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JOURNAL  OF  HORTICULTURE  AND 
CO  TTA  GE  GARDENER. 
October  16,  1902. 
those  grown  in  pots.  The  treatment  is  of  the  simplest.  Place 
the  Hyacinths  upon  the  glasses  containing  sufficient  water  to 
touch  the  base  df  the  bulbs,  and  keep  them  in  a  cool,  dark 
position  until  growth  has  become  active,  .when  they  may  bo 
brought  to  the  light  of  a  window.  The  water  in  the  vases  will 
need  replenishing  from  time  to  time,  and  the  flower-spikes  will 
need  support. 
Sound  bulbs,  rich,  light  soil  of  an  open  sandy  nature,  with  an 
absence  of  unduly  hard  forcing,  and  giving  ample  time  for  roots 
to  form  in  the  plunging  bed ;  here  you  have  all  the  secrets  (which 
are  very  open  ones)  there  are  in  connection  with  the  successful 
treatment  of  many  of  the  charming  and  beautiful  things  which 
come  under  tbe  category  of  bulbs. — J.  W.,  Newent. 
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I 
Hot  Water  Boilers. 
Mr.  Louis  Pearson  (of  Beeston)  recently  read  before  the  Insti¬ 
tute  of  Heating  Engineers  a  paper  on  “  Hot  Water  Boilers,” 
in  which  there  are  several  practical  hints  to  those  interested  in 
•horticultural  work.  Mr.  Pearson  shows  that  old  cast  iron  boilers 
.were  both  economical  and  efficient,  but  they  were  discarded  on 
account  of  their  faulty  jointing  and  unequal  thickness  of  metal, 
both  of  which  defects  have  now  been  overcome  in  the  modern 
boilers.  He  prefers  cast  iron  boilers  to  those  wrought  in  iron  and 
steel,  as  the  iron  boilers  can  be  made  in  'sections,  which 
enable  them  to  be  fixed  in  positions  where  wrought  boilers  could 
not;  be ;  it  also  enables  the  firebox  to  be  made  in  deeply  corru¬ 
gated  or  tubular  forms,  which  not  only  present  a  much  larger 
surface  to  the  direct  action  of  the  fire,  but  also  tends  to  check  the 
flow  of  gases  and  mix  them  thoroughly  with  the  oxygen,  thereby 
causing  better  combustion  and  economising  fuel.  '  Cast  iron  is 
also  much  less  affected  by  oxydisation,  which  is  a  great  consideraf- 
tion  in  our  climate.  Also  experiments  made  by  the  Philadelphia 
Scientific  Institute  show  that  as  a  transmitter  of  heat,  cast  iron 
is  more  efficacious  than  wrought  by  over  10  per  cent , 
However,  the  chief  reason  for  the  greater  economy  of  cast 
boilers  is  due  to  the  corrugations  and  the  tubes  that  can  be  readily 
and  cheaply  placed  in  the  firebox,  which  not  only  add  very  largely 
to  the  direct  heating  surface,  but  break  up  and  thoroughly  mix 
the  gases  as  they  leave  the  firebox,  causing  a  better  combustion. 
Ihe  matter  of  combustion  should  be  fully  considered  before  design¬ 
ing  a  boiler  of  any  description  or  criticising  those  already  made. 
Heat  is  caused  by  the  chemical  union  of  various  elements,  and  as 
there  is  only  one  part  of  oxygen  to  four  parts  of  nitrogen  in  the 
atmosphere,  we  see  the  necessity  of  introducing  a  large  amount 
of  air  to  insure  perfect  combustion.  Mr.  H.  J.  Mills,  in  his 
treatise  on  boilers,  puts  the  amount  of  air  required  to  consume 
one  ton  of  coal  perfectly  at  120,000  cubic  feet.  It  will  be  seen 
from  the  foregoing  remarks  the  reason  for  a  thin  fire  giving  a 
much  better  result  than  a  thick  one. 
As  a  rule  it  is  safe  to  say  that  the  smaller  the  fuel  the  thinner 
the  fire  should  be,  and  the  larger  the  fuel  the  thicker,  on  account 
of  the  larger  interstices  in  the  use  of  the  latter.  It  is  a  common 
practice. to  leave  the  fire  door  open  for  a  short  time  after  firing, 
to  consume  the  smoke;  this,  cf  course,  is  wrong,  for  though  you 
get  a  large  supply  of  oxygen,  yet,  as  it  is  at  a  low  temperature,  it 
does  not  therefore  combine  properly  with  the  gases.  The  boiler, 
too,  is  being  cooled  instead  of  heated,  and  in  the  case  of  wrought 
iron  or  steel,  it  also  proves  injurious  to-  the  plates.  Damp  boiler 
boles  are  often  a  source  of  considerable  trouble  to  both  heating 
engineers  and  their  clients,  and  most  of  the  trouble  is  caused  by 
engineers  trying  to  keep  water  out  of  stokeholes  built’ with' flat 
sides  and  bottom,  by  merely  laying  the  bricks  in  cement,  or  lining 
with  ^  al  d©  1  ravers,  without  considering  the  pressure.  This  is 
very  considerable,  for  the  total  amount  of  a  boiler  house  floor, 
loft  by  10ft  by  5ft  deep,  supposing  the  subsoil  water  to  be  level 
with  the  top  of  the  brickwork,  is  54,0001b  or  nearly  25  tons  It 
is,  therefore,  quite  apparent  that  this  must  be  ‘provided  for. 
V\  ith  small,  medium-sized  boilers  the  simplest  and  best  way  is  to 
place  the  boiler  m  a  wrought  iron  tank,  which  should  be  well 
tarred,  inside  and  out,  and  paved  with  blue  bricks.  Where  the 
boiler  is  very  large,  there  should  be  an  inverted  arch  built  under 
the  floor  of  the  stokehole  and  tied  to  the  Avails,  which  should  be 
at  least  14m,  and  have  an  inch  space  left  between  the  4 Jin  and  9in 
\vqrk,  to  be  afterwards  filled  with  Val  de  Travers.  Even  with 
this  plan  the  workmanship  and  material  must  be  of  the  best  to 
ensure  success. 
An  American  Forestry  Magazine. 
Arrangements  have  been  made  for  the  publication  of  the 
“  Magazine  of  Arboriculture  ”  as  the  official  organ  of  the  Inter¬ 
national  Society  of  Arboriculture,  and  will  have  as  its  distinctive 
purpose  forest  perpetuation.  The  secretary  of  the  society  J  P 
Brown,  Connorsville,  Ind.,  will  act  as  Editor.  The  society 
claims  the  credit  of  having  induced  the  p'anting  of  over 
1,000,000  trees.  ° 
Hardy  Peat-Loving  Shrubs. 
A  large  proportion  of  the  hardy  shrubs  which  require  soil 
free  from  lime,  and  prefer  that  of  a  peaty  nature  for  then- 
successful  cultivation  belong  to  the  great  family  Ericaceae, 
and  are  characterised  by  their  compact  habit,  beautiful 
flowers,  and  suitability  for  small  gardens.  With  the  excep¬ 
tion  of  the  stronger  growing  species  of  Arbutus  and 
Rhododendron,  very  few  grow  more  than  5ft  or  6ft  high, 
while  quite  a  large  number  make  carpet-like  masses  of  less 
than  a  foot  in  height.  A  peculiarity  of  the  family  is  the 
number  of  genera  it  contains,  Avhich  are  made  up  almost 
entirely  of  ornamental  species,  Erica  and  Rhododendron 
being  cases  in  point. 
A  small  garden,  situated  in  a  district  where  peat-loving 
plants  thrive,  might  be  made  beautiful  and  interesting  by 
using  nothing  else  but  these  plants,  and  flowers  could  be  had 
during  the  Avhole  of  the  year,  except,  of  course,  throughout 
prolonged  spells  of  frost.  As  early  as  January  Rhododen¬ 
dron  and  Erica  flowers  are  to  be  found  ;  while  a  succession 
is  kept  up  throughout  spring,  summer,  and  autumn  until 
various  species  of  Arbutus,  Erica,  and  one  or  two 
Rhododendrons  take  up  the  running  in  October,  November, 
or  December,  and  finish  ,  up  the  year  Avith  bright  coloured 
blossoms.  Of  the  large  number  of  subjects  suitable  for 
planting  the  following  is  a  selection  of  the  most  ornamental. 
Although  a  great  many  names  of  Arbutus  are  found  in 
catalogues,  the  number  of  really  hardy  species  is  three,  and 
these,  together  .with  a  number  of  varieties  and  one  or  two 
hybrids,  make  up  a  very  useful  group.  As  a  rule,  they  form 
dense  shapely  bushes,  8ft  to  12ft  high,  but  one  species,  A. 
Andrachne,  from  the  Levant,  grorvs  much  taller,  and 
assumes  the  dimensions  of  a  small  tree.  It  is  a  remarkable 
looking  plant,  especially  about  the  end  of  summer  when 
shedding  its  old  bark.  The  floAvers  are  Avhite,  and  borne 
in  large  panicles.  ;  .  .  -  . 
Of  the  whole  family,  probably  A.  Unedq  is  the  best 
known.  It  is  a  capital  subject  either  for  a  shrubbery  or 
specimen  plant,  as  it  groAvs  into  a  fine  shapely  bush  10ft 
to  12ft  high,  floAvers  freely,  and  bears  shoAvy  orange  and 
scarlet  fruits  on  pendulous  stalks,  from  which  the  common 
name  of  StraAvberry  Tree  is  taken.  A  number  of  varieties 
are  in  cultivation  distinguished  by  differences  in  stature, 
size’,  and  shape  of  leaves,  and  colour  of  floAvers.  The  floAvers 
\-ary  in  colour  from  Avhite  to  deep  rose,  and  a  succession  is 
kept  up  from  October  until  January.  Of  the  several 
varieties,  some,  of  the  most  distinct  are  microphylla, 
quercifolia,  and  rubra.  Another  species  not  so  often  met 
Avith  is  A.  Menzie'si,  from  N.  America.  Of  the  feAv  hybrids, 
that  known  as  hybrid  a,  the  progeny  of  Andrachne  and 
Unedo,  is  the  most  distinct. 
Leaving  this  genus,  ’  and  turning  to  the  large  family 
Erica,  Ave  find  a  great  many  species  Avorthy  attention.  Con¬ 
spicuous  among  them  are  carnea  and  its  variety  alba,  which 
commence  to  floAver.in  February  and  continue  in  good  form 
until  the  end  of  March  ;  mediterranea  and  its  various  forms, 
which  all  flower  in  spring,  particularly  the  plant  knoAvn  as 
hybrida,  an  offspring  of  the  tAvo  above  mentioned  species. 
This  commences  to  floAver  in  January,  and  continues  to 
so  for  quite  three  months,  and  is  without  doubt  one  of 
the  most  useful  of  dwarf  floAvering  shrubs.  A  summer 
floAvering  species  of  considerable  merit  is  cinerea ;  the 
floAvers  of  this  are  rosy  red,  but  there  are  varieties  with 
white,  rose,  deep  red,  and  reddish  purple  floAvers.  For 
autumn  E.  vagans  and  its  varieties  may  be  depended  on  to 
make  a  fine  display  ;  Avhilst  ciliaris,  Macki,  multiflora, 
Tetralix,  and  Watsoni  also  floAAmr  late  in  the  year.  In  warm 
localities  this  list  may  be  lengthened  by  the  inclusion  of 
such  fine  floAvered  species  as  the  red  floAvered  australis,  the 
Avhite  lusitanica,  stricta,  scoparia,  and  others.  With  the 
Heaths  might  be  included  the  Ling,  Calluna  vulgaris,  of 
Avhich  quite  a  score  of  varieties  exist,  varying  in  habit  from 
dAvarf  pigmy  forms  an  inch  or  tAvo  high  to  forms  2ft  in 
height,  and  in  colour  of  flowers  from  white  to  red.  Colour 
of  foliage  also  adds  to  the  varietal  list,  for  there  are  golden 
and  Avhite  variegated  leaved  forms. 
FolloAving  this  large  family  come  a  number-  of  small 
genera,  all  extremely  interesting,  and  the  majority  beautiful. 
Mention  need  only  be  made  of  Andromeda  polifolia,  with 
pretty  pink  flowers  ;  Pieris  japonica,  Avith  large  drooping 
panicles  of  white  blossoms,  or  P.  floribunda,  with  upright 
racemes  of  Avhite  flowers  ;  Zenobia  speciosa,  a  neat  shrub 
Avith  pretty,  Avaxy  white  blossoms,  borne  in  May  and  June  ; 
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