TTIK  TROPICAL  AGRICULTURIST. 
March 
ism,  though,  when  they  ate  viewea  in  the  light 
of  the  true  religion,  they  are  very  much  to  be 
deplorea,  are  often  possessed  of  much  social  and 
political  value. 
It  is  at  all  even's  certain  that  the  way  in  which 
the  inhabitants  of  the  finest  couutries  on  the  surface 
of  our  globe  tend  to  bring  upon  themselves  the 
gratest  calamities,  is  by  the  thoughtless  destruction 
of  the  forest,  first  around  their  dwellings,  then  all 
^ country.  For  a few  generations  at  first, 
indeed,  the  felling  of  the  forest  is  a triumph  over 
nature,  for  ground  that  bears  grain  or  annual  crops 
of  some  kind,  is  alv\ays  more  convenient  than 
ground  that  bears  trees,  however  nutritious  or  de- 
licious their  fruit.  But  when  the  custom  of  wood- 
cutting has  once  been  established  in  a community, 
and  the  necessity  of  more  and  more  firewood  and 
more  and  more  material  for  building,  as  also  of  new 
clearings  for  the  sake  of  obtaining  a virgin  soil  in- 
creases with  the  increase  of  the  population,  the 
process  of  felling  tends  to  go  on  too  far — even  till 
the  whole  accessible  country  is  denuded  of  its  for.  st, 
and  the  soil  is  laid  permanently  bare  to  the  impact 
of  the  sunbeams.  Now  of  this  the  consequences 
are  most  injurious.  In  the  first  place  the  rainfall 
is  proportionally  diminished.  And  though,  as  wo 
know  in  Scotland,  there  are  some  countries  where 
this  would  be  an  improvement,  yet  in  reference  to 
all  intertropical  countries,  and  indeed  the  surface 
of  our  planet  generally,  it  is  an  evil.  And  in  the 
second  place,  the  soil,  when  stript  of  the  clothing 
which  the  forest  afforded,  and  exposed  naked  to  the 
heat  of  the  sunbeam,  changes  very  rapidly  from 
the  rich  mould  which  the  long-continued  fall  of  the 
leaf  in  the  forest  had  made  it.  and  becomes  very 
unproductive.  Had  occasional  trees  in  the  forest 
been  loft  to  give  shade  during  part  of  the  day.  the 
destination  of  the  carbon  in  the  mould  would  have 
been  to  be  slowly  converted  into  carbonic  acid,  and 
so  to  supply  food  to  the  successive  crops  growing 
on  the  soil  as  they  required  it.  But  when  the  sun- 
beam is  left  free  to  break  in  its  full  force  on  the 
soil  all  day  long,  it  burns  the  carbon  in  the  soil 
with  great  rapidity  into  carbonic  acid.  Aud  this 
gas,  unless  there  be  in  the  soil  some  oxide  having 
afifinity  for  it  to  retain  it,  goes  off  as  gas,  injuring 
the  salubrity  of  the  air  perhaps,  and  at  all  events 
wholly  impoverishing  the  soil ; for  carbonic  acid  is 
the  principal  food  of  all  plants.  The  same  course 
of  things,  it  might  be  shown,  happens  with  regard 
to  ammonia  ; and  thus,  both  as  itself  the  immediate 
food  of  plants,  and  as  that  which  by  oxidation 
yields  nitre,  ammonia  is  lost.  Thus  the  indiscirmiuate 
destruction  of  forest  over  any  great  breadth  of  coun- 
try, if  that  country  have  plenty  of  sunshine,  is  a 
great  evil. 
This  is  not  mere  theory.  There  is,  on  the  con- 
trary, good  reason  for  believing  that  the  view  now 
given  explains,  to  a great  extent,  the  character  of 
the  surface  and  climate  of  all  the  old  inhabited 
regions  of  our  planet  in  the  present  epoch  of  the 
world.  And  what  invests  the  subject  with  interest 
is  this,  that  while  it  explains  the  cause  oi  certain 
great  evils  which  prevail  very  widely,  it  also  sug- 
gests a cure  for  them.  Thus,  not  only  is  the  great 
breadth  of  Africa  and  Australia,  in  consequence  of 
aridity,  unfit  for  being  the  dwelling-place  of  civilized 
man,  but  Western  Asia,  and  even  the  valleys  of 
the  Ganges,  the  Jumna,  and  the  Indus,  are  greatly 
at  fault  in  this  respect.  Now,  of  the  former  regions 
in  former  times  we  can  say  nothing  for  cer- 
tain, because  nothing  of  their  early  history  is 
known.  But  with  regard  to  those  Asiatic  regions 
which  have  been  named,  their  ancient  history  is 
known.  There  can  be  no  doubt  that,  in  ancient 
times,  they  were  more  densely  peopled,  aud  that 
by  races  far  more  energetic  than  their  present 
inhabitants.  There  can  be  no  doubt  that  their 
climates  were  more  genial  .and  their  soils  more 
fertile  then  than  they  are  now.  And  why  tlie 
difference V It  is  due,  I believe,  to  the  thougtless 
destruction  of  the  forest,  with  which  nature  ever 
tends  to  clothe  the  entire  surface  of  our  planet, 
BO  far  as  it  is  possible  for  her  to  do  so.  Hence 
in  the  present  age  a great  decrease  in  the  annual 
rainfall,  and  its  confinement  to  certain  seasons  do 
pending  on  celestial,  not  terrestrial,  influences,  instead 
of  a more  uiiifmm  distribution  over  all  the  year. 
Hence  a comparaiatively  rapid  combustion  of  the 
soil  by  the  sunbeam,  and  the  loss  of  the  fertility 
imparted  to  it  by  the  virgin  forest  now  no  more. 
But  why,  it  may  be  asked,  press  this  theory  ? 
It  is  only  a speculation,  And  granting  that  it  is 
true,  what  can  be  made  of  it  ? To  this  the  answer 
is,  that  it  proclaims  aloud  to  the  philanthropic 
traveller,  colonist,  planter,  soldier,  and  to  any 
government  in  charge  of  such  bare  and  desolated 
territories  as  have  boen  described,  to  do  all  they 
can  to  encourage  arboriculture  to  the  utmost  in 
then-  power,  aud  to  call  for  the  restoration  of  the 
forest. 
In  reference  to  many  at  present  inhospitable  lands, 
there  is  no  saying  what  benignant  results  might 
be  effected  in  the  course  of  even  a few  generations, 
if  only  trees  could  be  stolen  upon  them,  and  ulti- 
mately established  in  such  clumps,  belts  and  breadths 
as  might  be  required.  With  regard  to  Western 
Asia  and  Africa,  indeed,  the  case,  in  consequence 
of  the  characters  of  the  governments  which  rule 
there,  may  be  hopeless  in  the  present  generation. 
But  something  might,  perhaps,  be  begun  to  be  done 
even  now  for  the  valleys  of  the  Ganges  and  Jumna 
and  their  tributaries,  and  for  those  of  the  rivers 
of  the  Punjaub,  and  for  Australia,  which  are  all 
more  or  less  under  our  own  control. 
But  can  nothing  be  done  nearer  home  ? Is  our 
own  much-loved  country  all  right  as  to  arboriculture  ? 
In  answer  to  this  it  may  be  said,  that  it  is  at 
least  very  pleasing  to  consider  what  has  been  done. 
When  the  J.’.mperor  of  the  French  was  contemplating 
to  do  somethiug  for  lUexico,  ho  appointed  one  of 
the  most  learned  men  of  sience  in  France  to  give 
him  in  a report  as  to  different  nations,  showing 
what  nature  bad  done  for  each  of  them,  aud  what 
man  had  done.  The  result  was,  if  I remember 
rightly,  that  of  thirty  which  were  compared,  ycotland 
stood  second  as  to  what  man  had  done  for  her, 
but  lowest  and  last  as  to  what  nature  had  done 
for  her;  while  as  to  Mexico,  its  position  was  as 
nearly  the  very  reverse.  Admirable,  therefore,  is 
that  which  man  has  done  for  Scotland  already. 
But  from  what  has  been  advanced,  with  regard 
to  other  contries,  the  question  may  be  lejitimately 
asked  here.  Has  our  country,  too,  been  denuded  of 
its  primeval  forest  by  the  unreflecting  hand  of 
mau  ? Now,  to  this  the  answer  is,  that  in  our  lati- 
tudes the  hand  of  man  is  not  required  for  that  work. 
Where  the  temperature  in  the  shade  never  rises 
high,  the  vegetable  remains  resulting  from  the  fall 
of  the  leaf,  instead  of  decomposing  too  rapidly,  as 
they  tend  to  do  in  tropical  couutries,  scarcely  decom- 
pose at  all.  On  the  contrary,  the  mould  tends  to 
give  birth  to  certain  chemical  substances,  such  as 
tannin,  aud  especially  gallic  acid,  humic  acid,  Ac., 
which  are  not  only  themselves  not  decomposable  in 
ordinary  course,  but  which  preserve  from  decom- 
position the  mould-molecules  with  which  they  are 
mixed.  Hence  the  stratum  immediately  under  the 
trees  continually  increases  in  thickness  from  age 
to  age.  Now,  like  other  insoluble  media,  this  sour 
soil  is  no  food  for  tho  trees  growing  upon  it.  They 
spread  out  and  send  up  to  the  surface  the  spongioles 
of  their  roots  in  vain.  If  they  receive  anything, 
it  is  only  poison  instea  I of  food.  Aud  thus  it  comes 
to  pass  that  ultimately  the  forest  fails  of  its  own 
accord;  and  its  only  recorders  are  the  noble  shafts 
of  trees  found  prostrate  in  the  moss  when  that 
moss  happens  to  be  cut  into. 
Tlie  state  of  the  elements  which  produces  this 
result  extends  over  Europe  for  a bieadth  < f about 
three  degrees  of  latitude.  In  some  regions,  however, 
it  is  not  so  inimical  to  nature's  determination  to- 
wards arboriculture,  but  that  where  one  forest  has 
fallen  she  succeeds  m rearing  another  spontaneously 
of  a different  kind  on  the  same  area.  Thus  archroo- 
logists,  in  their  recent  rosearchos  into  tho  antiquity 
of  man,  have  brought  to  light  by  their  diggings 
that  Denmark,  in  successive  epochs,  has  been  clothed 
liy  three  successive  forests, — first  of  pine,  then  of 
oak,  and  now  of  beech.  But  to  accomplish  such  an 
