  greater  than  that 
which  is  taken  up  again. 

862.  The  area  comprehended  on  Plate  VIII.  between  the  iso- 
therms of  40°  and  50°  Fahrenheit  is  less  than  the  area  compre- 
hended between  the  isotherms  50°  and  60°,  and  this,  again,  less 
than  the  area  between  this  last  and  70°,  for  the  same  reason  that 
the  area  between  the  parallels  of  latitude  50°  and  60°  is  less  than 
the  area  between  the  parallels  of  latitude  40°  and  50°  ;  therefore, 
more  rain  to  the  square  inch  ought  to  fall  upon  the  ocean  between 
the  colder  isotherms  of  10°  difference,  than  between  the  warmer 
isotherms  of  the  same  difference.  This  is  an  interesting  and  an 
important  view,  therefore  let  me  make  myself  clear :  the  aqueous 
isotherm  of  50°,  in  its  extreme  northern  reach,  touches  the  paral- 
lel of  60°  north.  Now  between  this  and  the  equator  there  are 
but  three  isotherms,  60°,  70°,  and  80°,  with  the  common  differ- 


300       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

ence  of  10°.  But  between  the  isotherm  of  40°  and  the  pole  there 
are  at  least  five  others,  viz.,  40°,  30°,  20°,  10°,  0°,  with  a  com- 
mon difference  of  10°.  Thus,  to  the  north  of  the  isotherm  50°, 
the  vapor  which  would  saturate  the  atmosphere  from  zero,  and 
perhaps  far  below,  to  near  40°,  is  deposited,  while  to  the  south  of 
50°  the  vapor  which  would  saturate  it  from  the  temperature  of 
50P  up  to  that  of  80°  can  only  be  deposited.  At  least,  such  would 
be  the  case  if  there  were  no  irregularities  of  heated  plains,  mount- 
ain'ranges,  land,  etc.,  to  disturb  the  laws  of  atmospherical  circu- 
lation as  they  apply  to  the  ocean. 

863.  Having  therefore,  theoretically,  at  sea  more  rain  in  high 
latitudes,  we  should  have  more  clouds  ;  and  therefore  it  would  re- 
quire a  longer  time  for  the  sun,  with  his  feeble  rays,  to  raise  the 
temperature  of  the  cold  water,  which,  from  September  to  January, 
has  brou2:ht  the  isotherm  of  60°  from  latitude  56^^  to  40°,  than  it 
did  for  these  cool  surface  currents  to  float  it  down.  After  this 
southward  motion  of  the  isotherm  of  60°  has  been  checked  in  De- 
cember by  the  cold,  and  after  the  sources  of  the  current  which 
brought  it  down  have  been  bound  in  fetters  of  ice,  it  pauses  in  the 
long  nights  of  the  northern  winter,  and  scarcely  commences  its  re- 
turn till  the  sun  recrosses  the  equator,  and  increases  its  power  as 
well  in  intensity  as  in  duration. 

864.  Thus,  in  studying  the  physical  geography  of  the  sea,  we 
have  the  effects  of  night  and  day,  of  clouds  and  sunshine,  upon  its 
currents  and  its  climates,  beautifully  developed.  These  effects  are 
modified  by  the  operations  of  certain  powerful  agents  which  re- 
side upon  the  land ;  nevertheless,  feeble  though  those  of  the  for- 
mer class  may  be,  a  close  study  of  this  plate  will  indicate  that  they 
surely  exist. 

865.  Now,  returning  toward  the  south :  we  may,  on  the  other 
hand,  infer  that  the  mean  atmospherical  temperatiu'e  for  the  par- 
allels between  which  the  isotherm  of  80°  fluctuates  is  below  80°, 
at  least  for  the  nine  months  of  its  slow  motion.  This  vibratory 
motion  suggests  the  idea  that  there  is,  probably,  somewhere  be- 
tween the  isotherm  of  80°  in  August  and  the  isotherm  of  60°  in 
January,  a  line  or  belt  of  invariable  or  nearly  invariable  temper- 
ature, which  extends  on  the  surface  of  the  ocean  from  one  side  of 


CLIMATES  OF  THE  OCEAN.  301 

the  Atlantic  to  the  other.     This  line  or  band  may  have  its  cycles 
also,  but  they  are  probably  of  long  and  uncertain  periods. 

866.  The  fact  has  been  pretty  clearly  established  by  the  dis- 
coveries to  which  the  wind  and  current  charts  have  led,  that  the 
western  half  of  the  Atlantic  Ocean  is  heated  up,  not  by  the  Gulf 
Stream  alone,  as  is  generally  supposed,  but  by  the  great  equato- 
rial caldron  to  the  west  of  longitude  35°,  and  to  the  north  of  Cape 
St.  Koque,  in  Brazil.  The  lowest  reach  of  the  80°  isotherm  for 
September — if  we  except  the  remarkable  equatorial  flexure  (Plate 
IV.)  which  actually  extends  from  40°  north  to  the  line — to  the 
west  of  the  meridian  of  Cape  St.  Roque,  is  above  its  highest  reach 
to  the  east  of  that  meridian.  And  now  that  we  have  the  fact,  how 
obvious,  beautiful,  and  striking  is  the  cause ! 

867.  Cape  St.  Koque  is  in  5°  30^  south.  Now  study  the  con- 
figuration of  the  Southern  American  Continent  from  this  cape  to 
the  Windward  Islands  of  the  West  Indies,  and  take  into  account 
also  certain  physical  conditions  of  these  regions :  the  Amazon,  al- 
ways at  a  high  temperature  because  it  runs  from  west  to  east,  is 
pouring  an  immense  volume  of  warm  water  into  this  part  of  the 
ocean.  As  this  water  and  the  heat  of  the  sun  raise  the  temperature 
of  the  ocean  along  the  equatorial  sea-front  of  this  coast,  there  is  no 
escape  for  the  liquid  element,  as  it  grows  warmer  and  lighter,  ex- 
cept to  the  north.  The  land  on  the  south  prevents  the  tepid  wa- 
ters from  spreading  out  in  that  direction  as  they  do  to  the  east  of 
35°  west,  for  here  there  is  a  space,  about  18  degrees  of  longitude 
broad,  in  which  the  sea  is  clear  both  to  the  north  and  south. 

868.  They  must  consequently  flow  north.  A  mere  inspection 
of  the  plate  is  suihcient  to  make  obvious  the  fact  that  the  warm 
waters  which  are  found  east  of  the  usual  limits  assigned  the  Gulf 
Stream,  and  between  the  parallels  of  30°  and  40°  north,  do  not 
come  from  the  Gulf  Stream,  but  from  this  great  equatorial  cal- 
dron, which  Cape  St.  Eoque  blocks  up  on  the  south,  and  which 
forces  its  overheated  waters  up  to  the  fortieth  degree  of  north  lat-  . 
itude,  not  through  the  Caribbean  Sea  and  Gulf  Stream,  but  over 
the  broad  surface  of  the  left  bosom  of  the  Atlantic  Ocean. 

869.  Here  we  are  again  tempted  to  pause  and  admire  the  beau- 
tiful revelations  which,  in  the  benign  system  of  terrestrial  adapta- 


302  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

tion,  these  researches  into  the  physics  of  the  sea  unfold  and  spread 
out  before  us  for  contemplation.  In  doing  this,  we  shall  have  a 
free  pardon  from  those  at  least  who  delight  "to  look  through  na- 
ture up  to  nature's  God." 

870.  What  two  things  in  nature  can  be  apparently  more  remote 
in  their  physical  relations  to  each  other,  than  the  climate  of  West- 
ern Europe  and  the  profile  of  a  coast-line  in  South  America  ?  Yet 
this  plate  reveals  to  us  not  only  the  fact  that  these  relations  be- 
tween the  two  are  the  most  intimate,  but  makes  us  acquainted 
with  the  arrangements  by  which  such  relations  are  established. 

871.  The  barrier  which  the  South  American  shore-line  opposes 
to  the  escape,  on  the  south,  of  the  hot  waters  from  this  great  equa- 
torial caldron  of  St.  Eoque,  causes  them  to  flow  north,  and  in  Sep- 
tember, as  the  winter  approaches,  to  heat  up  the  western  half  of 
the  Atlantic  Ocean,  and  to  cover  it  with  a  mantle  of  w^armth  above 
summer  heat  as  far  up  as  the  parallel  of  40°.  Here  heat  to  tem- 
per the  winter  climate  of  Western  Europe  is  stored  away  as  in  an 
air-chamber  to  furnace-heated  apartments  ;  and  during  the  winter, 
when  the  fire  of  the  solar  rays  sinks  down,  the  westwardly  winds 
and  eastwardly  currents  are  sent  to  perform  their  office  in  this  be- 
nign arrangement.  Though  unstable  and  capricious  to  us  they 
seem  to  be,  they  nevertheless  "fulfill  His  commandments"  with 
regularity  and  perform  their  offices  with  certainty.  In  tempering 
the  climates  of  Europe  with  heat  in  winter  that  has  been  bottled 
away  in  the  waters  of  the  ocean  during  summer,  these  winds  and 
currents  are  to  be  regarded  as  the  flues  and  regulators  for  distrib- 
uting it  at  the  right  time,  and  at  the  right  places,  in  the  right 
quantities. 

872.  By  March,  when  "  the  winter  is  past  and  gone,"  the  fur- 
nace which  had  been  started  by  the  rays  of  the  sun  in  the  pre- 
vious summer,  and  which,  by  autumn,  had  heated  up  the  ocean 
in  our  hemisphere,  has  cooled  down.  The  caldron  of  St.  Eoque, 
ceasing  in  activity,  has  failed  in  its  supplies,  and  the  chambers  of 
warmth  upon  the  northern  sea,  having  been  exhausted  of  their 
heated  water,  which  has  been  expended  in  the  manner  already  ex- 
plained, have  contracted  their  limits.  The  surface  of  heated  wa- 
ter which,  in  September,  was  spread  out  over  the  western  half  of 


CLIMATES  OF  THE  OCEAN.  303 

the  Atlantic,  from  the  equator  to  the  parallel  of  40^  north,  and 
■which  raised  this  immense  area  to  the  temperature  of  80°  and  up- 
ward, is  not  to  be  found  in  early  spring  on  this  side  of  the  parallel 
of  8°  north. 

873.  The  isotherm  of  80°  in  ^larch,  after  quitting  the  Caribbean 
Sea,  runs  parallel  with  the  South  American  coast  toward  Cape 
St.  Roque,  keeping  some  8  or  10  degrees  from  it.  Therefore  the 
heat  dispensed  over  Europe  from  this  caldron  falls  off  in  March. 
But  at  this  season  the  sun  comes  forth  with  fresh  supplies ;  he 
then  crosses  the  line  and  passes  over  into  the  northern  hemisphere ; 
observations  show  that  the  process  of  heating  the  water  in  this 
great  caldron  for  the  next  winter  is  now  about  to  commence. 

874.  In  the  mean  time,  so  benign  is  the  system  of  cosmical  ar- 
rangements, another  process  of  raising  the  temperature  of  Europe 
commences.  The  land  is  more  readily  impressed  than  the  sea  by 
the  heat  of  the  solar  rays ;  at  this  season,  then,  the  summer  cli- 
mate due  these  transatlantic  latitudes  is  modified  by  the  action  of 
the  sun's  rays  directly  upon  the  land.  The  land  receives  heat  from 
them,  but,  instead  of  having  the  capacity  of  water  for  retaining  it, 
it  imparts  it  straightway  to  the  air ;  and  thus  the  proper  climate, 
because  it  is  the  climate  which  the  Creator  has,  for  his  own  wise' 
purposes,  allotted  to  this  portion  of  the  eartb,  is  maintained  until 
the  marine  caldron  of  Cape  St.  Roque  and  the  tropics  is  again  heat- 
ed and  brought  into  the  state  for  supplying  the  means  of  maintain- 
ing the  needful  temperature  in  Europe  during  the  absence  of  the 
sun  in  the  other  hemisphere. 

875.  In  like  manner,  the  Gulf  of  Guinea  forms  a  caldron  and  a 
furnace,  and  spreads  out  over  the  South  Atlantic  an  air-chamber 
for  heating  up  in  winter  and  keeping  warm  the  extra-tropical  re- 
gions of  South  America.  Every  traveler  has  remarked  upon  tlie 
mild  climate  of  Patagonia  and  the  Falkland  Islands. 

876.  "  Temperature  in  high  southern  latitudes,"  says  a  very 
close  observer,  who  is  co-operating  with  me  in  collecting  materials, 
"  differs  greatly  from  the  temiperature  in  northern.  In  southern 
latitudes  there  seem  to  be  no  extremes  of  heat  and  cold,  as  at  the 
north.  N"ewport,  Ehode  Island,  for  instance,  latitude^  41°  north, 
longitude  71°  west,  and  Rio  Negro,  latitude  41°  south,  and  Ion- 


304       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

gitude  63°  west,  as  a  comparison :  in  the  former,  cattle  liave  to  be 
stabled  and  fed  during  the  winter,  not  being  able  to  get  a  living 
in  the  fields  on  account  of  snow  and  ice.  In  the  latter,  the  cattle 
feed  in  the  fields  all  winter,  there  being  plenty  of •  vegetation  and 
no  use  of  hay.  On  the  Falkland  Islands  (latitude  51-2°  south), 
thousands  of  bullocks,  sheep,  and  horses  are  running  wild  over 
the  country,  gathering  a  living  all  tlixough  the  winter." 

877.  The  water  in  the  equatorial  caldron  of  Guinea  can  not  es- 
cape north — the  shore-liuQ  will  not  permit  it.  It  must,  therefore, 
overflow  to  the  south,  as  that  of  St.  Boque  does  to  the  north,  car- 
rying to  Patagonia  and  the  Falkland  Islands,  beyond  50°  south, 
the  winter  climate  of  Charleston,  South  Carolina,  on  our  side  of 
the  North  Atlantic,  or  of  the  "Emerald  Island"  on  the  other. 

878.  All  geographers  have  noticed,  and  philosophers  have  fre- 
quently remarked  upon  the  conformity,  as  to  the  shore-line  pro- 
file, of  equatorial  America  and  equatorial  Africa. 

879.  It  is  true,  we  can  not  now  tell  the  reason,  though  explana- 
tions founded  upon  mere  conjecture  have  been  offered,  why  there 
should  be  this  sort  of  jutting  in  and  jutting  out  of  the  shore-line, 
as  at  Cape  St.  Roque  and  the  Gulf  of  Guinea,  on  opposite  sides  of 
the  Atlantic ;  but  one  of  the  purposes,  at  least,  which  this  pecul- 
iar configuration  was  intended  to  subserve,  is  without  doubt  now 
revealed  to  us. 

880.  We  see  that,  by  this  configuration,  two  cisterns  of  hot 
water  are  formed  in  this  ocean ;  one  of  which  distributes  heat  and 
warmth  to  western  Europe ;  the  other,  at  the  opposite  season, 
tempers  the  climate  of  eastern  Patagonia. 

881.  Phlegmatic  must  be  the  mind  that  is  not  impressed  with 
ideas  of  grandeur  and  simplicity  as  it  contemplates  that  exquisite 
design,  those  benign  and  beautiful  arrangements,  by  which  the  cli- 
mate of  one  hemisphere  is  made  to  depend  upon  the  curve  of  that 
line  against  which  the  sea  is  made  to  dash  its  waves  in  the  other. 
Impressed  with  the  perfection  of  terrestrial  adaptations,  he  who 
studies  the  economy  of  the  great  cosmical  arrangements  is  re- 
minded that  not  only  is  there  design  in  giving  shore-lines  their 
profile,  the  land  and  the  water  their  proportions,  and  in  placing 
the  desert  and  the  pool  where  they  are,  but  the  conviction  is  forced 


CLIMATES  OF  THE  OCEAN.  3O5 

upon  liim  also,  that  every  hill  and  valley,  with  the  grass  upon  its 
sides,  have  each  its  offices  to  perform  in  the  grand  design. 

882.  March  is,  in  the  southern  hemisphere,  the  first  month  of 
autumn,  as  September  is  with  us ;  consequently,  we  should  ex- 
pect to  find  in  the  South  Atlantic  as  large  an  area  of  water  of  80° 
and  upward  in  ]\Iarch,  as  we  should  find  in  the  North  Atlantic  for 
September.  But  do  we  ?  By  no  means.  The  area  on  this  side 
of  the  equator  is  nearly  double  that  on  the  other. 

883.  Thus  we  have  the  sea  as  a  witness  to  the  fact  that  the 
winds  (§  327)  had  proclaimed,  viz.,  that  summer  in  the  northern 
hemisphere  is  hotter  than  summer  in  the  southern,  for  the  rays  of 
the  sun  raise  on  this  side  of  the  equator  double  the  quantity  of  sea- 
surface  to  a  given  temperature  that  they  do  on  the  other  side ;  at 
least  this  is  the-  case  in  the  Atlantic.  Perhaps  the  breadth  of  the 
Pacific  Ocean,  the  absence  of  large  islands  in  the  temperate  re- 
gions north,  the  presence  of  New  Holland  with  Polynesia  in  the 
South  Pacific,  may  make  a  difference  there.  But  of  this  I  can 
not  now  speak,  for  thermal  charts  of  that  ocean  have  not  yet  been 
prepared. 

884.  Pursuing  the  study  of  the  climates  of  the  sea,  let  us  now 
turn  to  Plate  VI.  Here  we  see  at  a  glance  how  the  cold  waters, 
as  they  come  down  from  the  Arctic  Ocean  through  Davis's  Straits, 
press  upon  the  warm  waters  of  the  Gulf  Stream,  and  curve  their 
channel  into  a  horse-shoe.  Navigators  have  often  been  struck 
with  the  great  and  sudden  changes  in  the  temperature  of  the  wa- 
ter hereabouts.  In  the  course  of  a  single  day's  sail  in  this  part 
of  the  ocean,  changes  of  15°,  or  20°,  and  even  of  30°,  have  been 
observed  to  take  place  in  the  temperature  of  the  sea.  Tlie  cause 
has  puzzled  navigators  long,  but  how  obvious  is  it  now  made  to 
appear !  This  "  bend"  is  the  great  receptacle  of  the  icebergs  which 
drift  down  from  the  north ;  covering  frequently  an  area  of  hund- 
reds of  miles  in  extent,  its  waters  differ  as  much  as  20°,  25°,  and 
in  rare  cases  even  as  much  as  30°  of  temperature  from  those  about 
it.  Its  shape  and  place  are  variable.  Sometimes  it  is  like  a  pen- 
insula, or  tongue  of  cold  water  projected  far  down  into  the  waters 
of  the  Gulf  Stream.  Sometimes  the  meridian  upon  which  it  is 
inserted  into  these  is  to  the  east  of  40°,  sometimes  to  the  west 


306  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

of  50°  longitude.  By  its  discovery  we  have  clearly  unmasked 
the  very  seat  of  that  agent  which  produces  the  Newfoundland  fogs. 
It  is  spread  out  over  an  area  frequently  embracing  several  thou- 
sand square  miles  in  extent,  covered  with  cold  water,  and  sur- 
rounded on  three  sides,  at  least,  with  an  immense  body  of  warm. 
May  it  not  be  that  the  proximity  to  each  other  of  these  two  very 
unequally  heated  surfaces  out  upon  the  ocean  would  be  attended 
by  atmospherical  phenomena  not  unlike  those  of  the  land  and  sea 
breezes  ?  These  warm  currents  of  the  sea  are  powerful  meteoro- 
logical agents.  I  have  been  enabled  to  trace,  in  thunder  and  light- 
ning, the  influence  of  the  Gulf  Stream  in  the  eastern  half  of  the 
Atlantic,  as  far  north  as  the  parallel  of  55°  north ;  for  there,  in 
the  dead  of  winter,  a  thunder-storm  is  not  unusual. 

885.  These  isothermal  lines  of  50°,  60°,  70°,  80°,  etc.,  may 
illustrate  for  us  the  manner  in  which  the  climates  in  the  ocean  are 
regulated.  Like  the  sun  in  the  ecliptic,  they  travel  up  and  down 
the  sea  in  declination,  and  serve  the  monsters  of  the  deep  for  signs 
and  for  seasons. 

886.  It  should  be  borne  in  mind  that  the  lines  of  separation,  as 
drawn  on  Plate  IX.,  between  the  cool  and  warm  waters,  or,  more 
properly  speaking,  between  the  channels  representing  the  great 
polar  and  equatorial  flux  and  reflux,  are  not  so  sharp  in  nature  as 
this  plate  would  represent  them.  In  the  first  place,  the  plate  rep- 
resents the  mean  or  average  limits  of  these  constant  flows — polar 
and  equatorial ;  whereas,  with  almost  every  wind  that  blows,  and 
at  every  change  of  season,  the  line  of  meeting  between  their  wa- 
ters is  shifted.  In  the  next  place,  this  line  of  meeting  is  drawn 
with  a  free  hand  on  the  plate,  as  if  to  represent  an  average  ; 
whereas  there  is  reason  to  believe  that  this  line  in  nature  is  vari- 
able and  unstable  as  to  position,  and  as  to  shape  rough  and  jag- 
ged, and  oftentimes  deeply  articulated.  In  the  sea,  the  line  of 
meeting  between  waters  of  different  temperatures  and  density  is 
not  unlike  the  sutures  of  the  skull-bone  on  a  grand  scale — very 
rough  and  jagged ;  but  on  the  plate  it  is  a  line  drawn  with  a  free 
hand,  for  the  purpose  of  showing  the  general  direction  and  po- 
sition of  the  channels  in  the  sea,  through  which  its  great  polar  and 
equatorial  circulation  is  carried  on. 


CLIMATES  OF  THE  OCEAN.  307 

887.  Now,  continuing  for  a  moment  our  examination  of  Plate 
lY.,  we  are  struck  with  the  fact  that  most  of  the  thermal  lines  there 
drawn  run  from  the  western  side  of  the  Atlantic  toward  the  east- 
ern, in  a  northeastwardly  direction,  and  that,  as  they  approach  the 
shores  of  this  ocean  on  the  east,  they  again  turn  down  for  lower 
latitudes  and  warmer  climates.  This  feature  in  them  indicates, 
more  surely  than  any  direct  observations  upon  the  currents  can 
do,  the  presence,  along  the  African  shores  in  the  North  Atlantic, 
of  a  large  volume  of  cooler  waters.  These  are  the  waters  which, 
having  been  first  heated  up  in  the  caldron  (§866)  of  St.  Roque,  in 
the  Caribbean  Sea,  and  Gulf  of  Mexico,  have  been  made  to  run 
to  the  north,  charged  with  heat  and  electricity  to  temper  and  reg- 
ulate climates  there.  Having  performed  their  offices,  they  have 
cooled  down ;  but,  obedient  still  to  the  "  Mighty  Voice"  which  the 
winds  and  the  waves  obey,  they  now  return  by  this  channel  along 
the  African  shore  to  be  again  replenished  with  warmth,  and  to 
keep  up  the  system  of  beneficent  and  wholesome  circulation  de- 
signed for  the  ocean. 

U 


308  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  XVI. 


THE  DEIFT  OF  THE   SEA. 


Data  used  for  Plate  IX.,  ^  893.— The  Antarctic  Flow,  896.— A  large  Flow  from  the 
Indian  Ocean,  902. — Patches  of  colored  Water,  905. — The  Lagullas  Current,  909. 
— An  immense  Current,  911. — Tide  Rips,  914. — Pulse  of  the  Sea,  920. — Diurnal 
Change  of  Sea  Temperature,  922.— The  Fisheries,  925.— The  Sperm  Whale,  926. 

887.  There  is  a  movement  of  the  waters  of  the  ocean  which, 
though  it  be  a  translation,  yet  does  not  amount  to  what  is  known 
to  the  mariner  as  current,  for  our  nautical  instruments  and  the  art 
of  navigation  have  not  been  brought  to  that  state  of  perfection 
which  will  enable  navigators  generally  to  detect  as  currents  the 
flow  to  which  I  allude  as  drift 

888.  If  we  imagine  an  object  to  be  set  adrift  in  the  ocean  at  the 
equator,  and  if  we  suppose  that  it  be  of  such  a  nature  that  it  would 
obey  only  the  influence  of  sea  water,  and  not  of  the  winds,  this 
object,  I  imagine,  would,  in  the  course  of  time,  find  its  way  to  the 
icy  barriers  about  the  poles,  and  again  back  among  the  tepid  wa- 
ters of  the  tropics.  Such  an  object  would  illustrate  the  drift  of 
the  sea,  and  by  its  course  would  indicate  the  route  which  the  sur- 
face-waters of  the  sea  follow  in  their  general  channels  of  circula- 
tion to  and  fro  between  the  equator  and  the  poles. 

889.  The  object  of  Plate  IX.,  therefore,  is  to  illustrate,  as  far 
as  the  present  state  of  my  researches  enables  me  to  do,  the  cir- 
culation of  the  ocean,  as  influenced  by  heat  and  cold,  and  to  in- 
dicate the  routes  by  which  the  overheated  waters  of  the  torrid 
zone  escape  to  cooler  regions  on  one  hand,  and,  on  the  other,  the 
great  channel-ways  through  which  the  same  waters,  after  having 
been  deprived  of  this  heat  in  the  extra-tropical  or  polar  regions, 
return  again  toward  the  equator ;  it  being  assumed  that  the  drift 
or  flow  is  from  the  poles  when  the  temperature  of  the  surface 
water  is  helow,  and  from  the  equatorial  regions  when  it  is  above 
that  due  the  latitude.     Therefore,  in  a  mere  diagram,  as  this  plate 


THE  DRIFT  OF  THE  SEA.  309 

is,  tlie  numerous  eddies  and  local  currents  which  are  found  at  sea 
are  disregarded. 

890.  Of  all  the  currents  in  the  sea,  the  Gulf  Stream  is  the  best 
defined ;  its  limits,  especially  those  of  the  left  bank,  are  always 
well  marked,  and,  as  a  rule,  those  of  the  right  bank,  as  high  as  the 
parallel  of  the  thirty-fifth  degree  of  latitude,  are  quite  distinct,  be- 
ing often  visible  to  the  eye.  The  Gulf  Stream  shifts  its  channel 
(§  54),  but  nevertheless  its  banks  are  often  very  distinct.  As  I 
write  these  remarks,  the  abstract  log  of  the  ship  Herculean  (Will- 
iam M.  Chamberlain),  from  Callao  to  Hampton  Roads,  in  ^lay, 
1854,  is  received.  On  the  eleventh  of  that  month,  being  in  lati- 
tude 33°  39^  north,  longitude  74P  56'  west  (about  one  hundred 
and  thirty  miles  east  of  Cape  Fear),  he  remarks : 

891.  "Moderate  breezes,  smooth  sea,  and  fine  weather.  At  ten 
o'clock  fifty  minutes,  entered  into  the  southern  (right)  edge  of  the 
Stream,  and  in  eight  minutes  the  water  rose  six  degrees ;  the  edge 
of  the  stream  was  visible,  as  far  as  the  eye  could  see,  by  the  great 
rippling  and  large  quantities  of  Gulf  weed — more  '  weed'  than  I 
ever  saw  before,  and  I  have  been  many  times  along  this  route  in 
the  last  twenty  years." 

892.  In  this  diagram,  therefore,  I  have  thought  it  useless  to  at- 
tempt a  delineation  of  any  of  those  currents,  as  the  Rennell  Cur- 
rent of  the  North  Atlantic,  the  "  connecting  current"  of  the  South, 
"Mentor's  Counter  Drift,"  "Eossel's  Drift  of  the  South  Pacific," 
etc.,  which  run  now  this  way,  now  that,  and  which  are  frequently 
not  felt  by  navigators  at  all. 

893.  In  overhauling  the  log-books  for  data  for  this  chart,  I  have 
followed  vessels  with  the  water  thermometer  to  and  fro  across  the 
seas,  and  taken  the  registrations  of  it  exclusively  for  my  guide, 
without  regard  to  the  reported  set  X)f  the  currents.  When,  in  any 
latitude,  the  temperature  of  the  water  has  appeared  too  high  or  too 
low  for  that  latitude,  the  inference  has  been  that  such  water  was 
warmed  or  cooled,  as  the  case  may  be,  in  other  latitudes,  and  that 
it  has  been  conveyed  to  the  place  where  found  through  the  great 
channels  of  circulation  in  the  ocean.  If  too  warm,  it  is  supposed 
(§  889)  that  it  had  its  temperature  raised  in  warmer  latitudes,  and 
therefore  the  channel  in  which  it  is  found  leads  from  the  equato- 
rial regions. 


310  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

894.  On  the  other  hand,  if  the  water  be  too  cool  for  the  latitude, 
then  the  inference  is  that  it  has  lost  its  heat  in  colder  climates,  and 
therefore  is  found  in  channels  which  lead  from  the  polar  regions. 

895.  The  arrow-heads  point  to  the  direction  in  which  the  wa- 
ters are  supposed  to  flow.  Their  rate,  according  to  the  best  in- 
formation that  I  have  obtained,  is,  at  a  mean,  only  about  four  knots 
a  day — rather  less  than  more. 

896.  Accordingly,  therefore,  as  the  immense  volume  of  water  in 
the  Antarctic  regions  is  cooled  down,  it  commences  to  flow  north. 
As  indicated  by  the  arrow-heads,  it  strikes  against  Cape  Horn,  and 
is  divided  by  the  continent,  one  portion  going  along  the  west  coast 
as  Humboldt's  Current  (§  455) ;  the  other,  entering  the  South  At- 
lantic, flows  up  into  the  Gulf  of  Guinea,  on  the  coast  of  Africa. 
Now,  as  the  waters  of  this  polar  flow  approach  the  torrid  zone, 
they  grow  warmer  and  warmer,  and  finally  themselves  become  trop- 
ical in  their  temperature.  They  do  not  tlien,  it  may  be  supposed, 
stop  their  flow ;  on  the  contrary,  they  keep  moving,  for  the  very 
cause  which  brought  them  from  the  extra-tropical  regions  now  op- 
erates to  send  them  back.  This  cause  is  to  be  found  in  the  dif- 
ference of  the  specific  gravity  at  the  two  places.  If,  for  instance, 
these  waters,  when  they  commence  their  flow  from  the  hyperbo- 
rean regions,  were  at  30°,  their  specific  gravity  will  correspond  to 
that  of  sea  water  at  30°.  But  when  they  arrive  in  the  Gulf  of 
Guinea  or  the  Bay  of  Panama,  having  risen  by  the  way  to  80°, 
or  perhaps  85°,  their  specific  gravity  becomes  such  as  is  due  sea 
water  of  this  temperature ;  and,  since  fluids  difiering  in  specific 
gravity  can  no  more  balance  each  other  on  the  same  level  than 
can  unequal  weights  in  opposite  scales,  this  hot  water  must  now 
return  to  restore  that  equilibrium  which  it  has  destroyed  in  the 
sea  by  rising  from  30°  to  80°  or  85°. 

897.  Hence  it  will  be  perceived  that  these  masses  of  water 
which  are  marked  as  cold  are  not  always  cold.  They  gradually 
pass  into  warm  ;  for  in  traveling  from  the  poles  to  the  equator  they 
partake  of  the  temperature  of  the  latitudes  through  which  they 
flow,  and  grow  warm. 

898.  Plate  IX.,  therefore,  is  only  introduced  to  give  general 
ideas  ;  nevertheless,  it  is  very  instructive.     See  how  the  influx  of 


THE  DRIFT  OF  THE  SEA.  311 

cold  water  into  tlio  South  Atlantic  appears  to  divide  the  warm 
water,  and  squeeze  it  out  at  the  sides,  along  the  coasts  of  South 
Africa  and  Brazil.  So,  too,  in  the  JN'orth  Indian  Ocean,  the  cold 
water  again  compelling  the  warm  to  escape  along  the  land  at  the 
sides,  as  well  as  occasionally  in  the  middle. 

899.  In  the  North  Atlantic  and  North  Pacific,  on  the  contrary, 
the  warm  water  appears  to  divide  the  cold,  and  to  squeeze  it  out 
along  the  land  at  the  sides.  The  impression  made  loj  the  cold 
current  from  Baffin's  Bay  upon  the  Gulf  Stream  is  strikingly 
beautiful. 

900.  Why  is  it  that  these  polar  and  equatorial  waters  should 
appear  now  to  divide  and  now  to  be  divided  ?  The  Gulf  Stream 
has  revealed  to  us  a  fact  in  which  the  answer  is  involved.  We 
learn  from  that  stream  that  cold  and  warm  sea  waters  are,  in  a 
measure  (§  28),  like  oil  and  vinegar ;  that  is,  there  is  among  the 

.  particles  of  sea  water  at  a  high  temperature,  and  among  the  par- 
ticles of  sea  water  at  a  low  temperature,  a  peculiar  molecular  ar- 
rangement that  is  antagonistic  to  the  free  mixing  up  of  cold  and 
hot  together.  At  any  rate,  that  salt  waters  of  different  tempera- 
tures do  not  readily  intermingle  at  sea  is  obvious. 

901.  Does  not  this  same  repugnance  exist,  at  least  in  degree, 
between  these  bodies  of  cold  and  warm  water  of  the  plate  ?  And 
if  so,  does  not  the  phenomenon  we  are  considering  resolve  itself 
into  a  question  of  masses  ?  The  volume  of  warm  water  in  the 
North  Atlantic  is  greater  than  the  volume  of  cold  water  that  meets 
and  opposes  it ;  consequently,  the  warm  thrusts  the  cold  aside,  di- 
viding and  compelling  it  to  go  rouhd.  The  same  thing  is  repeat- 
ed in  the  North  Pacific,  whereas  the  converse  obtains  in  the  South 
Atlantic.  Here  the  great  pplar  flow,  after  having  been  divided  by 
the  American  Continent,  enters  die  Atlantic,  and  filling  up  nearly 
the  whole  of  the  immense  space  between  South  America  and  Af- 
rica, seems  to  press  the  warm  waters  of  the  tropics  aside,  compell- 
ing them  to  drift  along  the  coast  on  either  hand. 

902.  Another  feature  of  the  sea  expressed  by  this  plate  is  a  sort 
of  reflection  or  recast  of  the  shore-line  in  the  temperature  of  the 
water.  This  feature  is  most  striking  in  the  North  Pacific  and  In- 
dian Ocean.     The  remarkable  intrusion  of  the  cool  into  the  volume 


312  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

of  warm  waters  to  the  southward  of  the-  Aleutian  Islands,  is  not 
unlike  that  which  the  cool  waters  from  Davis's  Straits  make  in  the 
Atlantic  upon  the  Gulf  Stream.  In  sailing  through  this  "  horse- 
shoe," or  hend  in  the  Gulf  Stream  (§884),  Captain  N.  B.Grant, 
of  the  American  ship  Lady  Arbella,  bound  from  Hamburg  to  New 
York,  in  May,  1854,  passed,  from  daylight  to  noon,  twenty-four 
lars-e  "bera's,"  besides  several  small  ones,  "the  whole  ocean,  as 
far  as  the  eye  could  reach,  being  literally  covered  with  them.  I 
should,"  he  continues,  "judge  the  average  height  of  them  above 
the  surface  of  the  sea  to  be  about  sixty  feet ;  some  five  or  six  of 
them  were  at  least  twice  that  height,  and,  with  their  frozen  peaks 
jutting  up  in  the  most  fantastic  shapes,  presented  a  truly  sublime 
spectacle." 

903.  This  "horse-shoe"  of  cold  in  the  warm  water  of  the  North 
Pacific,  though  extending  5  degrees  farther  toward  the  south,  can 
not  be  the  harbor  for  such  icebergs.  The  cradle  of  those  of  the 
Atlantic  was  perhaps  in  the  Frozen  Ocean,  for  they  may  have 
come  thence  through  Baffin's  Bay.  But  in  the  Pacific  there  is  no 
nursery  for  them.  The  water  in  Behring's  Strait  is  too  shallow 
to  let  them  pass  from  that  ocean  into  the  Pacific,  and  the  climates 
of  Russian  America  do  not  favor  the  formation  of  large  bergs. 
But,  though  we  do  not  find  in  the  North  Pacific  the  physical  con- 
ditions which  generate  icebergs  like  those  of  the  Atlantic,  we  find 
them  as  abundant  with  fogs.  The  line  of  separation  between  the 
warm  and  cold  water  assures  us  of  these  conditions. 

904.  What  beautiful,  grand,  and  benign  ideas  do  we  not  see  ex- 
pressed in  that  immense  body  of  warm  waters  which  are  gathered 
together  in  the  middle  of  the  Pacific  and  Indian  Oceans  I  It  is 
the  womb  of  the  sea.  In  it,  coral  islands  innumerable  have  been 
fashioned,  and  pearls  formed  in  "great  heaps  ;"  there,  multitudes 
of  living  things,  countless  in  numbers  and  infinite  in  variety,  are 
hourly  conceived.  With  space  enough  to  hold  the  four  continents 
and  to  spare,  its  tepid  waters  teem  with  nascent  organisms.* 

*  "  It  is  the  realm  of  recf-liuilding  corals,  and  of  the  wondrously-beautiful  assem- 
blage of  animals,  vertebrate  and  invertebrate,  that  live  among  them  or  prey  upon  them. 
The  brightest  and  most  definite  arrangements  of  color  are  here  displayed.  It  is  the 
seat  of  maximum  development  of  the  majority  of  marine  genera.     It  has  but  few  re- 


THE  DRIFT  OF  THE  SEA. 


313 


Thej  sometimes  swarm  so  thickly  there  that  tliey  change  the  col- 
or of  the  sea,  makina;  it  crimson,  brown,  black,  or  white,  accorclinp- 
to  their  own  hues.  These  patches  of  colored  water  sometimes  ex- 
tend, especially  in  the  Indian  Ocean,  as  far  as  the  eye  can  reach. 
The  question,  "What  produces  them?"  is  one  that  has  elicited 
much  discussion  in  sea-faring  circles.  The  Brussels  Conference 
deemed  them  an  object  worthy  of  attention,  and  recommended  spe- 
cial observations  with  regard  to  them. 

905.  Capt.  W.  E.  Kingman,  of  the  American-  clipper  ship  the 
Shooting  Star,  reports  in  his  last  abstract  log  a  remarkable  white 
patch,  in  lat.  8°  46"  S.,  long.  105°  30"  E.,  and  which,  in  a  letter 
to  me,  he  thus  describes : 

"  Thursday,  July  27,  1854.  At  7h.  45m.  P.M.,  my  attention 
was  called  to  notice  the  color  of  the  water,  which  was  rapidly 
growing  white.  Knowing  that  we  were  in  a  much  frequented  part 
of  the  ocean,  and  having  never  heard  of  such  an  appearance  being 
observed  before  in  this  vicinity,  I  could  not  account  for  it.  I  im- 
mediately hove  the  ship  to  and  cast  the  lead ;  had  no  bottom  at 
60  fathoms.  I  then  kept  on  our  course,  tried  the  water  by  ther- 
mometer, and  found  it  to  be  78-|°,  the  same  as  at  8  A.M.  We 
filled  a  tub,  containing  some  60  gallons,  with  the  water,  and 
found  that  it  was  filled  with  small  luminous  particles,  which,  when 
stirred,  presented  a  most  remarkable  appearance.  The  whole  tub 
seemed  to  be  active  with  worms  and  insects,  and  looked  like  a 
grand  display  of  rockets  and  serpents  seen  at  a  great  distance  in 
a  dark  night ;  some  of  the  serpents  appeared  to  be  six  inches  in 
length,  and  very  luminous.  We  caught,  and  could  feel  them  in 
our  hands,  and  they  would  emit  light  until  brought  within  a  few 
feet  of  a  lamp,  when,  upon  looking  to  see  what  we  had,  behold 
nothing  was  visible ;  but,  by  the  aid  of  a  sextant's  magnifier,  we 
could  plainly  see  a  jelly-like  substance  without  color.  At  last,  a 
specimen  was  obtained  of  about  two  inches  in  length,  and  plainly 
visible  to  the  naked  eye  ;  it  was  about  the  size  of  a  large  hair,  and 

lations  of  identity  with  other  provinces.  The  Red  Sea  and  Persian  Gulf  are  its  off- 
sets."— From  Professor  Forbes's  Paper  on  the  *'  Distribution  of  Marine  Life."  Plate 
31st,  Johnston's  Physical  Atlas,  2d  ed. :  Wm.  Blackwood  &  Sons,  Edinburgh  and 
London,  1854. 


314  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

tapered  at  the  ends.  By  bringing  one  end  within  about  one 
fourth  of  an  inch  of  a  lighted  lamp,  the  flame  was  attracted  to- 
ward it,  and  burned  with  a  red  light ;  the  substance  crisped  in 
burning  something  like  a  hair,  or  appeared  of  a  red  heat  before 
being  consumed.  In  a  glass  of  the  water  there  were  several  small, 
round  substances  (say  xeth  of  an  inch  in  diameter),  which  had  the 
power  of  expanding  to  more  than  twice  their  ordinary  size,  and 
then  contracting  again;  when  expanded,  the  outer  rim  appeared 
like  a  circular  saw,  only  that  the  teeth  pointed  toward  the  centre. 

"  This  patch  of  white  water  was  about  23  miles  in  length,, north 
and  south,  divided  near  its  centre  by  an  irregular  strip  of  dark  wa- 
ter half  a  mile  wide ;  its  east  and  west  extent  I  can  say  nothing 
about. 

"  I  have  seen  what  is  called  white  water  in  about  all  the  known 
oceans  and  seas  in  the  world,  but  nothing  that  would  compare 
with  this  in  extent  or  whiteness.  Although  we  were  going  at  the 
rate  of  nine  knots,  the  ship  made  no  noise  either  at  the  bow  or 
stern.  The  whole  appearance  of  the  ocean  was  like  a  plain  cov- 
ered with  snow.  There  was  scarce  a  cloud  in  the  heavens,  yet  the 
sky,  for  about  ten  degrees  above  the  horizon,  appeared  as  black 
as  if  a  storm  was  raging ;  the  stars  of  the  first  magnitude  shone 
Yvdth  a  feeble  light,  and  the  '  IMilky  Way'  of  the  heavens  was  almost 
entirely  eclipsed  by  that  through  which  we  were  sailing.  The 
scene  was  one  of  awful  grandeur;  the  sea  having  turned  to  phos- 
phorus, and  the  heavens  being  hung  in  blackness,  and  the  stars 
going  out,  seemed  to  indicate  that  all  Nature  was  preparing  for 
that  last  grand  conflagration  which  we  are  taught  to  believe  is  to 
annihilate  this  material  world. 

"After  passing  through  the  patch,  we  noticed  that  the  sky,  for 
four  or  five  degrees  above  the  horizon,  was  considerably  illumin- 
ated, something  like  a  faint  aurora  borealis.  We  soon  passed  out 
of  sight  of  the  whole  concern,  and  had  a  fine  night,  without  any 
conflagration  (except  of  midnight  oil  in  trying  to  find  out  what 
was  in  the  water).  I  send  you  this,  because  I  believe  you  request 
your  corps  of  'one  thousand  assistants'  to  furnish  you  with  all  such 
items,  and  I  trust  it  will  be  acceptable.  But  as  to  its  furnishing 
3^ou  with  much,  if  any,  information  relative  to  the  insects  or  ani- 


THE  DRIFT  OF  THE  SEA. 


315 


mals  that  inhabit  the  mighty  deep,  time  will  only  tell ;  I  can  not 
think  it  will." 

906.  These  discolorations  are  no  doubt  caused  by  organisms 
of  the  sea,  but  whether  wholly  animal  or  wholly  vegetable,  or 
whether  sometimes  the  one  and  sometimes  the  other,  has  not  been 
satisfactorily  ascertained.  I  have  had  specimens  of  the  coloring 
matter  sent  to  me  from  the  pink-stained  patches  of  the  sea.  They 
were  animalcula3  well  defined.  The  tints  which  have  a'iven  to  the 
Eed  Sea  its  name  may,  perhaps,  be  in  some  measure  due  to  agen- 
cies similar  to  those  which,  in  the  salt-makers'  ponds,  give  a  red- 
dish cast  (§  3)  to  the  brine  just  before  it  reaches  that  point  of  con- 
centration when  crystallization  is  to  commence.  Some  micro- 
scopists  maintain  that  this  tinge  is  imparted  by  the  shells  and 
other  remains  of  infusoria  which  have  perished  in  the  growing 
saltness  of  the  water.  The  Hed  Sea  may  be  regarded,  in  a  cer- 
tain light,  as  the  scene  of  natural  salt-works  on  a  grand  scale. 
The  process  is  by  solar  evaporation.  'No  rains  interfere,  for  that 
sea  (§  404)  is  in  a  riverless  district,  and  the  evaporation  goes  on 
unceasingly,  day  and  night,  the  year  round.  The  shores  are 
lined  with  incrustations  of  salt,  and  the  same  causes  which  tinge 
with  red  (§  3)  the  brine  in  the  vats  of  the  salt-makers,  probably 
impart  a  like  hue  to  the  arms  and  ponds  a.long  the  shore  of  this 
sea.  Quantities,  also,  of  slimy,  red  coloring  matter  are,  at  certain 
seasons  of  the  year,  washed  up  along  the  shores  of  the  Red  Sea, 
which  Dr.  Ehrenberg,  after  an  examination  under  the  microscope, 
pronounces  to  be  a  very  delicate  kind  of  sea-weed :  from  this  mat- 
ter that  sea  derives  its  name.  So  also  the  Yellow  Sea.  Along 
the  coasts  of  China,  yellowish-colored  spots  are  said  not  to  be  un- 
common. I  know  of  no  examination  of  this  coloring  matter,  how- 
ever. In  the  Pacific  Ocean  I  have  often  observed  these  discolor- 
ations of  the  sea.  Red  patches  of  water  are  most  frequently  met 
with,  but  I  have  also  observed  white  or  milky  appearances,  which 
at  night  I  have  known  greatly  to  alarm  navigators  by  their  being 
taken  for  shoals. 

907.  These  teeming  waters  bear  off  through  their  several  chan- 
nels the  surplus  heat  of  the  tropics,  and  disperse  it  among  the 
icebergs  of  the  Antarctic.     See  the  immense  equatorial  flow  to  the 


316       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

east  of  New  Holland.  It  is  bound  for  the  icy  barriers  of  that  un- 
known sea,  there  to  temper  climates,  grow  cool,  and  return  again, 
refreshing  man  and  beast  by  the  way,  either  as  the  Humboldt 
Current,  or  the  ice-bearing  current  which  enters  the  Atlantic 
around  Cape  Horn,  and  changes  into  warm  again  as  it  enters  the 
Gulf  of  Guinea.  It  was  owing  to  this  great  southern  flow  from 
the  coral  regions  that  Captain  Hoss  was  enabled  to  penetrate  so 
much  farther  south  than  Captain  Wilkes,  on  his  voyage  to  the 
Antarctic,  and  it  is  upon  these  waters  that  that  sea  is  to  be  pen- 
etrated, if  ever.  The  North  Pacific,  except  in  the  narrow  passage 
between  Asia  and  America,  is  closed  to  the  escape  of  these  warm 
waters  into  the  Arctic  Ocean.  The  only  outlet  for  them  is  to  the 
south.  They  go  down  toward  the  Antarctic  regions  to  dispense 
their  heat  and  get  cool ;  and  the  cold  of  the  Antarctic,  therefore, 
it  may  be  inferred,  is  not  so  bitter  as  is  the  extreme  cold  of  the 
Frozen  Ocean  of  the  north. 

908. .  The  warm  flow  to  the  south  from  the  middle  of  the  In- 
dian Ocean  is  remarkable.  Masters  who  return  their  abstract 
logs  to  me  mention  sea-weed,  which  I  suppose  to  be  brought  down 
by  this  current,  as  far  as  45°  south.  There  it  is  generally,  but 
not  always,  about  5  degrees  warmer  than  the  ocean  along  the 
same  parallel  on  either  side. 

909.  But  the  most  unexpected  discovery  of  all  is  that  of  the 
warm  flow  along  the  west  coast  of  South  Africa,  its  junction  with 
the  Lagullas  current,  called,  higher  up,  the  Mozambique,  and  then 
their  starting  off  as  one  stream  to  the  southward.  The  prevalent 
opinion  used  to  be  that  the  Lagullas  current,  which  has  its  gene- 
sis in  the  Red  Sea  (§  440),  doubled  the  Cape  of  Good  Hope,  and 
then  joined  the  great  equatorial  current  of  the  Atlantic  to  feed  the 
Gulf  Stream.  But  my  excellent  friend,  Lieutenant  Marin  Jansen, 
of  the  Dutch  Navy,  suggested  that  this  was  probably  not  the  case. 
This  induced  a  special  investigation,  and  I  found  as  he  suggested, 
.and  as  is  represented  on  Plate  IX.  Captain  N.  B.  Grant,  in  the 
admirably  well-kept  abstract  log  of  his  voyage  from  New  York  to 
Australia,  found  this  current  remarkably  developed.  He  was  as- 
tonished at  the  temperature  of  its  waters,  and  did  not  know  how 
to  account  for  such  a  body  of  warm  water  in  such  a  place.    Being 


THE  DRIFT  OF  THE  SEA.  317 

in  longitude  14°  east,  and  latitude  39°  south,  lie  thus  writes  in 
his  abstract  log : 

910.  "  That  there  is  a  current  setting  to  the  eastward  across 
the  South  Atlantic  and  Indian  Ocean  is,  I  believe,  admitted  by  all 
navigators.  The  prevailing  westerly  winds  seem  to  oiFer  a  suiS- 
cient  reason  for  the  existence  of  such  a  current,  and  the  almost 
constant  southwest  swell  would  naturally  give  it  a  northerly  direc- 
tion. But  why  the  water  should  be  warmer  here  (38°  40^  south) 
than  between  the  parallels  of  35°  and  37°  south,  is  a  problem  that, 
in  my  mind,  admits  not  of  so  easy  solution,  especially  if  my  sus- 
picions are  true  in  regard  to  the  northerly  set.  I  shall  look  with 
much  interest  for  a  description  of  the  '  currents'  in  this  part  of  the 
ocean." 

911.  In  latitude  38°  south,  longitude  6°  east,  he  found  the  wa- 
ter at  56°.  His  course  thence  was  a  little  to  the  south  of  east,  to 
the  meridian  of  41°  east,  at  its  intersection  with  the  parallel  of 
42°  south.  Here  his  water  thermometer  stood  at  50°,  but  be- 
tween these  two  places  it  ranged  at  60°  and  upward,  being  as  high 
on  the  parallel  of  39°  as  73°.  Here,  therefore,  was  a  stream — a 
mighty  "river  in  the  ocean" — one  thousand  six  hundred  miles 
across  from  east  to  west,  having  water  in  the  middle  of  it  23° 
higher  than  at  the  sides.  This  is  truly  a  Gulf  Stream  contrast. 
What  an  immense  escape  of  heat  from  the  Indian  Ocean,  and 
what  an  influx  of  warm  water  into  the  frozen  regions  of  tlie  south! 
This  stream  is  not  always  as  broad  nor  as  warm  as  Captain  Grant 
found  it.  At  its  mean  stage  it  conforms  more  nearly  to  the  limits 
assigned  it  in  the  diagram  (Plate  IX.). 

912.  We  have,  in  the  volume  of  heated  water  reported  by  Cap- 
tain Grant,  who  is  a  close  and  accurate  observer,  an  illustration 
of  the  sort  of  sjyasviodic  efforts — the  heaves  and  throes — which  the 
sea,  in  the  performance  of  its  ceaseless  task,  has  sometimes  to 
make.  By  some  means,  the  equilibrium  of  its  waters,  at  the  time 
of  Captain  Grant's  passage,  December — the  southern  summer — 
1852,  appears  to  have  been  disturbed  to  an  unusual  extent ;  hence 
this  mighty  rush  of  overheated  waters  from  the  great  intertropical 
caldron  of  the  two  oceans  down  toward  the  south. 

913.  Instances  of  commotion  in  the  sea  at  uncertain  intervals 


318  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA 

— the  making,  as  it  were,  of  efforts  by  fits  and  starts  to  keep  up 
to  time  in  the  performance  of  its  manifold  offices — are  not  unfre- 
quent,  nor  are  they  inaptly  likened  to  spasms.  There  are  some 
remarkable  throes  in  the  sea  which  I  have  not  been  able  wholly 
to  account  for.  Near  the  equator,  and  especially  on  this  side  of 
it  in  the  Atlantic,  mention  is  made,  in  the  "  abstract  log,"  by  al- 
most every  observer  that  passes  that  way,  of  "tide-rips,"  which 
are  a  commotion  in  the  water,  not  unlike  that  produced  by  a  con- 
flict of  tides  or  of  other  powerful  currents.  These  "  tide-rips" 
sometimes  move  along  with  a  roaring  noise,  and  the  inexperienced 
navigator  always  expects  to  find  his  vessel  drifted  by  them  a  long 
way  out  of  her  course ;  but  when  he  comes  to  cast  up  his  reck- 
oning the  next  day  at  noon,  he  remarks  with  surprise  that  no  cur- 
rent has  been  felt. 

914.  These  tide-rips  are  usually  found  in  the  neighborhood  of 
the  equatorial  calms — that  region  of  constant  precipitation.  And 
hence,  if  currents  at  all — if  so,  they  are  very  superficial — I  have 
thought  they  might  be  streams  of  rain  water,  which  old  seamen 
tell  us  they  have  dipped  up  there  fresh  from  the  sea,  running  off. 
This  conjecture,  however,  does  not  satisfy  the  phenomenon  in  all 
of  its  aspects.  It  is  sometimes  described  as  starting  up  in  a  calm, 
and  then  approaching  the  vessel  with  great  waves  and  a  great 
noise ;  it  seems  threatening  enough  to  excite  a  feeling  of  appre- 
hension in  the  minds  of  seamen,  for  it  looks  as  if  it  would  dash 
over  their  frail  bark  as  it  lies  wallowing  in  the  sea,  and  helplessly 
flapping  its  sails  against  the  masts. 

915.  Captain  Higgins,  of  the  Maria,  when  bound  from  New 
York  to  Brazil,  thus  describes,  in  his  abstract  log,  one  of  these 
"tide-rips,"  as  seen  by  him,  10th  October,  1855,  in  N.  lat.  14°, 
W.  long.  34°  : 

"At  3  P.M.  saw  a  tide-rip;  in  the  centre,  temp,  air  80°,  wa- 
ter 81°.  From  the  time  it  was  seen  to  windward,  about  three  to 
five  miles,  until  it  had  passed  to  leeward  out  of  sight,  it  was  not 
five  minutes.  I  should  judge  it  traveled  at  not  less  than  sixty 
miles  per  hour,  or  as  fast  as  the  bores  of  India.  Althougli  we 
have  passed  through  several  during  the  night,  we  do  not  find  they 
have  set  the  ship  to  the  westward  any ;  it  may  be  that  they  are  so 


THE  DRIFT  OF  THE  SEA.  3I9 

soon  passed  that  tliey  have  no  influence  on  the  ship,  but  they  cer- 
tainly beat  very  hard  against  the  ship's  sides,  and  jarred  her  all  over. 
They  are  felt  even  when  below,  and  will  wake  one  out  of  sleep." 
916.  But  besides  tide-rips,  bores,  and  eagres,*  there  are  the 

*  The  bores  of  India,  of  the  Bay  of  Fundy,  and  the  Amazon  are  the  most  cele- 
brated. They  are  a  tremulous  tidal-wave,  which,  at  stated  periods,  comes  rolling  in 
from  the  sea,  threatening  to  overwhelm  and  ingulf  every  thing  that  moves  on  the 
beach.  This  wave  is  described,  especially  in  the  Bay  of  Fundy,  as  being  many  feet 
high  ;  and  it  is  said  oftentimes  to  overtake  deer,  swine,  and  other  wild  beasts  that  feed 
or  lick  on  the  beach,  and  to  swallow  them  up  before  the  swiftest  of  foot  among  them 
have  time  to  escape.  The  swine,  as  they  feed  on  muscles  at  low  water,  are  said  to 
snuff  the  "  bore,"  either  by  sound  or  smell,  and  sometimes  to  dash  off  to  the  cliffs  be- 
fore it  rolls  in. 

The  eagre  is  the  bore  of  Tsien-Tahg  river.  It  is  thus  described  by  Dr.  Maco-owan, 
in  a  paper  before  the  Royal  Asiatic  Society,  12th  January,  1853,  and  as  seen  by  him 
from  the  city  of  Hang-chau  in  1848  : 

"  At  the  upper  part  of  the  bay,  and  about  the  mouth  of  the  river,  the  eagre  is  scarce-, 
ly  observable ;  but,  owing  to  the  very  gradual  descent  of  the  shore,  and  the  rapidity 
of  the  great  flood  and  ebb,  the  tidal  phenomena  even  here  present  a  remarkable  ap- 
pearance. Vessels,  which  a  few  moments  before  were  afloat,  are  suddenly  left  high 
and  dry  on  a  strand  nearly  two  miles  in  width,  which  the  returning  wave  as  quickly 
floods.  It  is  not  until  the  tide  rushes  beyond  the  mouth  of  the  river  that  it  becomes 
elevated  to  a  lofty  wave  constituting  the  eagre,  which  attains  its  greatest  magnitude 
opposite  the  city  of  Hang-chau.  Generally  there  is  nothing  in  its  aspect,  except  on  the 
third  day  of  the  second  month,  and  on  the  eighteenth  of  the  eighth,  or  at  the  spring-tide, 
about  the  period  of  the  vernal  and  autumnal  equinoxes,  its  great  intensity  being  at  the 
latter  season.  Sometimes,  however,  during  the  prevalence  of  easterly  winds,  on  the 
third  day,  after  the  sun  and  moon  are  in  conjunction,  or  in  opposition,  the  eatrre 
courses  up  the  river  with  hardly  less  majesty  than  when  paying  its  ordinary  periodical 
visit.  On  one  of  these  unusual  occasions,  when  I  was  traveling  in  native  costume,  I 
had  an  opportunity  of  witnessing  it,  on  December  14th,  1848,  at  about  2  P.M. 

"  Between  the  river  and  the  city  walls,  which  are  a  mile  distant,  dense  suburbs  ex- 
tend several  miles  along  the  banks.  As  the  hour  of  flood-tide  approached,  crowds 
gathered  in  the  streets  running  at  right  angles  with  the  Tsien-Tang,  but  at  safe  dis- 
tances. My  position  was  a  terrace  in  front  of  the  Tf.i-wave  Temple,  which  afforded 
a  good  view  of  the  entire  scene.  On  a  sudden  all  trafiic  in  the  thronged  mart  was 
suspended,  porters  cleared  the  front  street  of  every  description  of  merchandise,  boat- 
men ceased  lading  and  unlading  their  vessels,  and  put  out  in  the  middle  of  the  stream, 
so  that  a  few  moments  sufficed  to  give  a  deserted  appearance  to  the  busiest  part  of 
one  of  the  busiest  cities  of  Asia.  The  centre  of  the  river  teemed  with  craft,  from 
small  boats  to  huge  barges,  including  the  gay  'flower-boats.'  Loud  shouting  from 
the  fleet  announced  the  appearance  of  the  flood,  which  seemed  like  a  glistening  white 
cable,  stretched  athwart  the  river  at  its  mouth,  as  far  down  as  the  eye  could  reach. 
Its  noise,  compared  by  Chinese  poets  to  that  of  thunder,  speedily  drowned  that  of  the 
boatmen  ;  and  as  it  advanced  with  prodigious  velocity — at  the  rate,  I  should  judge,  of 
twenty-five  miles  an  hour — it  assumed  the  appearance  of  an  alabaster  wall,  or,  rather, 


520       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA, 

sudden  disruption  of  the  ice  wliicli  arctic  voyagers  tell  of,  the  im- 
mense bergs  which  occasionally  appear  in  groups  near  certain  lat- 
itudes, the  variable  character  of  all  the  currents  of  the  sea — now 

of  a  cataract  four  or  five  miles  across,  and  about  thirty  feet  high,  moving  bodily  on- 
ward. Soon  it  reached  the  advanced  guard  of  the  immense  assemblage  of  vessels 
awaiting  its  approach.  Knowing  that  the  bore  of  the  Hooghly,  which  scarcely  de- 
served mention  in  connection  with  the  one  before  me,  invariably  overturned  boats 
which  were  not  skillfully  managed,  I  could  not  but  feel  apprehensive  for  the  lives  of 
the  floating  multitude.  As  the  foaming  wall  of  water  dashed  impetuously  onward, 
they  were  silenced,  all  being  intently  occupied  in  keeping  their  prows  toward  the 
wave  which  threatened  to  submerge  every  thing  afloat ;  but  they  all  vaulted,  as  it 
were,  to  the  summit  with  perfect  safety.  The  spectacle  was  of  greatest  interest  when 
the  eagre  had  passed  about  one  half  way  among  the  craft.  On  one  side  they  were 
quietly  reposing  on  the  surface  of  the  unruflled  stream,  while  those  on  the  nether 
portion  were  pitching  and  heaving  in  tumultuous  confusion  on  the  flood  ;  others  were 
scaling  with  the  agility  of  salmon  the  formidable  cascade.  This  grand  and  exciting 
scene  was  but  of  a  moment's  duration ;  it  passed  up  the  river  in  an  instant,  but  from 
this  point  with  gradually  diminishing  force,  size,  and  velocity,  until  it  ceased  to  be 
perceptible,  which  Chinese  accounts  represent  to  be  eighty  miles  distant  from  the 
city.  From  ebb  to  flood  tide  the  change  was  almost  instantaneous ;  a  slight  flood 
continued  after  the  passage  of  the  wave,  but  it  soon  began  to  ebb.  Having  lost  my 
memoranda,  I  am  obliged  to  write  from  recollection.  My  impression  is  that  the  fall 
was  about  twenty  feet ;  the  Chinese  say  that  the  rise  and  fall  is  sometimes  forty  feet 
at  Hang-chau.  The  maximum  rise  and  fall  at  spring-tides  is  probably  at  the  mouth 
of  the  river,  or  upper  part  of  the  bay,  where  the  eagre  is  hardly  discoverable.  In  the 
Bay  of  Fundy,  where  the  tides  rush  in  with  amazing  velocity,  there  is  at  one  place  a 
rise  of  seventy  feet ;  but  there  the  magnificent  phenomenon  in  question  does  not  ap- 
pear to  be  known  at  all.  It  is  not,  therefore,  where  tides  attain  their  greatest  rapid- 
ity, or  maximum  rise  and  fall,  that  this  wave  is  met  with,  but  where  a  river  and  its 
estuary  both  present  a  peculiar  configuration. 

"  Dryden's  definition  of  an  eagre,  appended  in  a  note  to  the  verse  above  quoted  from 
the  Threnodia  Augustalis,  is,  '  a  tide  swelling  above  another  tide,'  which  he  says  he 
had  himself  observed  in  the  River  Trent.  Such,  according  to  Chinese  oral  accounts, 
is  the  character  of  the  Tsien-Tang  tides — a  wave  of  considerable  height  rushes  sud- 
denly in  from  the  bay,  which  is  soon  followed  by  one  much  larger.  Other  accounts 
represent  three  successive  waves  riding  in  ;  hence  the  name  of  the  temple  mentioned, 
that  of  the  Three  Waves.  Both  here  and  on  the  Hooghly  I  observed  but  one  wave  ; 
my  attention,  however,  was  not  particularly  directed  to  this  feature  of  the  eagre.  The 
term  should,  perhaps,  be  more  comprehensive,  and  express  '  the  instantaneous  rise  and 
advance  of  a  tidal  wave  ;'  the  Indian  barbarism  '  bore'  should  be  discarded  altogether. 

"  A  very  short  period  elapsed  between  the  passage  of  the  eagre  and  the  resumption 
of  trafliic.  The  vessels  were  soon  attached  to  the  shore  again  ;  women  and  children 
were  occupied  in  gathering  articles  which  the  careless  or  unskillful  had  lost  in  the 
aquatic  melee.  The  streets  were  drenched  with  spray,  and  a  considerable  volume  of 
water  splashed  over  the  banks  into  the  head  of  the  grand  canal,  a  few  feet  distant." 
— ^Vide  Transactions  of  Chinese  Branch  of  the  Royal  Asiatic  Society. 


THE  DRIFT  OF  THE  SEA. 


321 


fast,  now  slow,  now  running  this  way,  then  that  —  all  of  which 
may  be  taken  as  so  many  signs  of  the  tremendous  throes  which 
occur  in  the  bosom  of  the  ocean.  Sometimes  the  sea  recedes  from 
the  shore,  as  if  to  gather  strength  for  a  great  rush  against  its  bar- 
riers, as  it  did  when  it  fled  back  to  join  with  the  earthquake  and 
overwhelm  Callao  in  1746,  and  again  Lisbon  nine  years  afterward. 
The  tide-rips  in  mid  ocean,  the  waves  dashing  against  the  shore, 
the  ebb  and  flow  of  tjie  tides,  may  be  regarded,  in  some  sense,  as 
the  throbbings  of  the  great  sea  pulse. 

917.  The  motions  of  the  Gulf  Stream  (§  55),  beating  time  for 
the  ocean  and  telling  the  seasons  for  the  whales,  also  suggest  the 
idea  of  a  pulse  in  the  sea,  which  may  assist  us  in  explaining  some 
of  its  phenomena.  At  one  beat  there  is  a  rush  of  warm  water  from 
the  equator  toward  the  poles,  at  the  next  beat  a  flow  from  the 
poles  toward  tlie  equator.  This  sort  of  pulsation  is  heard  also  in 
the  bowlings  of  the  storm  and  the  whistling  of  the  wind  ;  the  nee- 
dle trembles  unceasingly  to  it,  and  tells  us  of  magnetic  storms  of 
great  violence,  which  at  times  extend  over  large  portions  of  the 
earth's  surface ;  and  when  we  come  to  consult  the  records  of  those 
exquisitely  sensitive  anemometers,  which  the  science  and  ingenu- 
ity of  the  age  have  placed  at  the  service  of  philosophers,  we  find 
there  that  the  pulse  of  the  atmosphere  is  never  still :  in  what  ap- 
pears to  us  the  most  perfect  calm,  the  recording  pens  of  the  auto- 
matic machine  are  moving  to  the  pulses  of  the  air. 

918.  Now  if  we  may  be  permitted  to  apply  to  the  Gulf  Stream 
and  to  the  warm  flows  of  water  from  the  Indian  Ocean  an  idea 
suggested  by  the  functions  of  the  human  heart  in  the  circulation 
of  the  blood,  we  perceive  how  these  pulsations  of  the  great  sea- 
heart  may  perhaps  assist  in  giving  circulation  to  its  waters  through 
the  immense  system  of  aqueous  veins  and  arteries  that  run  between 
the  equatorial  and  polar  regions.  The  waters  of  the  Gulf  Stream, 
moving  together  in  a  body  (§1)  through  such  an  extent  of  ocean, 
and  being  almost  impenetrable  to  the  cold  waters  on  either  side — 
which  are,  indeed,  the  banks  of  this  mighty  river — may  be  com- 
pared to  a  wedge-shaped  cushion  placed  between  a  wall  of  waters 
on  the  right  and  a  wall  of  waters  on  the  left.  If  now  we  imagine 
the  equilibrium  of  the  sea  to  be  disturbed  by  the  heating  or  cool- 


322  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

ing  of  its  waters  to  the  right  or  the  left  of  this  stream,  or  the  freez-. 
ing  or  thawing  of  them  in  any  part,  or  if  we  imagine  the  disturb-^ 
ance  to  take  place  hy  the  action  of  any  of  those  agencies  which 
give  rise  to  the  motions  which  we  have  called  the  pulsations  of 
the  sea,  we  may  conceive  how  it  might  be  possible  for  them  to 
force  the  wall  of  waters  on  the  left  to  press  this  cushion  down  to- 
ward the  south,  and  then  again  for  the  wall  on  the  right  to  press 
it  back  again  to  the  north,  as  (§  56)  we  hav§  seen  that  it  is. 

919.  Now  the  Gulf  Stream,  with  its  head  in  the  Straits. of 
Florida,  and  its  tail  in  the  midst  of  the  ocean,  is  wedge-shaped; 
its  waters  cling  together,  and  are  pushed  to  and  fro — squeezed, 
if  you  please — by  a  pressure  (§  55),  now  from  the  right,  then  from 
the  left,  so  as  to  work  the  whole  wedge  along  between  the  cold 
liquid  walls  which  contain  it.  ]May  not  the  velocity  of  this 
stream,  therefore,  be  in  some  sort  the  result  of  this  working  and 
twisting,  this  peristaltic  force  in  the  sea  ? 

920.  In  carrying  out  the  views  suggested  by  the  idea  of  pulsa- 
tions in  the  sea,  and  their  effects  in  giving  dynamical  force  to  the 
circulation  of  its  waters,  attention  may  be  called  to  the  two  lobes 
of  polar  waters  that  stretch  up  from  the  south  into  the  Indian 
Ocean,  and  which  are  separated  by  a  feeble  flow  of  tropical  wa-^ 
ters.  Icebergs  are  sometimes  met  with  in  these  polar  waters  as 
high  up  as  the  parallel  of  the  fortieth  degree  of  latitude.  Now, 
considering  that  this  tropical  flow  in  mid-ocean  is  not  constant — 
that  many  navigators  cross  the  path  assigned  to  it  in  the  plate 
without  finding  their  thermometer  to  indicate  any  increase  of  heat 
in  the  sea ;  and  considering,  therefore,  that  any  unusual  flow  of 
polar  waters,  any  sudden  and  extensive  disruption  of  the  ice  there, 
sufficient  to  cause  a  rush  of  waters  thence,  would  have  the  effect 
of  closing  for  the  time  this  mid-ocean  flow  of  tropical  waters,  we 
are  entitled  to  infer  that  there  is  a  sort  of  conflict  at  times  going 
on  in  this  ocean  between  its  polar  and  equatorial  flows  of  water. 
For  instance,  a  rush  of  waters  takes  place  from  the  poles  toward 
the  equator.  The  two  lobes  close,  cut  off  the  equatorial  flow 
between  them,  and  crowd  the  Indian  Ocean  with  polar  waters. 
They  press  out  the  overheated  waters  ;  hence  the  great  equatorial 
flow  encountered  by  Captain  Grant. 


THE  DRIFT  OF  THE  SEA.  323 

Thus  this  opening  between  the  cold-water  lobes  appears  to  hold 
to  the  chambers  of  the  Indian  Ocean,  with  their  heated  waters, 
the  relations  which  the  valves  and  the  ventricles  of  the  human 
h-eart  hold  to  the  circulation  of  the  blood.  The  closing  of  these 
lobes  at  certain  times  prevents  regurgitation  of  the  warm  waters, 
and  compels  them  to  pass  through  their  appointed  channels. 

921.  From  this  point  of  view,  how  many  new  beauties  do  not 
now  begin  to  present  themselves  in  the  machinery  of  the  ocean! 
its  great  heart  not  only  beating  time  to  the  seasons,  but  palpitat- 
ing also  to  the  winds  and  the  rains,  to  the  cloud  and  the  sun- 
shine, to  day  and  night  (§  864).  Few  persons  have  ever  taken  the 
trouble  to  compute  how  much  the  fall  of  a  single  inch  of  rain  over 
an  extensive  region  in  the  sea,  or  how  much  the  change  even  of  two 
or  three  degrees  of  temperature  over  a  few  thousand  square  miles 
of  its  surface,  tends  to  disturb  its  equilibrium,  and  consequently 
to  cause  an  aqueous  palpitation  that  is  felt  from  the  equator  to  the 
poles.  Let  us  illustrate  by  an  example  :  The  surface  of  the  At- 
lantic Ocean  covers  an  area  of  about  twenty-five  millions  of  square 
miles.  Now,  let  us  take  one  fifth  of  this  area,  and  suppose  a  fall 
of  rain  one  inch  deep  to  take  place  over  it.  This  rain  would  weigh 
three  hundred  and  sixty  thousand  millions  of  tons ;  and  the  salt 
which,  as  water,  it  held  in  solution  in  the  sea,  and  which,  when 
that  water  was  taken  up  as  vapor,  was  left  behind  to  disturb  equi- 
librium, weighed  sixteen  millions  more  of  tons,  or  nearly  twice  as 
much  as  all  the  ships  in  the  world  could  carry  at  a  cargo  each.  It 
might  fall  in  an  hour,  or  it  might  fall  in  a  day ;  but,  occupy  what 
time  it  might  in  falling,  this  rain  is  calculated  to  exert  so  much 
force — which  is  inconceivably  great — in  disturbing  the  equilibrium 
of  the  ocean.  If  all  the  water  discharged  by  the  Mississippi  River 
during  the  year  were  taken  up  in. one  mighty  measure,  and  cast 
into  the  ocean  at  one  efibrt,  it  would  not  make  a  greater  disturb* 
ance  in  the  equilibrium  of  the  sea  than  would  the  fall  of  rain  sup- 
posed. Now  this  is  for  but  one  fifth  of  the  xltlantic,  and  the  area 
of  the  Atlantic  is  about  one  fifth  of  the  sea-area  of  the  world ; 
and  the  estimated  fall  of  rain  was  but  one  inch,  whereas  the  aver- 
age for  the  year  is  (§  208)  sixty  inches,  but  we  will  assume  it  for 
the  sea  to  be  no  more  than  thirty  inches.     In  the  aggregate,  and 

X 


324       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

on  an  average,  then,  such  a  disturbance  in  the  equilibrium  of  the 
whole  ocean  as  is  here  supposed  occurs  seven  hundred  and  fifty 
times  a  year,  or  at  the  rate  of  once  in  twelve  hours.  Moreover, 
when  it  is  recollected  that  these  rains  take  place  now  here,  now 
there  ;  that  the  vapor  of  which  they  were  formed  was  taken  up  at 
still  other  places,  we  shall  be  enabled  to  appreciate  the  better  the 
force  and  the  effect  of  these  pulsations  in  the  sea. 

922.  Between  the  hottest  hour  of  the  day  and  the  coldest  hour 
of  the  night  there  is  frequently  a  change  of  four  degrees  in  the 
temperature  of  the  sea.*  Let  us,  therefore,  the  more  thoroughly 
to  appreciate  the  throbbings  of  the  sea-heart,  which  take  place  in 
consequence  of  the  diurnal  changes  in  its  temperature,  call  in  the 
sunshine,  the  cloud  without  rain,  with  day  and  night,  and  their 
heating  and  radiating  processes.  And  to  make  the  case  as  strong 
as  to  be  true  to  nature  we  may,  let  us  again  select  one  fifth  of 
the  Atlantic  Ocean  for  the  scene  of  operation.  The  day  over  it  is 
clear,  and  the  sun  pours  down  his  rays  with  their  greatest  intensi- 
ty, and  raises  the  temperature  two  degrees.  At  night  the  clouds 
interpose,  and  prevent  radiation  from  this  fifth,  whereas  the  re- 
maining four  fifths,  which  are  supposed  to  have  been  screened  by 
clouds,  so  as  to  cut  off  the  heat  from  the  sun  during  the  day,  are 
now  looking  up  to  the  stars  in  a  cloudless  sky,  and  serve  to  lower 
the  temperature  of  the  surface-waters,  by  radiation,  two  degrees. 
Here,  then,  is  a  difference  of  four  degrees,  which  we  will  suppose 
extends  only  ten  feet  below  the  surface.  The  total  and  absolute 
change  made  in  such  a  mass  of  sea  water  by  altering  its  temper- 
ature two  degrees,  is  equivalent  to  a  change  in  its  volume  of  three 
hundred  and  ninety  thousand  millions  of  cubic  feet. 

923.  Do  not  the  clouds,  night  and  day,  now  present  themselves 
to  us  in  a  new  light  ?  They  are  cogs,  and  rachets,  and  wheels  in 
that  grand  and  exquisite  machinery  which  governs  the  sea,  and 
which,  amid  all  the  jarring  of  the  elements,  preserves  in  harmony 
the  exquisite  adaptations  of  the  ocean. 

924.  It  seems  to  be  a  physical  law,  that  cold-water  fish  are  more 
edible  than  those  of  warm  water.  Bearing  this  fact  in  mind  as 
we  study  Plate  IX.,  we  see  at  a  glance  the  places  which  are  most 

*  Vide  Admiral  Smyth's  Memoir  of  the  Mediterranean,  p.  125. 


THE  DRIFT  OF  THE  SEA.  325 

favored  with  good  fisli-markets.  Botli  shores  of  North  America, 
the  east  coast  of  China,  with  the  west  coasts  of  Europe  and  South 
America,  are  all  washed  by  cold  waters,  and  therefore  we  may  in- 
fer that  their  markets  abound  with  the  most  excellent  fish.  The 
fisheries  of  Newfoundland  and  New  England,  over  which  nations 
have  wrangled  for  centuries,  are  in  the  cold  water  from  Davis's 
Strait.  The  fisheries  of  Japan  and  Eastern  China,  which  almost, 
if  not  quite,  rival  these,  are  situated  also  in  the  cold  water. 

Neither  India,  nor  the  east  coasts  of  Africa  and  South  America, 
where  the  warm  waters  are,  are  celebrated  for  their  fish. 

925.  Three  thousand  American  vessels,  it  is  said,  are  engaged 
in  the  fisheries.  If  to  these  we  add  the  Dutch,  French,  and  En- 
glish, we  shall  have  a  grand  total,  perhaps,  of  not  less  than  six  or 
eight  thousand,  of  all  sizes  and  flags,  engaged  in  this  one  pursuit. 
Of  all  the  industrial  pursuits  of  the  sea,  however,  the  whale  fish- 
ery is  the  most  valuable.  Wherefore,  in  treating  of  the  physical 
geography  of  the  sea,  a  map  for  the  whales  would  be  useful. 

926.  The  sperm  whale  is  a  warm-water  fish.  The  right  whale 
delights  in  cold  water.  An  immense  number  of  log-books  of  whal- 
ers have  been  discussed  at  the  National  Observatory,  with  the 
view  of  detecting  the  parts  of  the  ocean  in  which  the  whales  are 
to  be  found  at  the  different  seasons  of  the  year.  Charts  showing 
the  result  have  been  published ;  they  form  a  part  of  the  series  of 
Maury's  Wind  and  Current  Charts. 

927.  In  the  course  of  these  investigations,  the  discovery  was 
made  that  the  torrid  zone  is,  to  the  right  whale,  as  a  sea  of  fire, 
through  which  he  can  not  pass  ;  that  the  right  whale  of  the  north- 
ern hemisphere  and  that  of  the  southern  are  two  different  animals ; 
and  that  the  sperm  whale  has  never  been  known  to  double  the 
Cape  of  Good  Hope — he  doubles  Cape  Horn. 

928.  With  these  remarks,  and  the  explanations  given  on  Plate 
IX.,  the  parts  of  the  ocean  to  which  the  right  whale  most  resorts, 
and  the  parts  in  which  the  sperm  are  found,  may  be  seen  at  a 
glance. 


326   .     THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTER  XYII. 

STORMS. 

Data  for  Plate  V.,  ^  929. — Typhoons,  936.— Monsoons  in  the  China  Sea,  937.— Mau- 
ritius Hurricanes,  938. — West  India,  ditto,  939. — Jansen  on  Hurricanes  and  Cy- 
clones, 940. — Extra-tropical  Gales,  950. — The  Steamer  San  Francisco's  Gale,  951. — 
More  Rains,  Gales,  &c.,  in  the  North  than  in  the  South  Atlantic  (Plate  XHL),  956. 

929.  Plate  Y.  is  constructed  from  data  furnished  by  tlie  Pilot 
Charts,  as  far  as  they  go,  that  are  in  process  of  construction  at  the 
National  Observatory.  For  the  Pilot  Charts,  the  whole  ocean  is 
divided  off  into  "fields"  or  districts  of  five  degrees  square,  i.  e., 
five  degrees  of  latitude  by  five  degrees  of  longitude,  as  already  ex- 
plained on  page  23.  Now,  in  getting  out  from  the  log-books  ma- 
terials for  showing,  in  every  district  of  the  ocean,  and  for  every 
month,  how  navigators  have  found  the  winds  to  blow,  it  has  been 
assumed  that,  in  whatever  part  of  one  of  these  districts  a  navigator 
may  be  when  he  l:ecords  the  direction  of  the  wind  in  his  log,  from 
that  direction  the  wind  was  blowing  at  that  time  all  over  that  dis- 
trict ;  and  this  is  the  only  assumption  that  is  permitted  in  the 
whole  course  of  investigation. 

930.  Now  if  the  navigator  will  draw,  or  imagine  to  be  drawn  in 
any  such  district,  twelve  vertical  columns  for  the  twelve  months, 
and  then  sixteen  horizontal  lines  through  the  same  for  the  sixteen 
points  of  the  compass,  i.  e.,  for  N.,  N.N.E.,  N.E.,  E.N.E.,  and  so 
on,  omitting  the  %-points,  he  will  have  before  him  a  picture  of 
the  "Investigating  Chart,"  out  of  which  the  "Pilot  Charts"  are 
constructed.  In  this  case,  the  alternate  points  of  the  compass 
only  are  used,  because,  when  sailing  free,  the  direction  of  the 
wind  is  seldom  given  for  such  points  as  N.  %  E.,  W.  b?j  S.,  &c. 
Moreover,  any  attempt,  for  the  present,  at  greater  nicety  would  be 
over-refinement ;  for  navigators  do  not  always  make  allowance  for 
the  aberration  of  the  wind ;  in  other  words,  they  do  not  allow  for 
the  apparent  change  in  the  direction  of  the  wind  caused  by  the 


STORMS.  327 

rate  at  wlilcli  the  vessel  may  be  moving  througli  the  water,  and 
the  angle  which  her  course  makes  with  the  true  direction  of  the 
wind.  Bearing  this  explanation  in  mind,  the  intelligent  navigator 
will  have  no  difficulty  in  understanding  the  wind  diagram  (Plate 
v.),  and  in  forming  a  correct  opinion  as  to  the  degree  of  credit  due 
to  the  fidelity  with  which  the  prevailing  winds  of  the  year  are  rep- 
resented on  Plate  VIII. 

931.  As  the  compiler  wades  through  log-book  after  log-book, 
and  scores  down  in  column  after  column,  and  upon  line  after  line, 
mark  upon  mark,  he  at  last  finds  that,  imder  the  month  and  from 
the  course  upon  which  he  is  about  to  make  an  entry,  he  has  al- 
ready made  four  marks  or  scores,  thus  ( H  1 1 ).  The  one  that  he 
has  now  to  enter  will  make  the  fifth,  and  he  "scores  and  tallies," 
and  so  on  until  all  the  abstracts  relating  to  that  part  of  the  ocean 
upon  which  he  is  at  work  have  been  gone  over,  and  his  materials 
exhausted.     These  "fives  and  tallies"  are  exhibited  on  Plate  V. 

932.  Now,  with  this  explanation,  it  wiU  be  seen  that  in  the 
district  marked  A  (Plate  V.)  there  have  been  examined  the  logs  of 
vessels  that,  giving  the  direction  of  the  wind  for  every  eight  hours, 
have  altogether  spent  days  enough  to  enable  me  to  record  the  calms 
and  the  prevailing  direction  of  the  winds  for  eight  hours,  2144 
times :  of  these,  285  were  for  the  month  of  September ;  and  of 
these  285  observations  for  September,  the  wind  is  reported  as  pre- 
vailing for  as  much  as  eight  hours  at  a  time:  from  N.,  3  times ; 
fromN.N.E.,  1;  N.E.,  2;  E.KE.,  1;  E.,0;  E.S.E.,  1;  S.E.,4; 
S.S.E.,  2;  S.,  25;  S.S.W.,  45;  S.W.,  93 ;  W.S.W.,  24;  W., 
47;  W.N.W.,  17;  KW.,  15;  N.N.W.,  1;  Calms  (the  little  O's), 
5 ;  total,  285  for  this  month  in  this  district. 

The  number  expressed  in  figures  denotes  the  whole  number  of 
observations  of  calms  and  winds  together  that  are  recorded  for 
each  month  and  district. 

934.  In  C,  the  wind  in  May  sets  one  third  of  the  time  from 
west.  But  in  A,  which  is  between  the  same  parallels,  the  favor- 
ite quarter  for  the  same  month  is  from  S.  to  vS.W.,  the  wind  set- 
ting one  third  of  the  time  from  that  quarter,  and  only  10  out  of 
221  times  from  the  west ;  or,  on  the  average,  it  blows  from  the 
west  only  1|  day  during  the  month  of  May. 


328  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

935.  In  B,  notice  tlie  great  "  Sun  Swing"  of  tlie  winds  in  Sep- 
tember, indicating  that  the  change  from  summer  to  winter,  in  that 
region,  is  sudden  and  violent ;  from  winter  to  summer,  gentle  and 
gradual. 

In  some  districts  of  the  ocean,  mbre  than  a  thousand  observa- 
tions have  been  discussed  for  a  single  month,  whereas,  with  regard 
to  others,  not  a  single  record  is  to  be  found  in  any  of  the  numer- 
ous log-books  at  the  National  Observatory. 

936.  Typhoons. — The  China  Seas  are  celebrated  for  their  furi- 
ous gales  of  wind,  known  among  seamen  as  typhoons  and  white 
squalls.  These  seas  are  included  on  the  plate  (YIII.)  as  within 
the  region  of  the  monsoons  of  the  Indian  Ocean.  But  the  mon- 
soons of  the  China  Sea  are  not  five-month  monsoons  (§  788) ; 
they  do  not  prevail  from  the  west  of  south  for  more  than  two  or 
three  months. 

937.  Plate  V.  exhibits  the  monsoons  very  clearly  in  a  part  oi 
this  sea.  In  the  square  between  15°  and  20°  north,  110°  and 
115°  east,  there  appears  to  be  a  system  of  three  monsoons;  that 
is,  one  from  northeast  in  October,  November,  December,  and  Jan- 
uary ;  one  from  east  in  ]\Iarch  and  April,  changing  in  ]\Iay  ;  and 
another  from  the  southward  in  June,  July,  and  August,  changing 
in  September.  The  great  disturber  of  the  atmospheric  equilibrium 
appears  to  be  situated  among  the  arid  plains  of  Asia  ;  their  influ- 
ence extends  to  the  China  Seas,  and  about  the  changes  of  the 
monsoons  these  awful  gales,  called  typhoons  and  white  squalls,  are 
experienced. 

938.  In  like  manner,  the  ]\Iauritius  hurricanes,  or  the  cyclones 
of  the  Indian  Ocean,  occur  during  the  unsettled  state  of  the  at- 
mospheric equilibrium  which  takes  place  at  that  debatable  period 
daring  the  contest  between  the  trade-wind  force  and  the  monsoon 
force  (§  796),  and  which  debatable  period  occurs  at  the  changing 
of  the  monsoon,  and  before  either  force  has  completely  gained  or 
lost  the  ascendency.  At  this  period  of  the  year,  the  winds, 
breaking  loose  from  their  controlling  forces,  seem  to  rage  with  a 
fiiry  that  would  break  up  the  very  fountains  of  the  deep. 

939.  So,  too,  with  the  West  India  hurricanes  of  the  Atlantic. 
These  winds  are  most  apt  to  occur  during  the  months  of  August 


STORMS.  329 

and  September.  There  is,  therefore,  this  remarkable  difference 
between  these  gales  and  those  of  the  East  Indies  :  the  latter  occur 
about  the  changing  of  the  monsoons,  the  former  during  their  height. 
In  August  and  September,  the  southwest  monsoons  of  Africa  (§ 
810)  and  the  southeast  monsoons  of  the  West  Indies  (§  787)  are 
at  their  height ;  the  agent  of  one  drawing  the  northeast  trade- 
winds  from  the  Atlantic  into  the  interior  of  New  Mexico  and  Tex- 
as, the  agent  of  the  other  drawing  them  into  the  interior  of  Africa. 
Its  two  forces,  pulling  in  opposite  directions,  assist  now  and  then 
to  disturb  the  atmospheric  equilibrium  to  such  an  extent  that  the 
most  powerful  revulsions  in  the  air  are  required  to  restore  it. 

940.  "The  hurricane  season  in  the  North  Atlantic  Ocean,"  savs 
Jansen,  ' '  occurs  simultaneously  with  the  African  monsoons,  and  in 
the  same  season  of  the  year  in  which  the  monsoons  prevail  in  the 
North  Indian  Ocean,  in  the  China  Sea,  and  upon  the  western  coast 
of  Central  America,  all  the  seas  of  the  northern  hemisphere  have 
the  hurricane  season.  On  the  contrary,  the  South  Indian  Ocean 
has  its  hurricane  season  in  the  opposite  season  of  the  year,  and  when 
the  northwest  monsoon  prevails  in  the  East  Indian  Archipelago. 

941.  "  In  the  South  Pacific  and  in  the  South  Atlantic,  so  far  as 
I  know,  rotatory  storms  are  never  known,  and  these  seas  have  no  . 
monsoons.  Such  a  coincidence  of  hurricanes  with  monsoons,  and 
of  the  hurricane-season  with  the  monsoon-season,  is  not  without 
signification.  It  ever  gives  rise  to  the  thought  that  the  one  dis- 
turbance causes  the  other ;  and  however  terrible  the  hurricanes  may 
be  to  us,  however  disastrous  they  may  appear,  yet  we  are  compelled 
to  acknowledge  therein  the  healthful  working  of  Nature  which  is 
compensating  over  all  and  in  all.  "We  need  not,  then,  doubt  that 
these  revolving  storms  have  a  determinate  task  to  perform  in  the 
economy  of  nature — a  task  which  they  can  not  otherwise  fulfill 
save  by  rotations ;  and  certainly  it  is  good  that  they  restore  in 
proportion  to  the  terrible  power  wherewith  they  are  intrusted. 

942.  "  We  do  not  know  all  the  disturbances  which  are  caused 
by  the  land  in  the  condition  of  the  atmosphere.  '  The  way  of  the 
lightning  of  the  thunder'  is  to  us  all  unknown.  The  circulating 
channels  of  electricity  are  as  yet  hidden  in  a  deep  night. 

943.  "Neither  do  we  know  what  influence  the  land  and  the 


330  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

warm  currents  in  the  sea  have  thereon,  even  less  than  we  know 
what  operations  are  appointed  for  the  hurricanes  in  the  economy 
of  nature  ;  but  that  they,  in  their  way,  have  important  services  to 
perform,  can  not  be  doubted.  The  almighty  and  merciful  Wis- 
dom, whom  we  find  universally  in  all  the  operations  of  nature, 
assures  us  thereof — is  to  us  a  pledge.  The  fact  that  the  hurricanes 
prefer  to  place  their  feet  in  warm  water,  and  that  in  all  seas  where 
they  prevail  warm  settled  currents  are  also  found,  which  appear  to 
arise  from  the  disturbance  which  the  solid  crust  of  the  earth 
causes  in  the  regular  flowing  of  the  waters  of  the  sea,  causes  us 
to  suspect  that  there  is  a  certain  relation  between  the  hurricanes 
and  the  warm  currents ;  and,  finally,  that  in  the  economy  of  na- 
ture the  hurricanes  in  the  atmosphere  and  the  warm  'rivers  in 
the  sea'  work  together  to  restore  the  disturbed  equilibrium  in  na- 
ture, which  can  be  done  in  no  other  way  than  this,  and  along  the 
way,  which  they,  as  it  were,  mutually  agree  to  follow  together. 
Thus  we  see  the  hurricanes  beyond  the  tropics  follow  the  most 
prevailing  current  of  air  along  the  surface,  on  one  side  from  the 
southwest,  on  the  other  side  from  the  northwest,  just  as  the  Gulf 
Stream  flows  to  the  north  and  east,  and  the  warm  currents  of  the 
South  Indian  Ocean  to  the  south  and  east,  and,  again,  the  China 
current  to  the  north  and  east.  In  this  we  see,  again,  the  universal 
laws  by  which  all  matter  is  governed :  very  touching  is  the  sim- 
plicity of  the  Divine  plan. 

944.  "When  the  hurricanes  and  the  'rivers  in  the  sea,'  upon 
their  way  to  the  poles,  have  reached  the  parallel  of  latitude  upon 
which  the  effort  of  the  diurnal  revolution  of  the  earth  upon  her 
axis  causes  air  and  water  to  be  forced  in  a  northeasterly  or  south- 
easterly direction,  then  they  bow  themselves  submissively  to  the 
law,  and  go  together,  often  hand  in  hand,  to  accomplish  their  ap- 
pointed tasks.  And  now,  if  we  suppose  that  by  the  diurnal  rev- 
olution every  thing  which  moves  from  the  equator  to  this  parallel 
of  latitude  is  bent  more  gradually  to  the  east,  then  it  is  remarka- 
ble that  the  first  part  of  the  course  of  circulating  storms  often 
stands  perpendicular  to  these  supposed  movements  of  the  air,  and 
in  the  North  Atlantic  Ocean  runs  nearly  W.N.W. ;  in  the  South 
Indian  Ocean,  W.S.W. 


STORMS.  332 

945.  "Hurricanes  arc  sometimes  observed  upon  the  limits  of 
the  African  monsoon,  and  upon  the  limits  of  the  monsoon  of  the 
East  Indian  Archipelago.  In  this  Archipelago  right  heavy  spouts 
are  seldom  seen.  Hurricanes  never  have  been  observed  in  the 
southern  hemisphere,  between  88°  and  90°  east  longitude ;  they 
are  also  found  in  September  in  13°  north  latitude  and  29°  west 
lono'itudc,  and  in  16°  33^  north  latitude  and  24°  20'  west  lonsri- 
tude  ;  the  latter  also  in  18°  north  latitude  and  25°  west  longitude, 
and  in  16°  30'  north  latitude  and  26°  40'  west  longitude;*  yet 
not  in  the  monsoon — so  much  is  known  to  me — but  riglit  ujoon 
its  limits ;  also  in  the  equatorial  belt  which  wavers  about  the 
monsoon,  and  which  becomes  narrower  and  narrower  as  it  recedes 
from  the  equator. 

946,  "Now,  when  we  remember  what  is  said  (§  820)  of  the^ 
spring  changing  in  the  southern  hemisphere,  which  agrees  with 
the  autumnal  changing  in  the  northern  hemisphere,  and  think  of 
the  combat  whicli  is  then  so  manifestly  waged  between  the  vari- 
ous currents  of  air  and  the  numerous  spouts  whicli  arise  in  the 
East  Indian  Archipelago  by  the  aid  of  small  groups  of  islands, 
then  we  shall  be  less  surprised  to  iind  a  similar  effect  produced 
upon  the  limit  of  the  African  monsoon,  especially  when  it  pushes- 
the  equatorial  belt  of  calms  quite  over  to  a  portion  of  the  Cape 
Verd  Islands.  When  we  take  into  account  that  this  belt  becomes 
narrower  and  narrower  as  it  is  removed  from  the  equator — that  also 
the  different  currents  of  air,  which  draw  in  opposite  directions,  lie 
closer  to  each  other — that  the  southwest  and  northwest  winds  ap- 
proach very  near  to  each  other,  and  that  the  latter,  in  August  and 
September,  are  deflected  out  of  their  course  by  the  heights  of  the 
Cape  Verd  Islands,  then  not  much  more  is  necessary  to  enable 
one  to  comprehend  why  a  wind  which,  coming  from  the  north- 
east, and  veering  by  the  north  around  to  the  northwest,  should, 
as  it  meets  the  southwest  winds,  make  a  complete  revolution, 
and  in  so  doing  form  a  whirlwind,  which  would  go  traveling 
through  the  northeast  trade-wind,  especially  when  the  moisture 
and  electricity  of  these  air  currents  are  different,  as  is  generally 
the  case.     And  seeing  also  that  the  northeast  trade-wind,  as  it 

*  Redfield. 


332       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

draws  more  and  more  toward  the  north,  lies  to  the  left  of  the 
southwest  monsoon,  it  may  be  readily  conceived  why  the  motion 

of  this  whirl  should  be  from  the  right  hand  to  the  left  I     J^,  or 

contrary  to  the  movements  of  the  hands  of  a  watch. 

947.  "Thus,  when  upon  the  limit  of  the  African  monsoon  a  cir- 
cular motion  in  the  air  arises,  we  may  infer,  from  the  situation  of 
the  currents  of  air,  and  their  relation  to  each  other,  that  the  move- 
ment will  be  from  the  right  side  to  the  left.  For  the  same  rea- 
son, the  motion  in  the  southern  hemisphere  in  the  South  Indian 
Ocean  is  from  the  left  hand  to  the  right.  Looking  at  the  north 
pole,  we  find  here  the  currents  of  air  just  the  other  way ;  the  south- 
east and  the  southwest — the  deflected  southeast — are  to  the  left  of 
the  northwest  monsoon.  Therefore,  wdien  a  circular  motion  there 
takes  place  upon  the  limit  of  the  monsoon,  it  must  go  from  the 

left  hand  to  the  right  f    %  or  with  the  hands  of  a  watch. 

948.  "The  want  of  knowledge  prevents  me  from  venturing  to 
penetrate  into  the  '  hidden  chambers  out  of  which  the  whirlwind 
comes,'  for  disturbances  in  the  circulation  of  the  atmosphere  must, 
like  the  revolutions  of  human  society,  bring  all  the  natural  forces 
into  commotion,  and  they,  in  the  strife  which  they  wage,  become 
renewed  and  strengthened  to  perform  their  appointed  work  for  the 
universal  welfare,  and  pass  away  like  the  all-destroying  meteor, 
after  having  accomplished  its  terror-awaking  mission.  The  strife 
— if  indeed  I  may  call  the  opposite  workings  in  nature  strife — is 
violent,  terrible.  The  monsoon  has  attained  its  greatest  strength, 
the  disturbance  in  the  circulation  of  the  atmosphere  has  reached 
its  utmost  limits,  the  vapor  and  the  heavy  clouds  act  in  harmony 
no  longer,  and  with  wild  violence  the  uproar,  nursed  in  silence, 
breaks  forth.  '  The  way  for  the  lightning  of  the  thunder'  appears 
to  be  broken  up. 

949.  "In  the  South  Indian  Ocean  (25°  south  latitude),  a  hur- 
ricane accompanied  by  hail  was  observed,*  by  which  several  of 
the  crew  were  made  blind,  others  had  their  faces  cut  open,  and 
those  who  were  in  the  rigging  had  their  clothes  torn  off  from 

*  The  Rhijin,  Captain  Brandligt. 


STORMS. 


333 


them.  The  master  of  the  ship  compares  the  sea  'to  a  hilly  land- 
scape in  winter,  covered  with  snow.'  Does  it  not  appear  as  if  the 
'  treasures  of  the  hail'  were  opened,  which  were  '  reserved  against 
the  time  of  trouble,  against  the  day  of  battle  and  war  ?'  "* 

950.  ExTRA-TEOPiCAL  Gales. — In  the  extra-tropical  regions 
of  each  hemisphere  furious  gales  of  wind  also  occur.  One  of 
these,  remarkable  for  its  violent  effects,  was  encountered  on  the 
24th  of  December,  1853,  about  three  hundred  miles  from  Sandy 
Hook,  latitude  39 ^  north,  longitude  70°  west,  by  the  San  Francis- 
co, steam-ship  (§  88).  That  ship  was  made  a  complete  wreck  in  a 
few  moments,  and  she  was  abandoned  by  the  survivors,  after  in- 
credible hardships,  exertions,  and  sufferings.  Some  months  after 
this  disaster,  I  received  by  the  California  mail  the  abstract  log  of 
the  fine  clipper  ship  "Eagle  Wing"  (Ebenezer  H.  Linnell),  from 
Boston  to  San  Francisco.  She  encountered  the  ill-fated  steamer's 
gale,  and  thus  describes  it : 

951.  ''December  2Ath,  1853.  Latitude  39°  15^  north,  longi- 
tude 62°  32^  west.  First  part  threatening  weather;  shortened 
sail:  at  4  P.M.  close-reefed  the  top-sails  and  furled  the  courses. 
At  8  P.M.  took  in  fore  and  mizzen  top-sails  ;  hove  to  under  close- 
reefed  main  top-sail  and  spencer,  the  ship  lying  with  her  lee  rail 
under  water,  nearly  on  her  beam-ends.  At  1  30  A.M.  the  fore 
and  main  top-gallant-masts  went  over  the  side,  it  blowing  a  per- 
fect hurricane.  At  8  A.M.,  moderated ;  a  sea  took  away  jib-boom 
and  bowsprit-cap.  In  my  thirty-one  years'  experience  at  sea,  I 
have  never  seen  a  typhoon  or  hurricane  so  severe.  Lost  two  men 
overboard — saved  one.  Stove  sky-light,  broke  my  barometer, 
&c.,  &c." 

952.  Severe  gales  in  this  part  of  the  Atlantic — i.  6.,  on  the  polar 
side  of  the  calm  belt  of  Cancer — rarely  occur  during  the  months 
of  June,  July,  August,  and  September.  This  appears  to  be  the 
time  when  the  fiends  of  the  storm  are  most  busily  at  work  in  the 
West  Indies.  During  the  remainder  of  the  year,  these  extra- 
tropical  gales,  for  the  most  part,  come  from  the  northwest.     But 

*  Natuurkiindige  Beschryving  der  Zeeen,  door  M.  F.  Maury,  LL.D.,  Luitenant  der 
Nord  Araerikaansche  Marine,  vertaald  door  M.  H.  Jansen,  Luitenant  ter  Zee.  Dor- 
drecht, P.  K.  Braat,  1855. 


334  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

the  winter  is  the  most  famous  season  for  these  gales.  That  is  the 
time  when  the  Gulf  Stream  has  brought  the  heat  of  summer  and 
placed  it  (§  84)  in  closest  proximity  to  the  extremest  cold  of  the 
north.  And  there  would  therefore,  it  would  seem,  be  a  conflict 
between  these  extremes ;  consequently,  great  disturbances  in  the 
air,  and  a  violent  rush  from  the  cold  to  the  warm. 

953.  In  like  manner,  the  gales  that  most  prevail  in  the  extra- 
tropics  of  the  southern  hemisphere  come  from  the  pole  and  the 
west,  i.  6.,  southwest. 

954.  Storm  and  Rain  Charts  for  the  Atlantic  Ocean  have  al- 
ready been  published  by  the  Observatory,  and  others  for  the  whole 
seas  are  in  process  of  construction.  The  object  of  such  charts  is 
to  show  the  directions  and  relative  frequency  of  gales  in  all  parts 
of  the  sea,  the  relative  frequency  of  calms,  fogs,  rain,  thunder,  and 
lightning. 

955.  These  charts  are  very  instructive.  They  show  that  that 
half  of  the  atmospherical  coating  of  the  earth  which  covers  the 
northern  hemisphere — if  we  may  take  as  a  type  of  the  whole  what 
occurs  on  either  side  of  the  equator  in  the  Atlantic  Ocean — is  in 
a  much  less  stable  condition  than  that  which  covers  the  southern. 

956.  There  are,  as  a  rule,  more  rains,  more  gales  of  wind,  more 
calms,  more  fogs,  and  more  thunder  and  lightning  in  the  North 
than  in  the  South  Atlantic.  These  phenomena  at  equal  distances 
from  the  equator  north  and  south,  and  for  every  5°  of  latitude, 
have  been  compared  (Plate  XIII.)  ;  that  is,  all  the  storms,  calms, 
rains,  etc.,  between  the  parallels  of  25°  and  30°  N.,  for  instance, 
have  been  compared  with  the  same  between  the  parallels  of  25° 
and  30°  S. ;  those  for  January  north  being  compared  w4th  those 
for  January  south,  and  so  on  for  each  month,  between  all  the  five 
degree  (5°,  10°,  15°,  etc.)  parallels  from  the  equator  to  60°  N. 
and  S. 

957.  In  some  places  here  and  there,  and  in  some  months  now 
and  then,  there  may  be  more  gales,  as  in  the  neighborhood  of  Cape 
Horn,  in  the  South  than  in  the  North  Atlantic ;  but  such  cases 
constitute  the  exceptions — they  are  by  no  means  the  rule.  Cape 
Horn,  in  the  South  Atlantic,  and  the  Gulf  Stream,  in  the  North, 
furnish  seats  for  agents  which  are  very  marked  in  their  workings. 


STORMS.  335 

TMs  Plate  brings  out  the  fact  that,  as  a  rule,  rains  and  calms  go 
together  in  the  tropics  ;  "but  beyond,  rains  and  gales  are  more  apt 
to  occur  at  the  same  time,  or  to  follow  each  other.  With  regard 
to  the  disturbing  agents  which  are  let  loose  iiom  Cape  Horn  and 
the  Gulf  Stream  upon  the  atmosphere,  I  beg  leave  to  quote  a  re- 
mark of  Jansen's : 

958.  "In  contemplating  Xature  in  her  universal  aspect,  in  which 
all  is  so  perfectly  ordered  that  all  the  parts  with  mutual  kindness 
support  each  other  by  the  complaisant  interposition  of  air  and  wa- 
ter, we  can  not  possibly  reject  the  idea  of  unanimity  of  action,  and 
we  may  conjecture  that  when  impeded  or  prevented  by  external 
local  causes,  their  bond  of  union  is  broken,  then  are  observed  the 
terrible  efforts  of  Xature  by  which  its  Almighty  power  is  shown 
in  combating  that  disturbance  of  which  we  know  so  little,  and  in 
renewing  and  perfecting  those  broken  bonds.  Forces  which  are 
otherwise  working  beyond  the  reach  of  human  "s-ision,  then  come 
forth  in  the  combat  for  the  restoration  of  the  disturbed  equilibri- 
um. They  cause  the  earth  to  tremble  to  her  centre,  and  man  to 
stand  anxious  and  dismayed.  Yet  Omniscience  watches,  a  Prov- 
idence cares,  and  the  Almighty  is  love.  The  delightful  land  that 
is  given  us  as  a  dwelling-place,  is  at  the  same  time  the  cause  of 
all  the  disturbances  in  the  air  and  in  the  ocean,  whence  the  hurri- 
canes and  the  "  rivers  in  the  sea*'  arise,  which  in  turn  are  for  the 
universal  good ;  where  they  are  not  found,  we  may  be  certain  that 
the  currents  of  the  air  and  of  the  water  work  undisturbed,  harmo- 
niously together.  And  is  not  this  the  case  in  the  southeast  trade- 
wind  of  the  South  Atlantic  Ocean  f ' 


336  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


CHAPTEE  XYIII. 

ROUTES. 

How  Passages  have  been  shortened,  ^  959. — How  closely  Vessels  follow  each  other's 
Track,  961. — The  Archer  and  the  Flying  Cloud,  962. — The  great  Race-course  upon 
the  Ocean,  964. —  Description  of  a  Ship-race,  966.  —  Present  Knowledge  of  the 
Winds  enables  the  Navigator  to  compute  his  Detour,  991. 

959.  The  principal  routes  across  the  ocean  are  exhibited  on 
Plate  YIII. ;  the  great  end  and  aim  of  all  this  labor  and  research 
are  in  these,  and  consist  in  the  shortening  of  passages — the  im- 
provement of  navigation.  Other  interests  and  other  objects  are 
promoted  thereby,  but  these  last,  in  the  mind  of  a  practical  people, 
who,  by  their  habits  of  thought  and  modes  of  action,  mark  the 
age  in  which  we  live  as  eminently  utilitarian,  do  not  stand  out  in 
relief  half  so  grand  and  imposing  as  do  those  achievements  by 
which  the  distant  isles  and  marts  of  the  sea  have  been  lifted  uj), 
as  it  were,  and  brought  closer  together,  for  the  convenience  of  com- 
merce, by  many  days'  sail. 

960.  We  have  been  told  in  the  foregoing  pages  how  the  winds 
blow  and  the  currents  flow  in  all  parts  of  the  ocean.  These  con- 
trol the  mariner  in  his  course  ;  and  to  know  how  to  steer  his  ship 
on  this  or  that  voyage  so  as  always  to  make  the  most  of  them, 
is  the  perfection  of  navigation.  The  figures  representing  the  ves- 
sels are  so  marked  as  to  show  whether  the  prevailing  direction  of 
the  wind  be  adverse  or  fair. 

961.  When  one  looks  seaward  from  the  shore,  and  sees  a  ship 
disappear  in  the  horizon  as  she  gains  an  offing  on  a  voyage  to  In- 
dia, or  the  Antipodes  j^erhaps,  the  common  idea  is  that  she  is 
bound  over  a  trackless  waste,  and  the  chances  of  another  ship, 
sailing  with  the  same  destination  the  next  day,  or  the  next  week, 
coming  up  and  speaking  with  her  on  the  "  pathless  ocean,"  would, 
to  most  minds,  seem  slender  indeed.  Yet  the  truth  is,  the  winds 
and  the  currents  are  now  becomino-  to  be  so  well  understood,  that 


the  navigator,  like  the  backwoodsman  in  the  wilderness,  is  enabled 


ROUTES. 


337 


literally  "to  blaze  his  way"  across  the  ocean;  not,  indeed,  upon 
trees,  as  in  the  wilderness,  but  upon  the  wings  of  the  wind.  The 
results  of  scientific  inquiry  have  so  taught  him  how  to  use  these 
invisible  couriers,  that  they,  with  the  calm  belts  of  the  air,  serve 
as  sign-boards  to  indicate  to  him  the  turnings,  and  forks,  and  cross- 
ings by  the  way. 

962.  Let  a  ship  sail  from  J^Tew  York  to  California,  and  the  next 
w^eek  let  a  faster  one  follow  after:  they  will  cross  each  other's 
path  many  times,  and  are  almost  sure  to  see  each  other  by  the 
way.  Thus  a  case  in  point  happens  to  be  before  me.  It  is  the 
case  of  the  "xircher"  and  the  "  Flying  Cloud"  on  a  recent  voy- 
age to  California.  They  are  both  fine  clipper  ships,  ably  com- 
manded. But  it  was  not  until  the  ninth  day  after  the  "Archer" 
had  sailed  from  New  York  that  the  "  Flying  Cloud"  put  to  sea, 
California-bound  also.  She  was  running  against  time,  and  so  was 
the  ' '  Archer, "  but  without  reference  to  each  other.  The  ' '  Archer, " 
with  "Wind  and  Current  Charts"  in  hand,  went  blazing  her  way 
across  the  calms  of  Cancer,  and  along  the  new  route,  down  through 
the  northeast  trades  to  the  equator  ;  the  "  Cloud"  followed  after, 
crossing  the  equator  upon  the  trail  of  Thomas  of  the  "Archer." 
Off  Cape  Horn  she  came  up  with  him,  spoke  him,  handed  hini 
the  latest  New  York  dates,  and  invited  him  to  dine  on  board  the 
"  Cloud,"  which  invitation,  says  he  of  the  "Archer,"  "  I  was  re- 
luctantly compelled  to  decline." 

963.  The  "Flying  Cloud"  finally  ranged  ahead,  made  her  adieus, 
and  disappeared  among  the  clouds  that  lowered  upon  the  western 
horizon,  being  destined  to  reach  her  port  a  week  or  more  in  ad- 
vance of  her  Cape  Horn  consort.  Though  sighting  no  land  from 
the  time  of  their  separation  until  they  gained  the  offing  of  San 
Francisco — some  six  or  eight  thousand  miles  off — the  tracks  of 
the  two  vessels  were  so  nearly  the  same,  that,  being  projected  on 
the  Plate  IX.,  they  would  appear  almost  as  one. 

964.  This  is  the  great  race-course  of  the  ocean ;  it  is  fifteen 
thousand  miles  in  length.  Some  of  the  most  glorious  trials  of 
speed  and  of  prowess  that  the  world  ever  witnessed,  among  ships 
that  "walk  the  waters,"  have  taken  place  over  it.  Here  the  mod- 
ern clipper  ship — the  noblest  work  that  has  ever  come  from  the 


338  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

hands  of  man — lias  been  sent,  guided  by  the  lights  of  science,  to 
contend  with  the  elements,  to  outstrip  steam,  and  astonish  the 
world. 

9G5.  The  most  celebrJited  and  famous  ship-race  that  has  ever 
been  run  came  off  upon  this  course :  it  was  in  the  autumn  of  1852, 
when  navigators  were  beginning  fully  to  reap  the  benefits  of  these 
researches  with  regard  to  the  winds  and  currents,  and  other  facts 
connected  with  the  Physical  Geography  of  the  Sea,  that  four 
splendid  new  clipper  ships  put  to  sea  from  New  York,  bound  for 
California.  They  were  ably  commanded,  and,  as  they  passed  the 
bar  at  Sandy  Hook,  one  by  one,  and  at  various  intervals  of  time, 
they  presented  really  a  most  magnificent  spectacle.  The  names 
of  these  noble  ships  and  their  masters  were,  the  "Wild  Pigeon," 
Captain  Putnam  ;  the  "John  Gilpin,"  Captain  Doane — alas  !  now 
no  more;  the  "Flying  Fish,"  Captain  Nickels,  and  the  "Trade 
Wind,"  Captain  Webber.  Like  steeds  that  know  their  riders, 
they  were  handled  with  the  most  exquisite  skill  and  judgment, 
and  in  such  hands  they  bounded  out  upon  the  "  glad  waters"  most 
gracefully.  Each,  being  put  upon  her  mettle  from  the  start,  was 
driven,  under  the  seaman's  whip  and  spur,  at  full  speed  over  a 
course  that  it  would  take  them  three  long  months  to  run. 

966.  The  "Wild  Pigeon"  sailed  October  12;  the  "  John  Gil- 
pin,"  October  29 ;  the  "  Flying  Fish,"  November  1  ;  and  the 
"  Trade  Wind,"  November  14.  It  was  the  season  for  the  best 
passages.  Each  one  was  provided  with  the  Wind  and  Current 
Charts,  Each  one  had  evidently  studied  them  attentively ;  and 
each  one  was  resolved  to  make  the  most  of  them,  and  do  his  best. 
All  ran  against  time ;  but  the  "John  Gilpin"  and  the  "Flying  Fish" 
for  the  whole  course,  and  the  "Wild  Pigeon"  for  part  of  it,  ran 
neck  and  neck,  the  one  against  the  other,  and  each  against  all.  It 
was  a  sweepstake  with  these  ships  around  Cape  Horn  and  through 
both  hemispheres. 

967.  Wild  Pigeon  led  the  other  two  out  of  New  York,  the  one 
by  seventeen,  the  other  by  twenty  days.  But  luck  and  chances  of 
the  winds  seem  to  have  been  against  her  from  the  start.  As  soon 
as  she  had  taken  her  departure,  she  fell  into  a  streak  of  bafiling 
winds,  and  then  into  a  gale,  which  she  fought  against  and  con- 


ROUTES.  339 

tended  with  for  a  -week,  making  but  little  progress  the  while ;  she 
then  had  a  time  of  it  in  crossing  the  horse  latitudes.  After  hav- 
ing been  nineteen  days  out,  she  had  logged  no  less  than  thirteen 
of  them  as  days  of  calms  and  baffing  winds  ;  these  had  brought 
her  no  farther  on  her  way  than  the  parallel  of  26°  north  in  the  At- 
lantic. Thence  she  had  a  fine  run  to  the  equator,  crossing  it  be- 
tween 33°  and  34°  west,  the  thirty-second  day  out.  She  was  un- 
avoidably forced  to  cross  it  so  far  west ;  for  only  two  days  before, 
she  crossed  5°  north  in  30° — an  excellent  position. 

968.  In  proof  that  the  Pigeon  had  accomplished  all  that  skill 
could  do  and  the  chances  against  her  would  permit,  we  have  the 
testimony  of  the  barque  Hazard,  Captain  Pollard.  This  vessel, 
being  bound  to  E,io  at  the  same  time,  followed  close  after  the 
Pigeon.  The  Hazard  is  an  old  hand  with  the  Charts ;  she  had 
already  made  six  voyages  to  Rio  with  them  for  her  guide.  This 
was  the  longest  of  the  six,  the  mean  of  which  was  twenty-six  and 
a  half  days.  She  crossed  the  line  this  time  in  34°  39^,  also  by 
compulsion,  having  crossed  5°  north  in  31°.  But,  the  fourth  day 
after  crossing  the  equator,  she  was  clear  of  Cape  St.  Eoque,  while 
the  Pigeon  cleared  it  in  tliree  days.* 

969.  So  far,  therefore,  chances  had  turned  up  against  the  Pig-. 
eon,  in  spite  of  the  skill  displayed  by  Putnam  as  a  navigator,  for 
the  Gilpin  and  the  Fish  came  booming  along,  not  under  better 
management,  indeed,  but  with  a  better  run  of  luck  and  fairer 
courses  before  them.  In  this  stretch  they  gained  upon  her — the 
Gilpin  seven  and  the  Fish'  ten  days ;  so  that  now  the  abstract 
logs  show  the  Pigeon  to  be  but  ten  days  ahead. 

970.  Evidently  the  Fish  was  most  confident  that  she  had  the 
heels  of  her  competitors  ;  she  felt  her  strength,  and  was  proud  of 
it ;  she  was  most  anxious  for  a  quick  run,  and  eager  withal  for  a 
trial.  She  dashed  down  southwardly  from  Sandy  Hook,  looking 
occasionally  at  the  Charts ;  but  feeling  strong  in  her  sweep  of 
wing,  and  trusting  confidently  in  the  judgment  of  her  master,  she 
kept,  on  the  average,  two  hundred  miles  to  leeward  of  the  right 
track.  Rejoicing  in  her  many  noble  and  fine  qualities,  she  crowd- 
ed on  her  canvas  to  its  utmost  stretch,  trusting  quite  as  much  to 

*  According  to  the  received  opinion,  this  was  impossible.      Vide  ^  470. 

Y 


340  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

lier  heels  as  to  the  Cliarts,  and  performed  the  extraordinary  feat 
of  crossing,  the  sixteenth  day  out  from  New  York,  the  parallel  of 

5°  north. 

971.  The  next  day  she  was  well  south  of  4°  north,  and  in  the 
Doldrums,  longitude  34°  west. 

Now  her  heels  became  paralyzed,  for  Fortune  seems  to  have  de- 
serted her  a  while — at  least  her  master,  as  the  winds  failed  him, 
feared  so  ;  they  gave  him  his  motive  power  ;  they  were  fickle,  and 
he  was  helplessly  baffled  by  them.  The  bugbear  of  a  northwest 
current  off  Cape  St.  Roque  (§  470)  began  to  loom  up  in  his  im- 
agination, and  to  look  alarming ;  then  the  dread  of  falling  to  lee- 
ward came  upon  him  ;  chances  and  luck  seemed  to  conspire  against 
him,  and  the  mere  possibility  of  finding  his  fine  ship  back-strapped 
filled  the  mind  of  Nickels  with  evil  forebodings,  and  shook  his 
faith  in  his  guide.  He  doubted  the  Charts,  and  committed  the 
mistake  of  the  passage. 

972.  The  Sailing  Directions  had  cautioned  the  navigator,  again 
and  again,  not  to  attempt  to  fan  along  to  the  eastward  in  the  equa- 
torial doldrums;  for,  by  so  doing,  he  would  himself  engage  in  a 
fruitless  strife  with  baffling  airs,  sometimes  re-enforced  in  their 
weakness  by  westerly  currents.  But  the  winds  had  failed,  and  so 
too,  the  smart  captain  of  the  Flying  Fish  evidently  thought,  had 
the  Sailing  Directions.  They  advise  the  navigator,  in  all  such 
cases,  to  dash  right  across  this  calm  streak,  stand  boldly  on,  take 
advantage  of  slants  in  the  wind,  and,  by  this  device,  make  easting 
enough  to  clear  the  land.  So,  forgetting  that  the  Charts  are 
founded  on  the  experience  of  great  numbers  who  had  gone  before 
him.  Nickels,  being  te'mpted,  turned  a  deaf  ear  to  the  caution,  and 
flung  away  three  whole  days,  and  more,  of  most  precious  time, 
dallying  in  the  doldrums. 

He  spent  four  days  about  the  parallel  of  3°  north,  and  his  ship 
left  the  doldrums,  after  this  waste  of  time,  nearly  upon  the  same 
meridian,  at  which  she  entered  them. 

973.  She  was  still  in  34^^,  the  current  keeping  her  back  just  as 
fast  as  she  could  fan  east.  After  so  great  a  loss,  her  very  clever 
master,  doubting  his  own  judgment,  became  sensible  of  his  error. 
Leaving  the  spell-bound  calms  behind  him,  where  he  had  under- 


ROUTES.  341 

gone  such  trials,  lie  wrote  in  his  log  as  follows:  "I  now  regret 
that,  after  making  so  fine  a  run  to  5°  north,  I  did  not  dash  on,  and 
work  my  way  to  windward  to  the  northward  of  St.  Roqiie,  as  I 
have  experienced  little  or  no  westerly  set  since  passing  the  equa- 
tor, while  three  or  four  days  have  been  lost  in  working  to  the  east- 
ward, between  the  latitude  of  5°  and  3°  north,  against  a  strong 
westerly  set ;"  and  he  might  have  added,  "  with  little  or  no  wind." 

974.  In  three  days  after  this  he  was  clear  of  St.  Roque.  Just 
five  days  before  him,  the  Hazard  had  passed  exactly  in  the  same 
place,  and  gained  two  days  on  the  Fish  by  cutting  straight  across 
the  doldrums,  as  the  Sailing  Directions  advised  him  to  do. 

975.  The  AYild  Pigeon,  crossing  the  equator  also  in  33°,  had 
passed  along  there  ten  days  before,  as  did  also  the  Trade  Wind 
twelve  days  after.  The  latter  also  crossed  the  line  to  the  west  of 
34*^,  and  in  4  days  after  had  cleared  St.  Eoque. 

976.  But,  notwithstanding  this  loss  of  three  days  by  the  Fish, 
who  so  regretted  it,  and  who  afterward  so  handsomely  retrieved 
it,  she  found  herself,  on  the  24th  of  November,  alongside  of  the 
Gilpin,  her  competitor.  They  were  then  both  on  the  parallel  of 
5°  south,  the  Gilpin  being  thirty-seven  miles  to  the  eastward,  and 
of  course  in  a  better  position,  for  the  Fish  had  yet  to  take  advant- 
age of  slants,  and  stand  off  shore  to  clear  the  land.  They  had 
not  seen  each  other. 

977.  The  Charts  showed  the  Gilpin  now  to  be  in  the  best  po- 
sition, and  the  subsequent  events  proved  the  Charts  to  be  right, 
for  thence  to  53°  south  the  Gilpin  gained  on  the  Pigeon  two  days, 
and  the  Pigeon  on  the  Fish  one. 

978.  By  dashing  through  the  Straits  of  Le  Maire,  the  Fish 
gained  three  days  on  the  Gilpin ;  but  here  Fortune  again  desert- 
ed the  Pigeon,  or  rather  the  windg  turned  against  her ;  for  as  she 
appeared  upon  the  parallel  of  Cape  Horn,  and  was  about  to  double 
round,  a  westerly  gale  struck  her  "in  the  teeth,"  and  kept  her  at 
bay  for  ten  days,  making  little  or  no  way,  except  alternately  fight- 
ing in  a  calm  or  buffeting  with  a  gale,  while  her  pursuers  were 
coming  up  "hand  over  fist,"  with  fine  winds  and  flowing  sheets. 

979.  They  finally  overtook  her,  bringing  along  with  them  pro- 
pitious gales,  when  all  three  swept  past  the  Cape,  and  crossed  the 


342        THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

parallel  of  51°  south  on  the  other  side  of  the  "Horn,"  the  Fish 
and  the  Pigeon  one  day  each  ahead  of  the  Gilpin. 

The  Pigeon  was  now,  according  to  the  Charts,  in  the  Lest  po- 
sition, the  Gilpin  next,  and  the  Fish  last ;  hut  all  were  doing  well. 

980.  From  this  parallel  to  the  southeast  trades  of  the  Pacific 
the  prevailing  winds  are  from  the  northwest.  The  position  of  the 
Fish,  therefore,  did  not  seem  as  good  as  the  others,  because  she 
did  not  have  the  sea-room  in  case  of  an  obstinate  northwest  gale. 

981.  But  the  winds  favored  her.  On  the  oOtli  of  December 
the  three  ships  crossed  the  parallel  of  35°  south,  the  Fish  recog- 
nizing the  Pigeon ;  the  Pigeon  saw  only  a  "  clipper  ship,"  for  she 
could  not  conceive  how  the  ship  in  sight  could  possibly  be  the 
Flying  Fish,  as  that  vessel  was  not  to  leave  New  York  for  some 
three  weeks  after  she  did ;  the  Gilpin  was  only  thirty  or  forty 
miles  off  at  the  same  time. 

982.  The  race  was  now  wing  and  wing,  and  had  become  excit- 
ing. With  fair  winds  and  an  open  sea,  the  competitors  had  now 
a  clear  stretch  to  the  equator  of  two  thousand  five  hundred  miles 
before  them. 

983.  The  Flying  Fish  led  the  way,  the  Wild  Pigeon  pressing 
her  hard,  and  both  dropping  the  Gilpin  quite  rapidly,  who  was 
edging  off  to  the  westward. 

The  two  foremost  reached  the  equator  on  the  13th  of  January, 
the  Fish  leading  just  twenty-five  miles  in  latitude,  and  crossing  in 
11.2°  17^;*  the  Pigeon  forty  miles  farther  to  the  east.  At  this 
time  the  John  Gilpin  had  dropped  two  hundred  and  sixty  miles 
astern,  and  had  sagged  off  several  degrees  to  the  westward. 

984.  Here  Putnam,  of  the  Pigeon,  again  displayed  his  tact  as 
a  navigator,  and  again  the  fickle  winds  deceived  him :  the  belt  of 
northeast  trades  had  yet  to  be  passed ;  it  was  winter ;  and,  by 
crossing  where  she  did,  she  would  have  an  opportunity  of  making 
a  fair  wind  of  them,  without  being  much  to  the  west  of  her  port 
when  she  should  lose  them.  ]\Ioreover,  it  was  exactly  one  year 
since  she  had  passed  this  way  before ;  she  then  crossed  in  109°, 
and  had  a  capital  run  thence  of  seventeen  days  to  San  Francisco. 

*  Twenty-five  days  after  that,  the  Trade  Wind  cUpper  came  along,  crossed  in  112°, 
and  had  a  passage  of  sixteen  days  thence  into  San  Francisco. 


V 


ROUTES.  m  343 

985.  Why  sliould  slic  not  cross  here  again  ?  She  saw  that  the 
4th  edition  of  Sailing  Directions,  which  she  had  on  board,  did 
not  discountenance  it,  and  her  own  experience  approved  it.  Could 
she  have  imagined  that,  in  consequence  of  this  difference  of  forty 
miles  in  the  crossing  of  the  equator,  and  of  the  two  hours'  time 
behind  her  competitor,  she  would  fall  into  a  streak  of  wind  which 
would  enable  the  Fish  to  lead  her  into  port  one  whole  week  ? 
Certainly  it  was  nothing  but  what  sailors  call  "a  streak  of  ill 
luck"  that  could  have  made  such  a  difference. 

986.  But  by  this  time  "John  Gilpin"  had  got  his  mettle  up 
again.  He  crossed  the  line  in  116° — exactly  two  days  after  the 
other  two — and  made  the  glorious  run  of  fifteen  days  thence  to 
the  pilot  grounds  of  San  Francisco. 

Thus  end  the  abstract  logs  of  this  exciting  race  and  these  re- 
markable passages. 

987.  The  Flying  Fish  beat :  she  made  the  passage  in  92  days 
and  4  hours  from  port  to  anchor ;  the  Gilpin  in  93  days  and  20 
hours  from  port  to  pilot  ;*  the  Wild  Pigeon  had  118.  The  Trade 
Wind  followed,  with  102  days,  having  taken  fire,  and  burned  for 
eight  hours  on  the  way. 

988.  The  result  of  this  race  may  be  taken  as  an  illustration  as. 
to  how  well  navigators  are  now  brought  to  understand  the  winds 
and  the  currents  of  the  sea. 

989.  Here  are  three  ships  sailing  on  different  days,  bound  over 
a  trackless  waste  of  ocean  for  some  fifteen  thousand  miles  or  more, 
and  depending  alone  on  the  fickle  winds  of  heaven,  as  they  are 
called,  to  waft  them  along ;  yet,  like  travelers  on  the  land,  bound 
upon  the  same  journey,  they  pass  and  repass,  fall  in  with  and  rec- 
ognize each  other  by  the  way ;  and  what,  perhaps,  is  still  more  re- 
markable, is  the  fact  that  these  ships  should  each,  throughout  that 
great  distance,  and  under  the  wonderful  vicissitudes  of  climates, 
winds,  and  currents  which  they  encountered,  have  been  so  skill- 
fully navigated,  that,  in  looking  back  at  their  management,  now 
that  what  is  past  is  before  me,  I  do  not  find  a  single  occasion,  ex- 
cept the  one  already  mentioned,  on  which  they  could  have  been 
better  handled. 

*  The  abstract  log  of  the  Gilpin  is  silent  after  the  pilot  came  on  board. 


344  THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

990.  There  is  anotlier  circumstance  wliicli  is  worthy  of  notice 
in  this  connection,  as  ilkistrative  of  the  accuracy  of  the  knowledge 
which  these  investigations  afford  concerning  the  force,  set,  and  di- 
rection both  of  winds  and  currents,  and  it  is  this : 

991.  I  had  computed  the  detour  which  these  vessels  would 
have  to  make,  on  account  of  adverse  winds,  between  New  York 
and  their  place  of  crossing  the  equator.  The  whole  distance,  in- 
cluding detour,  to  be  sailed  to  reach  this  crossing  at  that  season 
of  the  year,  was,  according  to  calculation,  4115  miles.  The  "Gil- 
pin" and  the  "  Hazard''  only  kept  an  account  of  the  distance  act- 
ually sailed ;  the  former  reaching  -the  equator  after  sailing  4099 
miles,  the  latter  4077  ;  thus  accomplishing  that  part  of  the  voy- 
age by  sailing,  the  one  within  thirty-eight,  the  other  within  six- 
teen miles  of  the  detour  which  calculation  showed  they  would  be 
compelled  to  make  on  account  of  head-winds.  With  his  way 
blazed  through  the  forest,  the  most  experienced  backwoodsman 
would  have  to  make  a  detour  greater  than  this  on  account  of 
floods  in  the  rivers.  Am  I  far  wrong,  therefore,  when  I  say  that 
the  present  state  of  our  knowledge  with  regard  to  the  physical 
geography  of  the  sea  has  enabled  the  navigator  to  blaze  his  way 
among  the  winds  and  currents  of  the  sea,  and  so  mark  his  path 
that  others,  using  his  signs  as  finger-boards,  may  follow  in  the 
same  track  ? 


A  LAST  WORD.  345 


CHaPTEE  XIX. 

A   LAST   WORD. 

Brussels  Conference,  ^  996. — How  Navigators  may  obtain  a  Set  of  the  Maury  Charts, 

997.— The  Abstract  Log,  998. 

992.  I  HAVE,  I  am  aware,  not  done  more  in  this  little  Look  than 
given  only  a  table  or  two  of  contents  from  the  interesting  volume 
which  the  Physical  Geography  of  the  Sea  is  destined  some  day 
to  open  up  to  us.  The  subject  is  a  comprehensive  one :  there  is 
room  for  more  laborers,  and  help  is  wanted. 

Nations,  no  less  than  individuals  ;  "  stay-at-home  travelers,"  as 
well  as  those  who  "go  down  to  the  sea  in  ships,"  are  concerned 
in  the  successful  prosecution  of  the  labors  we  have  in  hand. 

We  are  now  about  to  turn  over  a  new  leaf  in  navigation,  on 
which  we  may  confidently  expect  to  see  recorded  much  informa- 
tion that  will  tend  to  lessen  the  dangers  of  the  sea,  and  to  short- 
en the  passages  of  vessels  trading  upon  it. 

993.  We  are  about  to  open  in  the  volume  of  Nature  a  new  chap- 
ter, under  the  head  of  Marine  Meteorology.  In  it  are  written 
the  laws  that  govern  those  agents  which  "the  winds  and  the  sea 
obey."  In  the  true  interpretation  of  these  laws,  and  the  correct 
reading  of  this  chapter,  the  planter  as  well  as  the  merchant,  the 
husbandman  as  well  as  the  mariner,  and  states  as  well  as  indi- 
viduals, are  concerned.  All  have  a  deep  interest  in  these  laws ; 
for  with  the  hygrometrical  conditions  of  the  atmosphere,  the  well- 
being  of  plants  and  animals  is  involved.  The  health  of  the  invalid 
is  often  dependent  upon  a  dry  or  a  damp  atmosphere,  a  cold  blast 
or  a  warm  wind. 

994.  The  atmosphere  pumps  up  our  rivers  from  the  sea,  and 
transports  them  through  the  clouds  to  their  sources  among  the 
hills  ;  and  upon  the  regularity  with  which  this  machine,  whose 
motions,  parts,  and  offices  we  now  wish  to  study,  lets  down  that 
moisture,  and  the  seasonable  supply  of  rain  which  it  furnishes  to 


346       THE  PHYSICAL  GEOGRAPHY  OF  THE  SEA. 

each  region  of  country,  to  every  planter,  and  upon  all  cultivated 
fields,  depend  the  fruitfulness  of  this  country,  the  sterility  of  that. 

995.  The  principal  maritime  nations,  therefore,  have  done  well 
by  ao-reeing  to  unite  upon  one  plan  of  observation,  and  to  co-op- 
erate with  their  ships  upon  the  high  seas  with  the  view  of  finding 
out  all  that  patient  research,  systematic,  laborious  investigation, 
may  reveal  to  us  concerning  the  winds  and  the  waves  ;  and  phil- 
osophical travelers,  and  every  sailor  that  has  a  ship  under  his  foot, 
may  do  even  better  by  joining  in  this  system. 

996.  By  the  recommendations  of  the  Brussels  Conference,  ev- 
ery one  who  uses  the  sea  is  commanded  or  invited  to  make  cer- 
tain observations  ;  or,  in  other  words,  to  propound  certain  queries 
to  Nature,  and  to  give  us  a  faithful  statement  of  the  replies  she 
may  make. 

Now,  unless  we  have  accurate  instruments,  instruments  that 
will  themselves  tell  the  truth,  it  is  evident  that  we  can  not  get  at 
the  real  meaning  of  the  answers  that  Nature  may  give  us. 

An  incorrect  observation  is  not  only  useless  of  itself,  but,  when 
it  passes  undetected  among  others  that  are  correct,  it  becomes 
worse  than  useless  ;  nay,  it  is  mischievous  there,  for  it  vitiates  re- 
sults that  are  accurate,  places  before  us  wrong  premises,  and  thus 
renders  the  good  of  no  value. 

997.  Those  ship-masters,  who,  entering  this  field  as  fellow-la- 
borers, will  co-operate  in  the  mode  and  manner  recommended  by 
the  Brussels  Conference,  and  keep,  voyage  after  voyage,  and  as 
long  as  required,  a  journal  of  observations  and  results  according 
to  a  prescribed  form — and  which  form  is  annexed,  under  the  title 
of  Abstract  Log — are  entitled,  by  sending  the  same,  at  the  end  of 
the  voyage,  to  the  Superintendent  of  the  National  Observatory,  to 
a  copy  of  my  Sailing  Directions,  and  such  sheets  of  the  Charts  as 
relate  to  the  cruising-ground  of  the  co-operator. 

998.  There  are  two  forms  of  abstract  logs  :  one,  the  more  elab- 
orate, for  men-of-war ;  the  other  for  merchantmen.  The  observa- 
tions called  for  by  the  latter  are  a  minimmn,  the  least  which  will 
entitle  the  co-operator  to  claim  the  proffered  bounty.  It  must  give, 
at  leasts  the  latitude  and  longitude  of  the  ship  daily ;  the  height 
of  the  barometer,  and  the  readings  of  both  the  air  and  the  water 


A  LAST  WORD.  347 

thermometer,  at  least  once  a  day ;  the  direction  and  force  of  the 
wind  three  times  a  day — first,  middle,  and  latter  part — at  the  hours 
eight  P.M.,  four  A.M.,  and  noon ;  the  variation  of  the  compass 
occasionally ;  and  the  set  of  the  current  whenever  encountered. 
These  observations,  to  be  worth  having,  must  be  accurately  made  ; 
and  as  every  thermometer  and  every  barometer  has  its  sources  of 
error,  consequently,  every  ship-master  who  undertakes  hereafter  to 
co-operate  with  us,  and  keep  an  abstract  log,  should  have  his  ba- 
rometer and  thermometer  accurately  compared  with  standard  in- 
struments, the  errors  of  which  have  been  accurately  determined. 

999.  These  errors  the  master  should  enter  in  the  log ;  the  in- 
struments should  be  numbered,  and  he  should  so  keep  the  log  as 
to  show  what  instrument  is  in  use.  For  instance,  a  master  goes 
to  sea  with  thermometers  Nos.  4719,  1, 12,  etc.,  their  errors  hav- 
ing been  ascertained  and  entered  on  the  blank  page  for  the  pur- 
pose in  the  abstract  log.  He  first  uses  jSTo.  12.  Let  it  be  so  stated 
in  the  column  of  Remarks,  when  the  first  observation  is  recorded, 
thus  :  Thermometer  No.  12.  During  the  voyage,  No.  12  gets  bro- 
ken, or  for  some  reason  is  laid  aside,  and  another,  say  4719,  is 
brought  into  use.  So  state  when  the  first  observation  with  it  is 
recorded,  and  quote  in  the  column  of  Eemarks  the  errors  both  of 
Nos.  12  and  4719.  Now,  with  such  a  statement  of  errors  given  in 
the  log  for  each  of  the  instruments,  according  to  the  number,  the 
observations  may  be  properly  corrected  when  they  come  up  here 
for  discussion. 

1000.  It  is  rare  to  find  a  barometer  or  a  thermometer  that  has 
no  error,  as  it  is  to  find  a  chronometer  without  error.  A  good 
thermometer,  the  error  of  which  the  maker  should  guarantee  not  to 
exceed  in  any  part  of  the  scale  one  degree,  will  cost,  in  the  United 
States,  not  less  than  $2,  perhaps  $2  50. 

1001.  The  errors  of  thermometers  sometimes  are  owino-  to  in- 
equalities  in  the  bore  of  the  tube,  sometimes  to  errors  of  di\^sion 
on  the  scale,  etc.  Therefore,  in  comparing  thermometers  with  a 
standard,  they  should  be  compared,  at  least,  for  every  degree  be- 
tween melting  ice  and  blood  heat. 


348 


PHYSICAL  GEOGRAPHY  OF  THE  SEA. 


00 


fcjo 


^ 


CO  ! 

r— I 

5^ 


I 

H-5 


fill 


O  O  'S  !^    £    " 


p  cd  £  .^  ( 


'<^ 


^  V  f-i   -    I    M 
"         •  ■  -  w  o 

<^.zi.o  5-- 

^  ^-  I    o  ^  "^ 

,-v  C     '.    (_  f>  30 

iS  o  m  p_,  ,.,    ^ 
Y  -^    ■       fcr,  M 

5.7^00  .£f^ 


-if  ^ 


>"    rj  t.-  '^  C3 
e!  S   O   C   c3 


C  K 


r'O 


S  o 


■5  ^  «   ?-~-.i3 
tS   u   ^   J-;   -2  ■" 


Sfe  CS! 


cj  ad  — ,   I  «—  ja" 
'1  -2  =^  £  S  "^ 

Q  >  C  .o  - 


■« 

r/i 

o 

S 

35 

Si 

;? 

T 

-- 

a 

in 

00 

C2< 

tj 

m 

,^ 

i=! 

s 

1 

o 

1 

OH 

'^ 

>^ 

1 

ro 

,^ 

^^. 

in 

a 

S^ 

ce 

2- 

u 

r- 

3 

1 

a 

.r: 

tc 

F-> 

>-, 

o 

CO 

r' 

?: 

o 

Q  1? 

>. 

r-.^ 

o 

c 

1-5 

1 

■^ 

w 

f^ 

^ 

V 

-o 

O 

1 

•' 

bX) 

o 

1 

w 

0 

•T3 

> 

PS 

w 

■5 

0 

«- 

r 

0) 

en 

W 

p; 

tn 

cq 

Pi 

o 

o 

-t- 

•« 

a 

c 

s 

«i 

(M 

« 

^ 

c 

>" 

ec  ■*■ 

^ 

b£ 

1 

tf 

.^ 

t-l 

t^ 

CO 

V^ 


^ 


pq  H-H 


£    S 


£   -I 


> 


in 

C30 

C3  —    „ 

.M.,  from 
severally 
umns  12', 

^-■=»-2 

f-^-oo 

,.-^H 

00   £   " 

tj  CO  cs 

^"^ 

2|<2 

C  a.'  C 
?  ai.2 

bi)^  -(I 

rt.'S 

C     .  cJ 

0  -o  2 

from 
must 
iserv 
P.M. 

Oi  ,  -  0 

■"  Cl  •— 

0 

'A 

< 

pond  with 
',  13',  14', 
umbers  in 
tcr. 

f  the  wind 
.  till  noon 
d  noon,     f 
A.M.  und 

1:3 

orres 

6',  12 
me  n 
),  wa 

ion  0 
A  M 
4,  an 
at  9 

0 

iling  direct 
and  from  '-. 
opposite  8, 
ad  17',  also 

c^ 

^<u  ^  *1  ^ 

..^  -  IB  ,-C 

"<i  5~'  •S  'J* 

«    r  to  c3 

Si  —  ai 

be— <  «J 

>~     .  -  0 

-S  -^  S  •: 

S'"=^'" 

■^  c-^  c 

2^  P^" 

Eh   0   S(N 

he 
lun 
hei 
1.5 

Qi     0    *J 

H  <D  .-li  0 

Ui*)    *^  ^  - 

^^-^ 

C  M 
00   0  -1 

^ 

1 

1 

1 

^3 

'-' 

11 

i 

1 

n          t 

0 

1 

'— 

I 

i 

^ 

OJ 

^ 

B 

n 

0 

CO 

1 

^ 

0 

1— 1 

0 

h-1 

0 

r— 1 

0 

' 

0 

;> 

■-. 

^ 

w 

CO 

H 

CO 

;z; 

^ 

<1 

'^ 

w 

0 

p^ 

w 

^ 

s 

t^ 

10 

^ 

fct 

CO 

^ 

— ; 

^ 

M.J 

CI 

0 

—^ 

CO 

' 

r* 

C5 

— 1 

w 

y. 

> 

rXl 

.c: 

60 

,M 

r" 

-<j 

^ 

"X 

-^ 

1— ( 

cs 

0 

-3 

c 

',< 

^ 

ADDENDA. 


Page  147,  ^  394. 

ScHONBEiN,  a  few  years  ago,  discovered  ozone  in  tlie  atmos- 
pliere,  and  since  that,  thougli  chemists  are  not  agreed  as  to  what 
this  new  substance  is — if  it  be  a  new  substance — or  how,  or  where, 
in  the  laboratories  of  nature,  it  is  generated,  it  has  been  used  by 
meteorologists  as  an  implement  or  means  for  carrying  on  their 
observations. 

The  indefatigable  Dr.  Pegado,  in  his  capacity  as  Director  of  the 
Meteorological  Observatory  of  the  Polytechnic  School  of  Portugal, 
has  introduced  into  his  meteorological  journal  a  column  for  reg- 
ular ozonometrical  observations.  He  has  the  usual  scale  of  colors, 
and  makes  two  observations  a  day.  In  order  to  make  an  obser- 
vation, the  ozone  paper  is  exposed  to  the  air  for  12  hours,  and 
then,  according  to  the  depth  of  the  color  which  the  paper  has  as- 
sumed, the  relative  abundance  of  ozone  is  judged  of. 

The  doctor  commenced  these  observations  in  July,  1855  ;  and, 
according  to  the  meteorological  annals  of  the  Polytechnic  School 
from  July  to  November  of  that  year,  the  quantity  of  ozone  in  the 
atmosphere  appears  to  be  directly  as  the  moisture,  and  inversely 
as  the  pressure,  without  regard  to  the  direction  of  the  winds. 

In  Massachusetts,  according  to  the  observations  of  Professor 
W.  B.  Eogers  for  six  weeks  in  winter,*  ozone  is  most  abundant  in 
northwestwardly  winds ;  least  so  in  winds  having  southing  or 
easting  in  them. 

My  friend  Jansen,  of  the  Dutch  Navy,  made  a  series  of  obser- 
vations with  ozone  paper  all  the  way  from  England  to  Australia. 
He  was  on  board  the  "  Royal  Charter"  in  the  spring  of  1856, 
when  she  made  the  unprecedented  run  of  59|  days  to  Australia. 
His  observations  were  made  on  board  that  vessel,  and,  in  giving 
me  an  account  of  the  voyage  on  his  arrival  at  Melbourne,  he  says : 

"  I  forgot  to  mention  my  observations  with  ozone  paper.    They 

*  See  Transactions  Soc.  Nat.  History  of  Boston,  v.  319. 


350  ADDENDA. 

have  been  very  interesting.  I  found,  as  far  as  I  could  make  de- 
ductions from  a  single  set  of  carefully-made  observations,  that  the 
ozone  is  manufactured  between  the  tropics.  I  invariably  found 
the  ozone  most  abundant  in  the  winds  that  blow  north  and  south 
of  the  trades  from  the  equator.  In  the  winds  from  the  pole  there 
was  but  little  ozone." 

Not  much  is  known  of  ozone.  Whence  comes  it,  or  how  is 
it  elaborated?  Some  maintain  that  it  is  generated  by  electrical 
discharges  and  explosions.  If  so,  then  the  equatorial  calms  and 
cloud  ring  would  fulfill  the  conditions  of  the  great  laboratory  of 
nature  for  this  subtilty»  A  regular  and  systematic  series  of  ozo- 
nometrical  observations  on  board  ships  at  sea  might  throw  much 
light  upon  the  circulation  of  the  atmosphere  by  converting  the 
ozone  into  tallies  for  the  winds.  It  is,  therefore,  to  be  desired, 
that  those  who  are  co-operating  with  me,  by  making  observations 
to  assist  in  the  investigation  of  the  phenomena  of  winds  and  sea  for 
the  benefit  of  navigation,  will  extend  their  field  of  research  by  di- 
rectino;  their  attention  to  the  ozonometer  also. 

When  I  first  received  the  account  of  Lieutenant  Jansen's  ob- 
servations, which  so  clearly  marked  the  excessive  presence  of  ozone 
in  winds  coming  from  the  equator  as  compared  with  winds  coming 
from  the  poles,  I  had  not  seen  any  account  of  either  Pegado's  or 
Eogers's  observations,  and  fell,  therefore,  into  the  error,  perhaps, 
of  attaching,  in  an  addendum  to  the  sixth  edition  of  this  work, 
undue  importance  to  a  single  series  of -observations.  The  results 
of  the  observations,  now  that  they  begin  to  multiply  at  sea  and  on 
land,  and  in  different  parts  of  the  world,  appear  to  differ  so  much 
from  each  other  in  certain  aspects,  that  it  will  require  many  series 
of  carefully-made  observatl'ins  before  we  can  reasonably  hope  to 
generalize  boldly  and  with  confidence  touching  this  new  substance. 

This  invisible  substance,  like  magnetism  and  sea-dust,  is  a  gos- 
samer-like clew,-  intended  to  guide  us  through  the  mazes  of  the  air, 
and  along  the  paths  of  the  wind.  But,  because  it  is  invisible,  im- 
palpable, and  fine,  we  want  so  much  the  more  to  trace  it  up  by 
the  foot-prints  it  makes,  and  ascertain  the  secrets  of  its  chambers.* 

*  Dr.  Breed,  of  Washington,  has  very  kindly  furnished  me  with  the  following  rec- 
ipe for  ozone  paper : 


ADDENDA.  351 

Page  172,  §  472. 

Commander  Eodgers,  while  commanding  the  North  Pacific  Sur- 
veying Expedition,  passed  up  into  the  Arctic  Ocean  through  Behr- 
ing's  Strait.  He  has  had  the  kindness  to  furnish  me  with  his  ob- 
servations for  temperature  and  specific  gravity  of  the  water  at  the 
surface  of  that  ocean,  midway,  and  at  the  bottom.  These  observa- 
tions throw  light  from  a  new  quarter  upon  whtit  has  already  been 
said  concerning  an  open  water  in  the  Arctic  Ocean.  They  are  of 
exceeding  interest  and  value  in  that  light.  In  all  the  experiments 
there,  he  invariably  found  warm  and  light  water  at  the  top,  cold 
water  in  the  middle,  and  hot  and  heavy  water  at  the  bottom. 

Observations  ox  Specific  Gratitt  and  Deep-Sea  Temperature  (U.  S.  Ship 

ViNCEN-NES,  Commander  John  Eodgers,  Commanding). 

August  13,  1855.— Lat.  72°  02'  27"  N.,  long.  174°  37' 00"  W. 

Sea  smooth;  temperature  of  air ^  45.2°. 

Water  in  CrLrxDEK. 


Temperature. 

Specific  Gravity.  ^ 

1st  Trial. — At  surface 

43.8 

1.0264 

"  20  fathoms. 

33.5 

1.02GG 

"  40       "       . 

40.5* 

1.0266 

2d  Trial.  —  At  surface 

43.7 

1.0264 

"  20  fathoms. 

34  . 

1.0266 

"  40       " 

41* 

1.0266         J 

Depth,  15  fathoms. 


Depth,  40  fathoms. 


*  Within  2  feet  of  the  bottom. 

August  14th.— Lat.  71°  21'  30"  N.,  long.  175°  22'  00"  W. 
Sea  smooth;  temperature  of  air,  45°. 

Wateb. 
Temperature.  Specific  Gravity. 

1st  Trial.— At  surface 44  1.0256 

"  12  fathoms 33.5  1.0027 

"  15       "       37.5*  1.0027  \> 

2d  Trial.— At  surface 43.8  1.0256 

"12  fathoms 33  1.0268 

"  15       "       37*  1.0270         ) 

*  Near  the  bottom.  • 

Starch,  10  parts  ;  iodide  of  potassium,  20  parts  ;  water,  400  parts.  Mix,  dip  pa- 
per in  the  mixture,  and  dry.  Preserve  the  paper,  folded,  in  a  close  vessel.  For 
use,  a  scale  of  colors  should  be  prepared,  with  which  to  compare  the  deepness  of  the 
colors  produced  by  ozone.  When  making  the  observation,  the  test  paper  should  be 
placed  where  the  air  has  free  access. 

Diseases  are  thought  to  be  more  or  less  prevalent  according  to  the  abundance  of 
ozone  in  the  air.  The  medical  staff  of  the  navy,  in  their  cruises  abroad,  have  fine 
opportunities  of  throwing  light  on  this  subject. 


352  ADDENDA. 

August  14tli.— Lat.  71°  21'  30"  N.,  long.  175°  22'  00"  W. 
Sea  smooth;  strong  current  to  N.  hy  W.;  temperature  of  air  ^  45°. 

Water. 
Temperature.  Specific  Gravity.  •\ 

At  surface 44  -       1.0256  I 

"  10  fathoms 33.4  1.0268         > Depth,  25  fathoms. 

"  25       "       37.3*  1.0268         J 

*  Near  the  bottom. 

August  15th.— Lat.  71°  21'  30"  N.,  long.  175°  22'  00"  W. 
Temperature  of  air ^  45°. 

"Watee. 
Temperature.  Specific  Gravity.  ^ 

At  surface 42.5  1.0258  i 

"    12  fathoms 39.8  1.0264  > Depth,  25  fathoms. 

"   25       "       40.2*  1.0264         J 

*  Very  near  the  bottom. 

August  16th,  8h.  30m.  A.M.— Lat.  71°  16'  00"  N.,  long.  176°  05'  00"  W. 
Wind  from  the  southward ;  temj^erattu'e  of  air,  ^7. 5°. 

Watee. 
Temperature.  Specific  Gravity,  -n 

At  surface 38.2  1.0246  i 

"  15  fathoms 31.6  1.0256  j>Depth,  31  fathoms. 

"  31       "        34*  1.0258         J 

*  Very  near  tlic  bottom. 

August  17th,  11  A.M.— Lat.  68°  42'  00"  N.,  long.  174°  27'  30"  W. 
Sea  smooth — calm;  temperature  of  air,  48.6°. 

Watee. 
Temperature.  Specific  Gravity.  ^ 

At  surface 45  1.0264  _      , 

«  20  fathoms 38  1.0271  >  Depth,  28  fathoms. 

"  28        "      40.2*  1.0271         J 

1  *  Very  near  the  bottom. 

Here  the  sea  is  shallow,  and  we  may  suppose  that  this  arrange- 
ment or  stratification  is,  as  these  observations  indicate,  even  more 
striking  in  the  deep  water  of  the  Polar  hasih  than  it  is  where  these 
observations  were  made.  An  extensive  layer  of  water  at  the  tem- 
perature of  40°  would,  when  brought  to  the  surface  in  those  hyper- 
borean regions,  tend  mightily  to  mitigate  and  soften  climates  there. 

The  water  was  obtained  at  these  various  depths  by  means  of  a 
cylinder  contrived  for  the  purpose. 

Now  the  question  is.  How  did  this  hot  and  heavy  water  that 
was  found  at  the  bottom  get  there  ?  Did  it  come  through  Behr- 
in2:'s  Strait  with  the  warm  water  of  the  surface  ?  or  did  the  Gulf 

o 


ADDENDA.  353 

Stream  pour  it  into  the  Polar  basin  ?  A  conclusive  answer  would 
be  instructive.  It  is  worthy  of  remark,  that  the  water,  both  at  the 
top  and  the  bottom,  is  lighter  than  sea-water  in  the  torrid  zone ; 
fresh  water  has  therefore  been  mixed  with  it  since  it  last  supplied 
the  trade  winds  with  vapor. 

THE  BASIN  OF  THE  ATLANTIC,  p.  265,  (J  761. 

A  collection  of  deep-sea  specimens  has  just  been  obtained  from 
the  telegraphic  plateau  of  the  Atlantic  all  the  way  across  from 
Newfoundland  to  Ireland.  The  United  States  steamer  Arctic, 
Lieutenant  O.  H.  Berry  man,  was  sent  to  sea  last  summer  under 
the  law  of  1849  (§  689).  She  ran  a  line  of  deep-sea  soundings 
across  the  Atlantic,  and  reported  bottom,  Avith  specimens,  at  some- 
what regular  intervals  along  the  great-circle  route  from  the  offings 
of  Saint  John  to  those  of  Valentia.*  These  treasures,  on  being 
transmitted  to  the  Observatory,  were  submitted  to  Professor  Bai- 
ley, of  West  Point,  for  microscopic  examination.  As  usual  with 
all  the  specimens  of  bottom  heretofore  obtained  from  the  deep  sea, 
these  have  turned  out  to  be  highly  interesting,  instructive,  and 
suggestive.  The  results  of  this  cruise,  as  far  as  they  may  be  re- 
lied on,  confirm  all  that  has  been  said  concerning  the  bottom  of 
the  Atlantic,  its  soft  character  (§  759),  its  quiescent  state  (§  761), 
and  its  adaptation  (§  714  and  §  721)  for  a  telegraphic  cable. 

The  first  glance  into  these  specimens  from  deep  water  revealed 
the  doings  of  the  Gulf  Stream,  that  hearse  of  the  sea.  The  re- 
mains of  the  tenants  of  the  deep  lie  buried  and  scattered  there  in 
piles  and  beds  of  vast  extent.  The  specimens  from  Newfound- 
land, as  far  out  as  the  northeastern  edge  of  the  Grand  Banks, 
abound,  for  the  most  part,  in  Polar  drift ;  but  as  you  get  out  far- 
ther and  farther  into  blue  water,  and  midway  in  the  Gulf  Stream, 
the  calcareous  organisms  become  more  and  more  abundant. 

Professor  Bailey,  in  a  private  note,  thus  speaks  of  these  speci- 
mens as  they  appeared  at  first  sight : 

"  I  have  only  had  a  few  hours  this  afternoon  to  look  at  the 
*  beauties.'     From  what  I  have  seen  of  them,  I  judge  that  they 

*  The  depths  reported  with  these  specimens  unfortunately  were  all  wrong,  and  had 
to  be  rejected  as  worthless. 


354  ADDENDA. 

will  confirm  in  every  respect  the  results  of  tlie  previous  soundings 
made  in  about  the  same  regions.  There  is  evidently  a  drift  from 
the  north  of  coarse  mineral  matter,  which  is  deposited  in  the  neigh- 
borhood of  the  Banks ;  but  all  the  rest  of  the  way  clear  across, 
and  approaching  pretty  closely  to  the  British  shore,  the  whole  bot- 
tom is  a  fine  calcareous  mud,  containing  no  particles  of  mineral 
matter  as  large  as  a  mustard-seed,  and,  in  fact,  almost  wholly 
made  up  of  perfect  shells  of  Foraminifera,  a  fine  mud  produced  by 
their  decay,  and  a  smaller  portion  of  silicious  organisms,  such  as 
Diatoms,  Polycistias,  sponge  spicales,  etc. 

"From. the  results  of  three  slides  which  I  mounted  to-day,  I 
expect  to  find  almost  a  perfect  correspondence  of  the  species  to 
those  already  noticed  in  the  deep  soundings  of  the  Atlantic.  I 
have  noticed  no  new  species  as  yet,  but  have  scarcely  glanced  at 
the  slides. 

"The  specimens  I  mounted  to-day  were  No.  20,  lat.  52°  01^, 
long.  17°  06^  in  its  natural  state  ;  No.  20,  lat.  52°  OV,  long.  17° 
06^,  acted  upon  by  chlorohydric  acid;  No.  11,  lat.  51°  15^,  long. 
34°  08^,  in  its  natural  state. 

"  The  specimens  in  natural  state  gave  great  numbers  of  micro- 
scopic Foraminifera  (with  an  occasional  granule  of  quartz,  etc.,  of 
microscopic  minuteness),  and  here  and  there  a  Diatom  or  Polycis- 
tia  could  be  seen. 

"In  the  specimen  cleaned  by  acid,  the  calcareous  mud  being 
dissolved  out,  the  silicious  particles  were  left,  and  among  these  an 
abundance  of  Diatoms,  Polycistias,  and  Sj)ongiolites  were  found. 

"  I  have  no  doubt  our  beautiful  '  ocean  river'  glides  along  its 
course  in  the  Northern  Atlantic  as  gently  as  the  current  of  time, 
dropping  now  and  then  a  defunct  animalcule  into  the  great  sepul- 
chre below,  but  not  wearing  or  abrading  the  bottom  in  the  slight- 
est degree." 

A  week  after  he  again  writes : 

"  Well,  I  have  something  new  that  will  set  you  thinking.  I 
have  been,  digging  away  in  the  muds,  getting  deeper  and  deeper 
from  No.  1  (lat.  47°  50^  long.  52°)  to  No.  15  (lat.  52°  26',  long. 
26°  20^)  and  16  (lat.  52°  2',  long.  24°  51^,  finding  the  calcare- 
ous organisms  increasing  in  number  as  I  got  east,  when,  all  of  a 


ADDENDA.  355 

sudden,  what  should  I  run  foul  of  but  Mount  Ilecla  !  The  spec- 
imens Nos.  15  and  16,  like  most  of  those  which  immediately  pre- 
cede, contain  much  calcareous  mud  and  many  calcareous  Poly- 
thalamia,  from  whose  decay  the  mud  was  derived.  By  dissolving 
out  this  mud  by  chlorohydric  acid  and  examining  the  residue,  the 
specimens  all  left  some  fine  sand,  generally  quartzose,  and  with 
sharp  angles ;  but  No.  15  and  No.  16  gave  a  considerable  portion 
of  well-characterized  volcanic  ashes,  composed  of  glassy  obsidian 
and  minute  fragments  of  pumice.  There  can  be  no  mistake  about 
it :  the  glassy  matter  ]ias  the  conchoidal  fracture,  the  sharp  edges, 
and  dark  color  of  volcanic  glass,  while  the  grains  of  pumice,  al- 
though of  microscopic  size,  show  the  contorted  vesicles  in  which 
was  confined  the  gas  which  distended  the  mass.  I  find  no  evi- 
dence of  any  violent  abrasion  in  any  of  the  specimens  ;  even  in  the 
coarse  ones  from  near  tlie  Banks,  the  matter  has  usually  sharp 
angles,  and  is  such  as  might  be  dropped  from  icebergs  as  they 
melt,  without  undergoing  any  subsequent  abrasion  or  transporta- 
tion." 

I  could  not  perceive  how  these  cinders  could  have  got  there 
from  Hecla  or  any  of  the  extinct  volcanoes  of  Iceland ;  nor  could 
I  perceive  how,  if  they  came  from  the  volcanoes  of  intertropical 
America,  they  should  be  found  only  in  the  narrow  space  between 
the  meridians  of  25°  and  26°  30^  W.,  along  the  parallel  of  52°.  I 
asked  the  professor  to  "try  back,"  and  expressed  the  opinion,  if 
they  came  from  the  south,  that  they  would,  as  far  north  as  that 
parallel,  be  found  all  the  way  across  the  eastern  half  of  the  At- 
lantic, and  as  far  toward  the  Irish  coast  as  the  deep  water  goes. 
He  did  so,  and  immediately  reported  the  presence  of  cinders  in  ev- 
ery specimen  along  a  line  more  than  1000  miles  in  length. 

"From  No.  11  up  to  No.  20,  inchisive  of  both,'"  says  he,  "the 
microscopic  bits  of  pumice  and  obsidian  (or  smoky  volcanic  glass) 
are  unmistakably  present.  No.  10  I  must  look  at  again.  I  think 
that  it  also  has  volcanic  matter  in  it,  but  I  must  make  another 
special  search  for  it  before  I  pronounce  positively. 

"The  evidence  of  want  of  abrasion  of  the  mineral  matter,  and 
the  presence  of  a  large  proportion  of  fine  calcareous  mud  with 
Gulf  Stream  forms,  continues  in  all  the  specimens  yet  examined." 

Z 


356  ADDENDA. 

After  still  further  examination  he  wrote : 

"  The  volcanic  debris,  as  you  predicted,  does  stretch  well  across 
from  where  it  was  first  noticed.  It  is  present  in  all  the  deep 
soundings  up  to  21  (lat.  52°  5",  long.  16^  5'),. which  gave  some 
minute  but  very  well  characterized  pumice-like  fragments.  In 
Nos.  22  and  23"  (both  east  of  15°  20^  W.),  ''  I  have  detected 
nothing  that  I  could  positively  declare  to  be  of  volcanic  origin. 
No.  22  gave  for  the  heavy  parts  some  fine  quartz  sand,  with  mi- 
croscopic globules  of  iron  pyrites,  and.  some  bits  of  hornblende 
and  feldspar." 

The  health  of  Professor  Bailey  is  feeble,  and  on  that  account  he 
could  attack  these  interesting  specimens  only  now  and  then.  But 
on  the  16th  of  October  he  reported, 

"  On  the  back  track:  I  tried  No.  8  to-day,  and  being  on  the 
look-out  for  pumice,  found  it  on  a  mounted  slide,  where  it  has  es- 
caped my  attention  in  my  first  experiments.  I  then  dissolved  a 
new  portion  of  material,  and  detected,  without  difficulty,  several 
pieces  of  undoubted  pumice  in  the  residue.  By  'pumice'  I  mean 
a  nearly  colorless  volcanic  glass,  which  has  been  distended  by  gas- 
es, and  shows  vesicles,  ridges,  conduplications,  etc.,  which  only 
such  a  body  could  show. 

"  It  is,  then,  a  fixed  fact  that,  from  No.  8  (lat.  50°  2^  long.  38° 
30^  on  one  side,  up  to  No.  21  (lat.  52°  b\  long.  16°  5^),  inclusive, 
on  the  other,  we  have  the  volcanic  debris  !  I  looked  at  No.  7  (lat. 
50°  3',  long.  40°  26^)  again,  but  could  detect  nothing  that  I  felt 
sure  of  as  volcanic.  In  the  marginal  specimens,  the  volcanic  mat- 
ter is  in  small  proportion,  and  may  easily  be  overlooked ;  but  in 
No.  14  (lat.  52°  26^  long.  27°  18^),  it  is  so  abundant  and  well 
characterized  that  it  can  not  be  missed. 

"As  you  know  all  that  is  known  about  the  great  currents  of 
the  ocean,  you  can,  better  than  any  one,  make  use  of  these  '  Plu- 
tonic tallies.'  I  Imd  forgotten  that  the  Gulf  Stream  sometimes 
brushes  the  Azores.  It  is  not  necessarily  from  any  active  vol- 
cano that  these  matters  come.  The  washing  away  of  ancient  vol- 
canic sands  would  give  '  ocean  dus.t'  enough  for  our  purposes. 
This  dust,  however,  is  much  heavier"  (and  would  therefore  sink 
faster)  "than  the  organic  tallies  I  have  been  accustomed  to  look  for." 


ADDENDA.  357 

It  was  tliouglit  they  might  possibly  be  steam-boat  ashes,  as  the 
steamers  that  ply  between  this  country  and  Europe  pass  that  way. 
Specimens  of  these  were  obtained  from  the  ash-pit  of  the  Baltic  and 
other  sea  steamers,  and  examined  through  the  microscope.  The 
examination  only  satisfied  the  professor  still  more  completely  as 
to  the  volcanic  origin  of  the  others. 

Thus  the  question  is  fairly  presented.  Where  did  these  "  Plu- 
tonic tallies"  upon  the  currents  of  the  ocean  come  from  ?  Did 
they  come  from  the  volcanoes  of  Mexico  and  Central  America, 
which  have  been  known  to  cast  their  ashes  into  the  Gulf  of  ]\Iex- 
ico,  and  even  as  far  as  the  island  of  Cuba  ?  If  so,  the  Gulf  Stream 
would  have  strewed  them  along  the  coast  of  the  United  States. 
But  specimens  from  the  bed  of  the  Gulf  Stream  off  our  coast  have 
been  obtained  by  the  Coast  Survey,  and  subjected  to  the  micro- 
scope, and  no  volcanic  cinders  have  been  found  in  them.  This 
negative  fact,  together  with  the  positive  one  that  they  are  heavier 
than  the  organic  tallies  which  mark  the  footprints  of  the  Gulf 
Stream  as  it  travels  across  the  ocean,  seemed  to  place  those  vol- 
canoes as  the  source  of  these  cinders  out  of  the  question. 

'Nov  do  I  perceive  by  what  channel  they  could  have  been  con- 
veyed to  the  place  where  the  deep-sea  apparatus  fished  them  up 
from  any  of  the  volcanoes  that  are  now  in  activity.  They  were 
out  of  beat  of  the  East  Greenland  current,  and  seemed  to  be  too 
heavy  to  carry  far.  I  therefore  turned  to  the  region  of  extinct 
volcanoes,  and  was  immediately  led  to  suspect  the  Western  Isl- 
ands as  the  probable  source.  The  fact  that  the  cinders  were 
coarse  and  heavy  in  comparison  with  the  shells  among  which  they 
were  found  is  very  suggestive,  for  it  tends  to  confirm  this  conjec- 
ture. That  no  traces  of  volcanic  action  are  found  except  in  the 
deep  trough  of  the  Atlantic,  would  seem  to  indicate  that  in  this 
part  of  the  Gulf  Stream  they  had,  on  their  way  to  the  north,  sunk 
below  the  submarine  step  which  leads  up  from  the  depth  of  the 
ocean  to  soundings  off  the  Irish  coast.* 

These  specimens — bits  of  down  from  the  bed  of  the  ocean — ap- 

*  Captain  Stellwagen,  U.  S.  Navy,  has  just  informed  me  that  the  New  England 
fishermen  often  bring  up  with  their  hooks  specimens  of  volcanic  scoria  from  the 
south  shoals  of  Nantucket. 


358  ADDENDA. 

pear  fully  to  confirm  all  that  I  have  previously  advanced  concern-^ 
ing  the  bottom  of  the  deep  sea  and  the  adaptation  of  this  part  of 
the  Atlantic  for  a  telegraphic  cable.  My  investigations  show  that 
the  bottom  is  so  free  from  currents  and  abrading  agents  that  a 
rope  of  sand,  if  once  laid  there,  would  be  stout  enough  to  with- 
stand the  pulling  of  all  the  forces  that  are  at  play  upon  the  bottom 
of  the  deep  sea. 

Many  are  the  great  truths  of  nature  which,  when  once  suggest- 
ed, appear  so  obvious  and  simple  that  we  wonder  why  reason  did 
not  suggest  them,  or  common  sense  point  them  out  before.  So  it 
appears  with  this  cushio7i  of  still  water  which  seems  to  be  every 
where  interposed  between  the  bottom  of  the  deep  sea  and  its  cur- 
rents. We  are  surprised  now  that  it  never  occurred  to  us  that  it 
must  be  so ;  how,  if  it  were  not  so,  the  scouring  action  of  such  cur- 
rents upon  the  bed  of  the  ocean  would  have  worn  it  into  deep 
scores,  furrows,  and  gashes,  which,  the  deeper  they  grow,  the  faster 
they  would  wear,  until  finally  the  solid  crust  of  our  planet  would 
have  been  worn  through.  Thus,  while  the  deep  places  would  grow 
deeper,  the  shallow  places  would  grow  shallower,  the  proportion 
of  land  and  water  surface  would  be  altered,  and  thus  that  beauti- 
ful system  of  terrestrial  economy  which  regulates  the  amount  and 
kind  of  work  to  be  performed  by  every  one  of  the  myriads  of  phys- 
ical agencies  that  have  been  employed,  under  the  guidance  of  su- 
preme intelligence  since  the  beginning,  in  bringing  this  world  to 
the  state  in  which  we  actually  find  it,  would  have  been  marred 
long  ago. 

If  the  currents  do  now  and  then  press  too  heavily  upon  this 
fending  cushion  of  still  and  heavy  water,  and  wear  holes  or  hol- 
lows in  it,  as  they  probably  do,  it  is  self-adjusting,  and  as  soon  as 
the  occasion  which  called  for  this  wearing  passes  by,  the  shielding 
water  below  returns  to  its  place  by  the  force  of  hydrostatic  pressure. 
Brooke's  sounding-rod  has  brought  up  from  the  depth  of  more 
than  2000  fathoms  under  the  Gulf  Stream  the  remains  of  organ- 
isms so  delicate,  yet  so  perfect,  that  evidently  they  had  never  been 
rolled  along  the  bottom  of  the  sea  by  any  current.  At  the  depth 
of  2000  fathoms  in  the  sea  the  pressure  is  6000  pounds  upon  a 
square  inch.     Suppose  wx  imagine  the  currents  of  the  Gulf  Stream, 


ADDENDA.  359 

where  it  is  four  knots  the  hour,  to  be  2000  fathoms  in  depth,  and 
to  reach  down  to  the  bed  of  the  ocean  with  that  velocity  and  press- 
ure, the  scouring  action  of  water  under  such  a  weight  and  mo- 
tion would  fret  and  wear,  break  and  tear  up  the  very  bed  and  bot- 
tom of  the  sea. 

The  discovery  of  facts  like  these  has  proved  of  the  greatest  val- 
ue to  those  concerned  in  establishing  lines  of  submarine  telegraph. 
The  French  government,  in  ignorance  of  the  status  of  the  deep  sea, 
has  made  two  attempts  to  lay  a  cable  from  Sardinia  to  Al,2:eria. 
There  was  failure  each  time,  with  great  loss,  for  the  cable  was  one 
of  iron  wire,  of  immense  weight,  and  stout  enough  to  hold  the  lar- 
gest ship,  but  the  currents  and  the  storms  parted  it,  or  made  it 
necessary  for  those  on  board  to  cut  or  perish.  Its  core  was  of 
gutta  percha,  in  which  were  contained  the  conducting  wires. 

The  systematic  attempt  to  explore  the  depths  of  the  sea,  and  to 
investigate  its  winds  and  currents,  which  has  been  inaugurated  at 
the  National  Observatory,  has  brought  to  light  the  fact  that  the 
core  alone,  without  the  iivn  cable,  or  any  casing  save  that  of  the 
insulating  material,  is  strong  enough  to  resist  all  forces  at  the  bot- 
tom of  the  sea ;  that  the  forces  of  the  currents  through  which  the 
cable  has  to  sink  and  while  it  is  sinking  are  the  forces,  and  the 
only  forces,  which  try  its  strength  ;  and  if  resistance  be  offered,  no 
cable,  as  the  French  have  proved,  is  strong  enough  to  withstand 
them  and  sink.  It  was  a  cable  of  this  sort  which  was  lost  in  the 
laying  between  Newfoundland  and  Cape  Breton  during  the  sum- 
mer of  1855.  The  currents  of  the  sea  are  to  be  overcome,  not  by 
resisting,  but  by  yielding.  The  sea,  if  obstruction  or  resistance 
be  offered  to  its  waves,  will  dash  the  strongest  works  of  man  to 
pieces,  and  sport  with  the  wreck  like  toys,  while  the  tiny  nauti- 
lus, by  yielding  to  them,  will  defy  the  most  violent  ragings  of  the 
sea,  and  ride  its  billows  triumphantly  in  the  utmost  fury  of  the 
storm.  So  with  the  gutta  percha  core  and  its  conducting  wire  of 
copper :  if  it  be  paid  out  slack  into  the  deep  sea,  so  that  it  will 
yield  to  the  currents,  drifting  with  them  hither  and  thither  while 
it  is  sinking  through  them,  it  will  soon  pass  beyond  their  reach, 
and  be  lodged  on  the  bottom  without  any  the  slightest  trial  of  its 
strength. 


360  ADDENDA. 

The  Atlantic  Telegrapliic  Company,  availing  itself  of  this  princi- 
ple, have,  instead  of  attempting  to  span  the  ocean  with  a  wire  ca- 
ble, which  would  require  several  ships  to  transport,  wisely  decided 
to  use  a  single  conducting  thread  of  copper,  or  a  fascicle  of  them, 
coated  to  insulation  with  gutta  percha,  and  properly  protected. 
Instead  of  being,  like  the  lost  French  cables  of  the  Mediterranean, 
as  large  as  a  man's  arm,  this  for  the  Atlantic  will  probably  not  be 
larger  than  his  finger,  and  one  vessel  can  carry  enough  to  reach* 
across  and  lay  it  out. 

I  speak  with  caution,  and  with  a  due  sense  of  the  responsibility 
I  incur,  but  I  think  the  researches  and  discoveries  in  this  field 
warrant  me  in  saying  that  there  is  no  limit  but  the  electrical  one 
to  the  length  of  wires  of  submarine  telegraph  that  may  be  estab- 
lished ;  that,  in  deep  water,  telegraphic  w^ires  may  be  laid  across 
the  Indian  and  Pacific  Oceans  as  well  as  across  the  Atlantic  and 
Mediterranean ;  that  they  may  be  laid  in  any  direction ;  that  the 
expense  of  laying  a  thousand  miles  of  telegraphic  wire  —  for  we 
should  call  it  cable  no  longer — in  the  deep  sea  need  not  exceed  the 
expense  of  stretching  a  wire  of  equal  length  over  the  land ;  and 
furthermore,  that  there  is  this  difference  in  favor  of  the  subma- 
rine telegraph :  once  at  the  bottom  of  the  deep  sea,  there  will  be  no 
wear  and  tear  as  for  the  renewal  of  posts,  wires,  and  the  like  on  the 
land,  and  no  interruption  of  communication  by  storm  and  accident. 
In  shallow  water  and  "  on  soundings"  there  will  be  such  liability. 
I  speak  alone  of  the  deep  sea,  and  upon  the  assumption  that  the 
durability  of  gutta  percha  is  lasting,  and  its  insulating  powers 
proof  against  the  hydrostatic  pressure  of  the  ocean. 

Professor  Morse  has  passed  telegraphic  signals  through  an  un- 
broken w^re  "upward  of  2000  miles  in  length"  at  the  rate  of  270 
per  minute.  This  was  passed  through  gutta  percha  coated  wires 
under  ground.  How  far  can  they  be  passed  through  submarine 
wires  ?  The  answer  to  this  question,  and  not  the  depth  of  the  sea, 
will  express  and  fix  the  limit  of  maximum  length  to  lines  of  sub- 
marine telegraph. 

December,  1856. 


APPENDIX. 


THE  ATLANTIC  TELEGRAPH. 

The  Atlantic  Cable  quietly  rests  on  its  plateau,  and  tlie  laying 
of  it  lias  been  celebrated  with  a  pomp  and  circumstance  seldom  if 
ever  witnessed  on  any  occasion  in  tliis  country  before.  It  is  a 
great  achievement,  and  is  so  considered  by  the  people  of  all 
Christendom.  Every  thing  that  contributed  toward  its  accom- 
plishment is  now  possessed  of  that  peculiar  interest  which  attaches 
to  the  history  of  great  events. 

'  It  is  in  some  sort  a  result  arising  from  our  knowledge  concern- 
ing the  physics  of  the  sea,  and  a  short  account  of  it  may  be  given 
here  without  prejudice  to  the  specialties  of  this  work. 

On  the  1st  September,  before  an  immense  assembly  of  people 
in  the  Crystal  Palace  of  New  York,  the  history  of  this  telegraphic 
enterprise  was  given,  in  a  speech  of  much  beauty  and  eloquence, 
by  David  Dudley  Field,  for  and  in  behalf  of  the  company — he 
being  one  of  the  original  projectors. 

In  1854  he  and  his  associates  had  under  consideration  a  line 
from  our  own  shores  to  ISTewfoundland,  when  the  idea  of  extend- 
ing it  across  the  Atlantic  was  suggested ;  but  before  they  decided 
upon  any  thing  they  wrote,  said  the  orator,  ''  to  Lieutenant  Maury 
to  inquire  about  the  practicability  of  submerging  a  cable,  and 
consulted  Professor  Morse  about  the  possibility  of  telegraphing 
through  it.  Their  answers  were  favorable.  On  receiving  them 
it  was  decided  to  '  go  ahead.' " 

It  thus  appeares  that  this  new  department  of  science  embodied 
in  the  term  "  Physical  Greography  of  the  Sea"  has  already  contrib- 
uted to  the  advancement  and  success  of  one  of  the  grandest  and 
most  interesting  practical  problems  which  this  age  of  mind  and  in- 
telligence has  been  called  on'  to  demonstrate. 

In  the  summer  of  1857,  the  United  States  steamer  Niagara  and 
H.  B.  M.  steamer  Agamemnon  were  assigned  by  their  respective 
governments  to  the  duty  of  receiving  on  board  and  laying  the 


362  APPENDIX. 

Submarine  Atlantic  Cable.  Other  vessels  were  sent  witli  tbem  as 
pilots,  consorts,  and  tenders.  The  plan  was  for  the  Niagara  to 
begin  at  Queenstown,  Ireland,  pay  out  her  cable  as  far  as  it  would 
reach,  then  pass  the  end  in  mid-ocean  to  the  Agamemnon,  when 
it  would  be  spliced,  and  when  that  ship  would  proceed  with  it  to 
Newfoundland.  After  reaching  deep  water,  the  Niagara  having 
paid  out  about  344  miles  of  cable,  it  parted  August  11th,  1857. 
This  failure  postponed  farther  trial  till  the  summer  of  1858. 

In  the  summer  of  1858  the  same  two  ships,  having  the  cable 
again  on  board,  proceeded  together  to  mid-ocean,  where  the  two 
ends  were  joined,  and  they  then  commenced  to  "  pay  and  go," 
each  toward  her  own  land.  The  Niagara  had  1488  miles  of  cable 
on  board,  the  Agamemnon  1477.     Total,  2965  miles. 

After  three  unsuccessful  attempts  to  lay  the  cable,  and  after  the 
loss  of  about  400  miles  of  it,  the  fleet  returned  to  Ireland.  It  put 
to  sea  again  for  a  last  trial  July  17,  with  about  1274  miles  of  ca- 
ble on  board  each  of  the  paying-out  vessels. 

They  met  in  mid-ocean,  joined  cables,  and  set  out — the  Niagara 
for  her  terminus  in  Trinity  Bay,  and  the  Agamemnon  for  hers 
in  Valentia  Harbor — at  1  P.M.,  July  29th,  and  successfully  landed 
each  vessel  her  end  of  the  cable  on  the  5th  of  August.  One  week 
after  that  messages  of  congratulation  were  passed  through  the 
cable  between  the  Queen  of  England  and  the  President  of  the 
United  States. 

The  part  which  the  Observatory  has  played  in  the  history  of 
submarine  telegraphy,  and  of  this  line  between  the  Old  World  and 
the  New,  is  a  quiet  and  an  humble  part ;  nevertheless,  it  now  ap- 
pears to  have  been  an  important  and  useful  part.  But,  whatever 
it  may  have  been,  it  has  grown  out  of  that  beautiful  system  of 
research  concerning  the  physics  of  the  sea,  which,  having  its  com- 
mencement here  in  1842,  has  expanded,  and  blossomed,  and  fruit- 
ed, giving  among  its  fruits  for  man's  benefit  charts  of  the  winds 
and  currents  of  the  sea,  and  secrets  snatched  from  its  depths.  The 
present,  therefore,  seems  to  be  a  proper  time  for  placing  on  record 
a  statement  showing  the  connection  of  the  Observatory  with  this 
enterprise,  and  the  part  borne  in  it  by  each  one  who  has  helped 
this  institution  to  render  good  service  in  such  a  field. 

In  1849  the  labors  of  the  Observatory  in  the  hydrographical 
department  of  its  duties  appear  to  have  attracted  the  favorable 


APPENDIX.  353 

consideration  of  Congress ;  for  in  Marcli  of  that  jear  a  law  was 
passed  directing  the  Secretary  of  the  Kavy  "  to  detail  three  suit- 
able vessels  of  the  navy  in  testing  new  routes  and  perfecting  the 
discoveries  made  by  Lieutenant  Maury  in  the  course  of  his  inves- 
tigations of  the  winds  and  currents  of  the  ocean ;  and  to  cause  the 
vessels  of  the  navy  to  co-operate  in  procuring  materials  for  such 
investigations,  in  so  far  as  said  co-operation  may  not  be  incompat- 
ible with  the  public  interest." 

Under  this  law  the  United  States  schooner  Taney,  Lieutenant 
J.  C.  Walsh  commanding,  was  sent  to  sea  in  1849.  She  was 
directed,  among  other  things,  to  make  a  series  of  deep-sea  sound- 
ings. She  was  provided  therefor  with  fourteen  thousand  fath- 
oms of  steel  wire,  and  a  self-registering  deep-sea  sounding  appa- 
ratus, made  by  Mr.  Baur,  of  New  York,  from  drawings  and  ac- 
cording to  a  plan  designed  in  this  ofQ.ce.  She  got  a  cast  with 
5700  fathoms  of  line  out,  when  it  parted,  losing  the  apparatus. 
She  then  proved  unseaworthy,  was  condemned,  and  sent  back 
under  escort. 

This  reported  sounding  served  to  stimulate  that  longing  which 
is  implanted  in  the  human  breast  touching  the  mysteries  and  the 
wonders  of  the  great  deep ;  for  up  to  this  time  no  systematic  at- 
tempt had  ever  been  made  to  fathom  the  deep  sea.  Sporadic  casts- 
of  the  lead  had  been  made  here  and  there  in  "blue  water,"  but 
though  the  reported  depths  had  been  great,  yet,  as  with  that  of 
the  Taney,  there  always  remained  a  doubt  as  to  whether  bottom 
had  been  reached  or  not,  and  at  what  depth.  Up  to  this  time  we 
were  as  ignorant  as  to  the  real  depths  of  the  ocean,  and  the  true 
character  of  that  portion  of  the  solid  crust  of  our  planet  which 
constitutes  its  bed,  as  we  are  at  this  moment  of  the  interior  of  one 
of  the  satellites  of  Jupiter.  Using  astronomical  elements,  the 
mean  depth  of  the  ocean  had  been  calculated  to  be,  according  to 
theory,  about  23  miles. 

My  excellent  friend,  the  late  Commodore  "Warrmgton,  who  was 
then  the  chief  of  the  Bureau  of  Ordnance  and  HydrograjDhy,  of 
which  the  Observatory  is  a  branch,  took,  as  was  his  wont,  liberal 
and  enlightened  views  touching  the  plan  of  deep-sea  soundings 
now  proposed.  The  Secretary  of  the  Navy  regarded  it  with  a 
lively  interest ;  he  was  ready  to  afford  every  facility  that  the  law 
required,  and  the  law  itself  was  liberal  enough.     Under  such  au- 


36'4  APPENDIX. 

sjDices,  it  was  decided  to  inaugurate  a  regular  plan  of  deep-sea 
soundings  for  tlie  American  navy.  Accordingly,  formula3  were 
arranged,  methods  prescribed,  and  every  vessel  was  furnished  with 
the  requisite  twine,  etc.,  and  commanded  to  use  every  suitable  and 
convenient  opportunity  while  at  sea'  to  try  the  depths  of  its  deep 
waters.  Each  vessel  was  allowed  a  number  of  reels  of  this  twine, 
according  to  her  cruising  ground,  each  reel  containing  ten  thou- 
sand fathoms,  weighing  about  one  hundred  pounds. 

Under  this  order,  Lieutenant  Wm.  Eogers  Taylor,  the  1st  of 
the  Albany,  Captain  Piatt,  commenced  a  series  of  soundings  in 
and  about  the  Gulf  of  Mexico.  Captain  Barron,  of  the  John 
Adams,  ran  a  line  across  the  Atlantic,  and  Caj)tain  Walker,  of  the 
Saratoga,  got  a  cast  in  the  South  Atlantic. 

All  these  soundings  required  verification ;  and  in  1851  the  Dol- 
phin, Lieutenant-commanding  S.  P.  Lee,  was  fitted  out,  under  the 
act  of  1849,  especially  to  assist  me  with  observations  and  experi- 
ments. After  many  trials  and  as  many  failures,  she  at  last  suc- 
ceeded in  getting  good  casts,  which,  being  reliable,  enabled  me  to 
establish  a  law  of  descent  for  the  plummet,  and  so  prove  the 
soundings  of  other  vessels. 

Lieutenant  Lee,  having  thus  "  made  the  egg  stand  on  its  end,"  re- 
turned home,  bringing  with  him  the  best  series  of  deep-sea  sound- 
ings that  up  to  that  time  had  ever  been  made ;  and  they  have  not 
been  surpassed  by  any  up  to  this  day. 

The  Dolphin  was  then  placed  under  the  command  of  Lieuten- 
ant O.  H.  Berryman,  to  continue  this  service.  With  Lee's  plans 
and  experience  to  guide  him,  he  put  to  sea  from  New  York  Octo- 
ber, 1852,  sounding  as  he  went  as  far  as  the  meridian  of  40°  west, 
where  he  was  overtaken  by  a  gale,  damaged,  and  forced  into  the 
Tagus  for  repairs.  Here  he  remained  till  December  19th,  and  then 
returned  home  by  the  southern  route,,  sounding  and  looking  for 
"  vigias"  as  he  came. 

With  Lee's  soundings  in  the  Dolphin,  together  with  those  al- 
ready obtained  from  the  regular  cruisers  in  the  navy,  I  was  ena- 
bled, with  the  assistance  of  Professor  Flye,  to  construct,  in  the  fall 
of  1852,  an  orographic  map  of  the  bed  of  the  North  Atlantic 
Ocean,  and  to  give  a  profile  representing  a  vertical  section  of  its 
bottom  between  this  country  and  Europe  near  the  parallel  of  89° 
north. 


APPENDIX.  355 

The  materials  used  for  tlds  map*  and  profile  were  the  deep-sea 
soundings  already  mentioned  as  made  by  Walsh,  Taylor,eLee,  and 
Barron,  together  with  others  which  had  been  received  from  the 
Congress,  Commodore  M  'Kee ver ;  the  Portsmouth,  Captain  Dornin ; 
the  Cyane,  Captain  Paine ;  the  St.  Louis,  Captain  Ingraham ;  the 
Plymouth,  Captain  Kelly ;  the  Germantown,  Captain  Knight ;  the 
Susquehanna,  Captain  Inman ;  and  Lieutenant  Warley,  of  the 
Jamestown,  Captain  Downing.  These  were  the  first  maps  of  the 
kind  ever  attempted  for  "  blue  water."  Their  object  was  to  show 
the  depressions  of  the  solid  crust  of  our  planet  helow^  as  geographers 
seek  to  represent  its  elevations  above  the  sea-level.f  .  The  "tele- 
graphic plateau"  is  there  delineated  on  Plate  XIY.,  very  much  as 
the  subsequent  deep-sea  soundings  have  shown  it  to  be.  This  at- 
tempt to  map  out  the  bottom  of  the  deep  sea  was  regarded  with 
exceeding  interest  by  the  learned.  Humboldt  gave  it  high  praise ; 
it  0|)ened  the  freshest  and  most  interesting  field  that  remained  to 
him  for  contemplation  in  the  domains  of  science. 

Up  to  this  time,  however,  nothing  had  ever  been  brought  up 
from  the  deep  sea.  The  plummet  was  a  cannon  ball,  and  the 
sounding-line  a  bit  of  small  twine  which  was  broken  off  when  the 
cannon  ball  reached  the  bottom,  so  that  ball  and  twine  remained 
behind ;  consequently  every  cast  of  the  deep-sea  plummet  involved 
the  loss  of  a  shot  and  of  as  much  twine  as  it  took  to  reach  the 
bottom.  It  was  desirable  to  bring  up  soundings,  not  only  that  we 
might  leam  what  the  bottom  and  bed  of  the  ocean  were  made  of, 
but  that  we  might  know  of  a  verity  and  have  the  proof  that  the 
bottom  had  been  reached. 

Under  these  circumstances,  the  attention  of  Lieutenant  J.  M. 
Brooke,  who  was  at  the  time  stationed  at  the  Observatory,  was 
called  to  the  subject,  when  he  made,/??^  hringmg  iq^  specimens  from 
the  hottovij  the  beautiful  and  simple  contrivance  known  as  "Brooke's 
deep-sea  sounding  apparatus." 

When  the  Dolphin  returned  from  the  Tagus,  which  she  did  in 
March,  1853,  arriving  at  Norfolk  on  the  7th  of  that  month,  she  was 
ordered  to  sea  again  under  Berryman,  to  assist  stilh farther  "in 
perfecting  the  discoveries  made  by  Lieutenant  Maury  in  the  course 

*  See  Plates  XIV.  and  XV.,  Maury's  Sailing  Directions,  5tli  edition, 
t  See  p.  239,  240,  oth  ed.  Maury's  Sailing  Directions,  printed  by  C.  Alexander, 
Washington,  and  published  in  February,  1853. 


366  APPENDIX. 

of  his  investigation  of  the  winds  and  currents  of  the  ocean."  And 
that  I  might  procure  specimens  of  the.  bottom,  this  apparatus  of 
Brooke  was  put  on  board  the  Dolphin ;  and  this  was  the  first  time 
that  it  was  put  on  board  any  vessel.  The  first  time  it  was  used 
was  at  1  20  P.M.,  July  7,  1853,  in  latitude  54°  17'  north,  longitude 
22°  33'  west,  by  J."  G.  Mitchell,  then  a  midshipman  on  board  that 
brig.  This  sounding,  as  were  all  since  Lee's  time,  was  made  from 
a  boat;  it  occupied  six  hours.  The  depth  was  2000  fathoms, 
and  the  rod  came  up,  its  arming  loaded  with  precious  trophies. 
This  promising  young  ofiicer  made  every  deep-sea  sounding  that 
was  made  in  the  Dolphin  during  that  cruise,  save  one  only,  and  to 
him  belongs  the  honor  of  bringing  up  the  first  specimen  that  was 
ever  obtained  from  the  bottom  of  the  deep  sea.  Subsequently, 
during  this  cruise,  several  other  specimens  were  obtained ;  but  the 
first  was  described  by  Mitchell  as  "a  fine  chalky  clay." 

The  Dolphin  returned  in  November,  1853.  Her  soundings  dur- 
ing these  two  cruises  with  Brooke's  apparatus  were  first  published 
in  the  sixth  edition  of  Sailing  Directions,  March,  1854.  The  speci- 
mens from  the  bottom  were  forwarded  to  the  Observatory,  and  by 
me  sent  to  that  charming  man  of  science,  the  late  Professor  Bailey, 
of  West  Point,  for  examination  under  his  microscope.  He  exam- 
ined them,  and  found  those  specimens  from  the  bottom  of  the 
great  deep  not  to  have  "a  particle  of  sand  or  gravel  mixed  ivith 
tliemj^  but  to  be  mites  of  sea-shells,  perfect  in  form,  and  as  unworn 
and  untriturated  as  they  were  when  alive. 

This  discovery  of  the  microscope  at  once  suggested  the  idea 
that  there  is  no  running  water,  no  al)rading  forces  at  play  upon 
the  bottom  and  bed  of  the  deep  sea ;  and  consequently  that,  if  an 
electric  cord  were  ever  lodged  upon  the  telegraphic  plateau,  there 
it  would  lie  in  cold  obstru.ction,  without  any  thing  to  fret,  chafe, 
or  wear,  save  alone  the  tooth  of  time. 

Accordingly,  when,  in  February,  1854,  the  projectors  of  the  At- 
lantic Telegraph  inquired  of  me  "  about  the  practicability  of  sub- 
merging the  cable,"  I  was  enabled  to  reply  as  follows : 

"From  Newfoundland  to  Ireland  the  distance  between  the 
nearest  points  is  about  sixteen  hundred  miles,  and  the  bottom  of 
the  sea  between  the  two  places  is  a  plateau,  which  seems  to  have 
been  placed  there  especially  for  the  purpose  of  holding  the  wires 
of  a  submarine  telegraph  and  of  keeping  them  out  of  harm's  way. 


APPENDIX.  367 

It  is  neitlier  too  deep  nor  too  shallow ;  yet  it  is  so  deep  that  the 
wires,  being  once  landed,  will  remain  forever  beyond  the  reach  of 
vessels'  anchors,  icebergs,  and  drift  of  any  kind,  and  so  shallow 
that  the  wires  may  be  readily  lodged  npon  the  bottom. 

"The  depth  of  this  plateau  is  quite  regular,  gradually  increas- 
ing from  the  shores  of  Newfoundland  to  the  depth  of  from  fifteen 
hundred  to  two  thousand  fathoms  as  you  approach  the  other  side. 

"  Whether  it  be  better  to  lead  the  wires  from  Newfoundland  or 
Labrador  is  not  now  the  question ;  nor  do  I  pretend  to  consider 
the  question  as  to  the  possibility  of  finding  a  time  calm  enough, 
the  sea  smooth  enough,  a  wire  long  enough,  and  a  ship  big  enough 
to  carry  and  lay  a  coil  of  wire  1600  miles  in  length.  I  simply  ad- 
dress myself  at  this  time  to  the  question  in  so  far  as  the  bottom 
of  the  sea  is  concerned ;  and  as  for  that,  the  greatest  practical  dif- 
ficulty will,  I  apprehend,  be  found  after  reaching  soundings  at  ei- 
ther end  of  the  line,  and  not  in  the  deep  sea. 

"  A  wire  laid  across  from  either  of  the  above-named  places  on 
this  side  would  pass  to  the  north  of  the  Grand  Banks  and  rest  on 
that  beautiful  plateau  to  which  I  have  alluded,  and  where  the  wa- 
ter of  the  sea  appears  to  be  as  quiet  and  as  completely  at  rest  as 
it  is  at  the  bottom  of  a  mill-pond. 

"Therefore,  so  far  as  the  bottom  of  the  deep  sea  between  New- 
foundland or  the  mouth  of  the  St.  Lawrence  and  Ireland  is  con- 
cerned, the  practicabihty  of  a  submarine  telegTaph  across  the  At- 
lantic is  proved." 

The  letter  from  which  these  extracts  are  taken  is  dated  at  the 
Observatory,  23d  February,  1854,  and  was  addressed  to  Professor 
Morse. 

The  system  of  deep-sea  soundings  thus  inaugurated  has  been 
adopted  by  the  English,  Dutch,  Austrian,  and  all  other  navies 
that  have  since  entered  with  us  in  this  new  field.  From  this  sim- 
ple beginning  and  in  this  short  time  more  knowledge  has  been 
gained  for  man  concerning  the  depths  and  bottom  of  the  ocean 
than  he  had  acquired  in  all  previous  time.  The  English  and 
French  by  their  deep-sea  soundings  have  given  us  materials  for 
orographic  maps  of  the  basins  which  hold  the  Mediterranean 
and  the  Eed  Sea ;  and,  by  order  of  the  Admiralty,  Lieutenant 
Dayman,  of  H.  B.  M.  ship  Cyclops,  ran  last  year  a  beautiful  line 
of  deep-sea  soundings  along  the  telegraphic  plateau.     By  that  ex- 


APPENDIX. 

cellent  wo»k  Lieutenant  Dayman  confirmed  what,  in  February, 
185-i,  I  liacl  told  Professor  Morse  concerning  this  plateau. 

When  the  deep-sea  soundings  came  to  be  studied  under  the 
microscope,  it  was  discovered  that  many  of  these  little  mites  of 
shells  still  retain  in  them  the  fleshy  parts  of  their  inhabitants  when 
alive.  Upon  the  discovery  of  this  fact,  there  was  a  division 
among  philosophers;  some  took  what  is  called  the  '•^hioty  view, 
and  maintained  that  the  presence  in  the  shell  of  the  fleshy  parts 
of  the  animal  was  proof  that  the  bottom  of  the  deep  sea  was  the 
nursery  as  well  as  the  grave  of  these  little  creatures. 

On  the  other  hand,  those  who  took  the  ^^  anti-hiotic'^  view  argued 
that  the  antiseptic  properties  of  the  sea- water  were  sufficient  to 
preserve  the  bodies  of  these  organisms  for  some  time  after  death, 
and  untn  they  had  sunk  far  enough  in  the  depths  below  for  the 
pressure  to  put  an  end  to  decay  by  preventing  that  evolution 
of  gases  which  must  take  place  in  order  that  animal  putrefaction 
may  go  on.  In  proof  of  the  antiseptic  properties  of  sea- water, 
this  school  appealed  to  the  practice  of  the  old  packet  captains, 
who  would  corn  and  restore  tainted  fresh  beef  and  mutton  by 
sinking  it  so  many  fathoms  at  sea,  and  hauling  it  up  nicely  and 
freshly  corned.  The  leaders  of  this  school  also  alluded  to  the  ex- 
perience of  the  whalemen,  which  is,  that  if  a  whale  sinks  at  death 
no  instance  has  been  known  of  his  rising  again  at  sea. 

In  this  stage  of  the  question,  Ehrenberg  of  Berlin  was  examin- 
ing some  deep-sea  soundings  obtained  from  the  bottom  of  the 
Mediterranean,  and  among  them  he  recognized  fresh-water  shells 
with  meat  in  them ! 

This,  in  my  judgment,  proves  the  case  and  settles  the  question, 
though  in  the  ojoinion  of  that  renowned  deep-sea  Biotist  it  neither 
does  the  one  nor  the  other. 

The  chemists,  I  think,  will  show  that  the  pressure  at  the  bottom 
of  the  deep  sea  is  sufficient  to  suppress  all  those  chemical  forces 
which  are  brought  into  play  for  the  evokition  of  gases  during  the 
usual  processes  of  animal  and  vegetable  decay,  and  we  may  con- 
clude that  the  gutta-percha  coating  used  for  insulating  the  con- 
ducting wires  of  the  Atlantic  Telegraph  will  be  preserved  from 
decay  by  the  pressure  of  the  deep  sea  for  an  indefinite  length  of 
time. 

With  this  fact,  we  may,  as  we  roam  through  the  realms  of  con- 


APPENDIX.  309 

jecture,  go  a  step  fartlier  in  tliis  direction,  and  fancy  that  the  sea 
embalms  its  dead — that  all  the  corpses  which,  with  weights  at- 
tached, have  been  committed  to  the  deep  in  blue  water,  are  now 
standing  on  the  bottom,  their  lineaments  and  features  as  perfect  as 
the}^  were  the  day  their  comrades  were  called  to  ''  bury  the  dead.""^ 

This  circumstance  of  the  fresh- water  shells  with  fleshy  matter 
from  the  bottom  of  the  deep  sea  is  one  of  the  most  beautiful  and 
suggestive  facts  that  this  new  system  of  deep-sea' soundings  has 
revealed. 

The  projectors  of  the  Atlantic  Telegraph,  having  acted  upon  the 
information  derived  from  these  researches  concerning  the  bottom 
and  bed  of  the  ocean,  formed  their  company,  and  ordered  their 
cable,  sought  other  information  from  the  Observatory.  I  received 
in  March,  1857,  a  letter  from  Cyrus  "W.  Field,  asking,  in  behalf  of 
the  company,  for  the  best  route  and  time  for  laying  the  cable. 
Considering  the  practical  difi&culties  of  actually  steering  .along  an 
arc  of  such  a  great  circle  as  that  which  passes  through  the  ends 
of  the  Atlantic  cable.  Professor  Hubbard  was  requested  to  com- 
pute the  perimeter  of  a  polygon,  described  in  such  a  manner,  that 
every  side  between  Yalentia"  and  Trinity  Bay  should  be  trisected 
by  the  arc  of  the  great  circle  between  the  two  ends  of  the  cable, 
and  that  a  ship  in  steering  along  this  perimeter  should,  to  pass 
from  one  side  to  the  next,  have  to  change  her  course  but  the  quar- 
ter of  a  point.  Thus  a  polygonal  route  was  given  by  which  each 
ship,  by  increasing  her  great-circle  distance  only  three  hundred 
and  fifty  fathoms,  and  changing  her  course  only  six  times  after 
joining  cables,  would  be  enabled  to  reach  her  port  by  steering 
straight  courses.  Lieutenant  AiUick  j^rojected  in  duplicate  the 
sides  of  this  polygon  on  charts,  which  were  sent  to  the  company 
for  the  paying-out  vessels  to  steer  by. 

Lieutenant  Bennett  was  called  on  to  assist  in  the  investigations 

*  When  a  person  dies  on  board  of  a  man-of-war,  and  is  to  be  buried  at  sea,  his 
body  is  sewed  np  in  his  hammock,  witli  one  or  two  cannon  balls  secm-ed  to  his  feet. 
When  it  is  ready  for  the  burial,  it  is  placed  on  a  plank  at  the  gangway,  and  all 
hands  are  mustered  on  deck  by  the  boatswain's  call  to  "bury  the  dead."  After 
reading  the  burial  service,  the  plank  is  tilted,  and  the  body  slides  off,  feet  foremost, 
into  the  sea.  In  this  position  the  body  sinks,  in  this  position  it  reaches  the  bottom, 
and  in  this  position  it  may  remain,  beyond  the  reach  of  decay,  a  perfect  human  form 
for  ages. 


370  APPENDIX. 

necessary  to  enable  me  to  answer  the  question  as  to  tlie  best  time 
for  laying  tlie  cable.  For  this  the  results  of  260,000  days  of  ob- 
servation at  sea  were  consulted,  and,  after  a  laborious  investiga- 
tion, the  company  was  informed  of  the  result,  which  was  that  the 
"most  propitious  time  for  their  undertaking  was  the  last  of  July 
and  the  first  of  August,"  and  that  "the  steamer  with  the  western 
end  of  the  telegraphic  cord  on  board  would  be  less  liable  than  the 
other  to  encounter  a  gale."  This  proved  true ;  for  the  Agamem- 
non came  near  losing  her  end  of  the  cable,  owing  to  the  violence 
of  wind  and  waves,  while  the  Niagara  was  sailing,  with  the  west- 
ern end,  in  smooth  water  and  a  tranquil  sea;  and  it  also  turned 
out  that  "between  the  20th  of  July  and  10th  of  August"  was  the 
time  which  proved  the  best,  as  the  company  had  been  informed  it 
would. 

The  investigations  concerning  the  physics  of  the  sea  go  farther, 
and  warrant  other  conclusions  of  much  importance  touching  the 
future  progress  of  submarine  telegraphy.  They  satisfy  me  that 
no  sea  is  so  deep  or  so  stormy  but  that  an  electric  cord  may  be 
safely  planted  in  the  still  waters  of  the  bottom ;  that  the  currents 
and  storms  which  agitate  the  surface  do  not  reach  far  down  into 
the  depths  below ;  that  under  the  pressure  of  the  deep  sea  there 
is  no  decay :  even  those  mites  of  little  animals  that  inhabited, 
when  alive,  those  microscopic  shells  which  Brooke's  rod  brought 
up  from  the  bottom  for  us  are,  there  is  ground  to  conjecture,  pre- 
served for  ages  down  there — whence  it  may  be  inferred  that  sub- 
marine cables  will  last  lifetimes  at  the  bottom  of  the  deep  sea ; 
that  henceforward  wrappings  of  iron  wire  about  submarine  cables 
for  the  deep  sea  may  be  dispensed  with;  that,  except  for  shoal 
water,  no  future  cable  need  be  larger  than  the  gutta-percha  cord 
which  incases  and  isolates  the  conducting  wire  of  the  Atlantic 
Telegraph ;  and  that  submarine  lines  of  telegraph,  though  their 
prime  cost  may  be  a  little,  but  not  much  more  than  that  of  over- 
land lines,  will  henceforth  prove  the  cheaper  in  the  end ;  for, 
being  once  down,  they  will  require  no  repairs  in  the  deep  sea. 
Only  as  they  come  from  the  depths  of  the  ocean  to  the  land  will 
they  be  liable  to  injury.   - 

October,  1858. 

THE  END. 


I'li.o-j-  SIN': in 


i  nJr     I 


™ 


Plate  V: 
iL'i)  ]■:. 

I! 

,:  ■JO'X,>mi 


W 


SM 


,ifl?ji  III 


w  mi  II 
25  G 


U£- 


Oct\Xov. 


wiior 


H 


149 


Id'XtntJi 


lO'-MvtJt 


\ 


TT 


H 


P — ^ r; 

!       i       I 


t 


o'Xflitfi 


Uo'E. 


11  .\ri'l, //.„:, i 


,7  •/./•■  STIiJi.lM  .i.V/J  JI/I//:T 


: 

Vi-i^ 

^          ^ 

\ 

,« .,„  4»  .f 

-!|.f 

|-~-r  --- 

1  M-         -f 

iHiiT 

'  '   1            ' 

,^>^ 


.^^^-C<- 


fii?>F■•i^,r'^''ry*^''J*^^**°^^  ^'''^'^^^■^^'^'~-^^^^^5?-^r-<-l^''^~%--3r-  ■"C^^"'^  ^  ^"-^ 


l^'- 


r«-T-^ 


^■^r 


IJryJfij-  TtfJ:''f'}fOM 


■    1/  ^-^ 


^.^ 


■w--mm^ 


VKPTli'AL    ^•F.(■TION NORTH    ATLANTIC 


/i'l.w/i  cf///,- yo/f// . I//, ,/,_/,,  i",Y, 


J'/'<h  .\/ 


VERTICAL    SECTION NORTH 


STOn^fS  .UVD  RAINS  11^ 2^0 JITHANV  SOUTH ATL.LVTJC 

f  West  In^es  not  induAA.) 


1 1  j'p  ?  U  111  5  M  ^^  ^' 


4  44  t  ^  I'  -I  I  1 1  M  ^  I  *  ^'  H  4 1  i  i  M  4  1 4- 1  M  i  I  1 1  >  M  1 1  t  TXt 


1  j  1 


^'  ^-  > 


I  n'  > 


1^