March  4,  1897. 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
187 
minerals  would  form  a  soil  rich  in  potash  but  poor  in  limp,  while 
the  last  named  would  form  a  soil  poor  in  potash  but  rich  in  lime. 
By  the  action  of  the  disintegrating  agents,  which  we  shall 
consider  when  dealing  with  the  formation  of  soils,  the  exposed 
surface  of  the  crystalline  rocks  was  broken  down,  and  the  loosened 
particles  were  carried  by  rivers  into  the  sea,  where  they  settled 
down  to  form  sedimentary  rocks.  We  have  therefore  two  classes 
of  rocks — namely,  the  primary,  formed  by  the  action  of  fire,  and 
known  as  igneous  (Lat.,  ignis,  fire)  ;  and  the  sedimentary,  formed 
by  the  action  of  water,  and  called  aqueous  (Lat.,  aqua,  water). 
Another  very  important  class  of  rocks,  formed  after  those  just 
named,  are  the  limestones  and  peat  beds.  The  limestone  rock# 
were  formed  by  the  deposition  of  shells  and  other  calcareous 
matter  in  the  ocean,  and  the  peat  beds  were  formed  by  the  accumu¬ 
lation  of  vegetable  matter  in  wet  situations. 
The  sedimentary  rocks,  after  being  under  water  for  thousands 
of  years,  were  raised  and  became  dry  land.  All  the  exposed  parts 
of  rocks  are  constantly  being  attacked  by  the  various  disintegrating 
agents  which  pulverised  them,  and  the  material  thus  formed  may 
be  looked  upon  as  rotted  rock  or  soil.  Soil,  then,  is  the  name  given 
to  the  more  or  less  powdery  substance  which  we  find  covering  the 
surface  of  rocks. 
On  page  91  a  correspondent  signing  himielf  “  Henri  ”  calls  my 
attention  to  a  paragraph  on  page  47,  which  he  says  “  seems  wrong.” 
The  portion  referred  to  is  as  follows: — “During  growth  certain 
chemical  changes  are  taking  place  during  which  oxygen  is  absorbed 
and  carbon  dioxide  is  exhaled.”  Your  correspondent,  after  quoting 
the  above  passage,  asks  two  questions — viz  ,  “  (1)  Is  it  so  ?  and  (2) 
Should  it  not  be,  Carbon  dioxide  is  absorbed  and  oxygen  exhaled  ?” 
To  the  first  question  I  answer,  Yes  ;  to  the  second,  No. 
By  again  turning  to  page  47  your  correspondent  will  find  that 
I  say  in  the  next  sentence  to  the  one  which  appears  to  him  to  be 
wrong,  “  This  interchange  of  gases  is  called  the  ‘  respiration  ’  of 
plants.”  Plants  also  absorb  carbon  dioxide  (C02)  from  the  atmo¬ 
sphere,  and,  under  the  influence  of  sunlight  and  the  cbloropla9tids, 
this  gas  is  broken  up,  the  carbon  being  retained  and  the  oxygen 
exhaled.  This  interchange  of  gases  is  known  as  the  “  assimilation  ” 
of  plants,  a  subject  which  will  be  subsequently  dealt  with. 
Now,  my  friend,  again  take  up  your  “  Oliver’s  Botany,”  and  see 
what  he  says  about  the  respiration  of  plants,  and  I  think  you  will 
find  that  the  statement  on  page  47  is  perfectly  correct. — W.  Dyke. 
A  GARDEN  IN  THE  ISLE  OF  WIGHT. 
[An  Address  (amplified)  by  Rev.  H.  Ewb.vnk  to  the  members  of  the 
Horticultural  Association  at  Newport.] 
(i Continued  from  page  141.) 
It  has  been  such  an  absurd  attempt  on  my  part  to  give  representa¬ 
tive  flowers  for  the  different  seasons  of  the  year  that  I  feel  I  must  now 
withdraw  from  it  altogether.  Time  and  space  are  against  me,  and  the 
Eremuri,  the  Calochorti  and  Ixias  must  not  be  offended  if  they  are 
passed  over  in  silence.  I  only  wish  to  say  a  word  about  rock  plants, 
for  they  have  a  great  attraction  of  their  own.  It  i#  wonderful  that 
they  succeed  as  well  as  they  do  when  we  consider  how  different  are  the 
conditions  under  which  they  grow  naturally  from  those  under  which 
they  are  here.  In  Switzerland  and  other  countries  they  are  buried 
deeply  in  snow  for  many  months  of  the  year,  and  then  they  are  exposed 
from  June  onwards  to  most  brilliant  sunshine  and  long  s' retches  of 
settled  glorious  weather.  Here  in  England  they  arwteased  by  snatches 
of  fine  weather,  which  make  them  grow  prematurely,  and  at  the  wrong 
time  of  the  year,  and  then  all  of  a  sudden  frost  and  snow  come  on  them  in 
an  utterly  unprotected  condition,  and  they  have  first  one  thing  and  then 
another  against  them  all  the  year  round.  It  is  in  summer  often  worse 
for  them  than  in  winter,  for  the  sun  has  a  power  here  which  some  of 
them  are  scarcely  able  to  resist. 
Still  they  get  on  somehow,  as  I  have  said  just  now,  for  there  is  a 
wonderful  power  of  accommodation  in  plants,  and  they  prosper  far  better 
than  one  could  have  thought  of  before  the  trial  was  made.  In  one  way 
and  the  other  I  must  have  5000  plants  in  my  rockery,  according  to  a 
computation  which  my  gardener  and  I  made  a  short  time  ago,  for  it  is 
impossible  to  tell  with  certainty  about  it. 
A  condition  for  success  is  that  the  roots  should  run  back  a  very  long 
way,  and  derive  sustenance  from  hidden  stores  of  nutriment  which  are  far 
away  out  of  sight.  Thus  a  plant  1  inch  high  will  go  forty  times  deeper 
than  it  will  venture  to  appear  above  ground,  and  when  you  wonder  how 
such  a  gem  as  Eritrichium  nanum  in  Switzerland,  or  elsewhere,  can 
stand  the  summer  sun,  it  is  sometimes  forgotten  that  it  draws  upon 
hidden  stores  of  food  by  its  long  and  tiny  rootlets.  Then,  again, 
Btones  on  the  mountain  sides,  and  the  debris  of  ages  prevent  evapora¬ 
tion.  The  state  of  things  in  England  during  the  summer  is  often  very 
much  dried  up,  and  mischief  must  sometimes  be  prevented  by  a  mulch  of 
leaf  mould  and  silver  sand,  and  by  a  coating  of  small  stones,  which  does 
great  good. 
Very  often  it  is  good  practice  to  grow  a  plant  in  a  horizontal  position, 
It  sends  the  water  off  the  foliage,  and  keeps  it  from  rotting  better  than 
anything  else  can  do  it.  Thus  Lithospermum  graminif  olium  and  Ramondia 
pyrenaica  (fig.  40)  submit  to  treatment  of  this  sort,  as  may  be  seen 
in  Kew  Gardens  with  Ramondia,  and  there  is  great  gain  from  it.  But, 
of  course,  the  first  thing  in  growing  alpines  is  to  consider  what  sort  of 
home  you  can  give  them,  and  this  is  a  matter  which  involves  considera¬ 
tions  of  taste,  and  also  of  space  and  money.  There  are  two  kinds  of 
rockeries  in  this  country,  and  none  other  need  be  considered.  One  is 
where  everything  is  made  to  give  way  to  the  appearance  of  the  rockery 
itself,  and  a  miniature  Mount  Blanc  or  Monte  Rosa  is  contemplated,  and 
this  let  me  say  is  for  the  most  part  very  expensive,  and  whensoever  it  is 
badly  done  it  can  be  very  cockney  fled.  It  also  takes  a  great  deal  of 
room  to  carry  it  out  at  all  with  effect. 
The  other  way,  and  it  is  that  which  I  exclusively  advocate  myself,  is 
to  give  up  all  ambitious  projects  entirely,  and  to  consider  not  what  you 
think  good  and  beautiful  yourself  in  the  way  of  a  rockery,  but  what  the 
plants  themselves  would  like,  and  how  best  they  are  to  be  treated.  The 
FIG.  40. — RAMONDIA  PYRENAICA. 
sort  of  rockery  which  I  allude  to  is  something  in  the  way  of  that  which 
obtains  in  the  Boyal  Botanic  Gardens  in  Edinburgh.  It  is  in  no  sense 
whatever  an  imitation  of  a  mountain  range,  but  it  is  a  good  and  fitting 
receptacle  for  plants,  and  that  is  all  that  is  wanted.  My  rockery  looks 
more  like  an  old  crumbling  ruin  than  anything  else,  and  visitors  have 
often  compared  it  with  an  old  Roman  amphitheatre,  which  it  does  in  a 
way  resemble. 
The  advantages  are  these  A  construction  such  as  mine  costs  a 
great  deal  less  than  an  artistic  rockery.  From  first  to  last  I  do  not 
suppose  that  I  have  spent  more  than  £40  or  £50  on  it,  whereas  thousands 
can  be  easily  poured  out  in  the  other  way  of  making  mountains  to  order. 
I  have  innumerable  little  square  pockets  here  into  which  the  plants 
lovingly  nestle,  and  where  they  can  be  watered  with  effect,  which  is  a 
very  great  point  in  summer  time,  and  on  this  account  they  prefer  level 
spaces  to  an  inclined  plane.  Moreover,  there  are  a  great  variety  of 
aspects,  and  shade  is  more  easily  procured  than  in  any  other  way  ;  and 
also  the  differences  of  taste  in  the  way  of  soil  can  be  accounted  for.  It 
is  true  that  before  it  was  properly  clothed  the  whole  thing  looked  very 
bare  and  unsightly,  and  many  hard  things  were  then  said  of  it ;  but 
that  is  not  at  all  the  case  now,  when  results  have  declared  themselves. 
