20 
On  the  Climate  of  the  British  Islands 
1817,  a large  continent  of  ice  on  tlie  north  of  Iceland,  having  an 
area  of  many  thousand  square  miles,  was  suddenly  broken  up,  and 
carried  by  the  current  southward  into  the  Atlantic,  where  im- 
mense quantities  were  found  on  the  south-east  of  Newfoundland, 
none  of  which  drifted  nearer  the  British  shores  than  the  32°  of 
longitude.  In  1841,  the  Great  Western  steamer,  in  her  voyage 
to  New  York,  encountered  a field  of  ice  extending  100  miles  in 
one  direction,  surrounded  by  innumerable  floes  and  bergs. 
A large  proportion  of  the  ice  brought  southward  by  the  Arctic 
current  is  in  the  form  of  immense  icebergs,  which  have  their 
birth  on  the  shores  of  Spitzbergen  and  Greenland.  The  hills  of 
“Plutonic”  rock  along  the  sea-coast  have  their  elevated  and  in- 
clined valleys  filled  with  enormous  glaciers,  which,  by  a gradual 
but  sure  process,  travel  onward  to  the  sea,  and  are  ultimately 
broken  off  and  set  afloat  as  icebergs.  Captain  Parry  measured 
a berg  in  Baffin’s  Bay  4169  yards  long,  3869  yards  wide,  and 
51  feet  high,  being  aground  in  61  fathoms  of  water.  An  iceberg 
examined  by  Captain  Graah  on  the  east  coast  of  Greenland,  rose 
120  feet  out  of  the  water,  and  its  solid  contents  were  estimated 
to  be  upwards  of  900,000,000  cubic  feet.  Icebergs  are  often 
so  numerous  that  Captain  Scoresby  counted  500  from  one  point 
of  view. 
50.  The  northern  origin  of  the  Arctic  current,  and  the  ice 
with  which  it  is  continually  loaded,  give  it  a temperature  of  16° 
or  18°  below  that  of  the  adjoining  ocean ; and  at  its  southern 
termination  on  the  great  bank  of  Newfoundland,  the  water  is  25° 
colder  than  the  contiguous  sea,  and  33°  lower  than  the  Gulf- 
stream,  with  which  at  this  point  it  comes  in  contact. 
The  cold  surface  of  the  water  and  the  exposed  parts  of  the  ice 
materially  affect  the  surrounding  air.  On  ships  approaching  an 
iceberg,  the  thermometer  falls  15  or  20  degrees.  A good  illus- 
tration of  this  fact  is  afforded  by  the  different  amount  of  heat  on 
the  north  and  south  coasts  of  Iceland — the  Polar  current  flowing 
along  the  north,  and  some  of  the  warm  drift-water  of  the  Atlantic 
reaching  the  south  coast.  Here,  in  a distance  of  100  miles,  the 
difference  of  mean  temperature  is  8°. 
51.  The  distance  between  the  southern  extent  of  the  ice  in  the 
North  Sea  in  summer  and  winter  is  about  140  miles,  and  that 
along  a margin  of  900  miles : thus  on  an  average  of  ) ears  126,000 
square  miles  of  ice  are  broken  up  each  summer  from  this  part  of 
the  sea,  and  drifted  southward  into  the  Atlantic,  where  it  is  caught 
by  the  current  which  has  been  described,  and  swept  to  the  shores 
of  Greenland  and  America.  Now  let  us  suppose  that  this  current, 
instead  of  protecting  the  British  Isles,  flowed  southward  from 
Spitzbergen  along  the  coast  of  Norway.  It  would  convert  Scot- 
land into  another  Labrador,  and  her  skilful  agriculturists  into  seal- 
