8GS 
Supplement  to  the  “ Trnpncal  Apriculturist." 
[Junk  1,  1896. 
what  should  be  the  red  part  of  the  spectrum  ; 
tliree  less  well-defined  ones  blot  out  nearly  all 
the  blue  end,  and  there  are  three  narrower  and 
fainter  ones  in  the  green  and  yellow  regions.  If 
the  leaf  itself  be  examined  with  an  appropriate 
arrangement  of  prisms,  the  same  absor[)tion  of 
light  is  found  to  take  place. 
Here  we  have  the  e.x])lanatiou  for  the  necessity 
of  chlorophyll  and  sunlight.  The  radiant  energy 
of  part  of  the  liglit  is  abaorbod  by  the  chlorojdiyll 
and  affords  the  motive  power  for  the  chemical 
changes  that  take  place,  Many  careful  experi- 
ments led  to  the  conclusion  that  the  most  effec- 
tive rays  are  those  w hicli  correspoiul  to  the 
broad  black  band  in  the  red.  In  other  words 
the  chemical  changes  are  lirought  about  by  the 
energy  derived  from  tlie  sun,  whicli  is  made  to 
do  work  just  as  truly  as  tlio  energy  which  is 
derived  from  the  combustion  of  the  fuel  of  a 
steam-engine. 
But  it  must  not  be  forgotten  that  the  chloro- 
phyll is  associated  witli  protoplasm  in  the  chloro- 
plastid.  The  function  of  the  colouring  matter 
alone  is  only  the  absorption  of  the  liglit;  it  can 
by  itself  go  no  further.  The  absorption  is  the 
same  whether  the  chlorophyll  lie  in  the  {.lastid 
or  in  the  alcoholic  solution;  the  furtlier  effect 
is  different  in  tlie  two  cases.  Tiie  energy  secured 
by  the  chlorophyll  is  rendered  available  by  the 
protoplasmic  element  of  the  corpuscle,  which 
carries  out  the  definite  chemical  change. 
To  trace  the  chemical  reactions  in  detail 
would  be  beyond  the  scope  of  this  paper.  They 
are  very  varied,  and  even  now  very  imperfectly 
understood.  The  result  of  them  is  to  be  found 
in  the  appearance  of  comjjlex  materials  in  the  cell, 
some  of  them  in  solution  in  the  cell-rap,  others 
imbedded  in  the  chloroplastids,  others  included  in 
the  substance  of  the  protoplasm  of  the  cell.  \\  e 
may,  however,  take  a cursory  glance  at  the 
principal  ones,  whose  manufacture  can  lie  LiMCcd 
w'ith  more  cr  less  dilUculty,  particularly  as  they 
readily  fall  into  groujis  such  as  we  shall  see  are 
presenteu  by  the  bodies  linally  .stored  in  the  re- 
servoirs described  above. 
FORESTRY  ITEMS. 
Mr,  A.  C.  Forbes,  writing  on  “ Knots  in  Timlier  ” 
to  the  Timber  Trades  Journal,  says: — 
Timber  without  knots  is  almost  as  rare  as  (ish 
without  bones,  and  yet  for  many  purposes  knots 
must  be  considered  a.s  defects  whicli  dejireciat;  the 
value  of  wood  to  a greater  or  loss  extent.  Where 
wood  is  exposed  to  friction,  as  in  llooring,  or  to 
strains  which  try  its  transverse  strength,  as  in 
rafters,  laths,  joists,  &c.,  knots  are  generally  detri- 
mental to  the  utility  and  clllciency  of  the  goods 
made  from  it,  and  an  endeavour  is  aUvays  made 
to  cut  such  from  tlie  lower  part  of  the  .-.tom  in 
which  the  knots  are  small  and  extend  but  a short 
distance  from  the  centre.  The  most  objectionable 
form  which  knots  assume  i.s  wdien  they  consist  of 
plugs  of  dead  wood  embedded  in  the  green  or 
fresh  timber,  having  no  greater  connection  with 
the  latter  than  a nail  or  staple  driven  into  the 
wood.  Thin  boarding  or  laths  containing  these 
dead  knots  are  of  low  value,  as  the  knots  are  apt 
to  drop  out  when  the  surrounding  wcod  begins 
to  shrink,  leaving  cavities  and  weak  places  in  the 
ivood.  Green  knots  also  weaken  the  tiaiisverse 
strength  of  wood  by  interrupting  the  fibres  and 
weakening  the  elasticity  of  the  wood,  but  as  they 
are  nearly  of  the  same  hardness  and  texture  ao 
the  surrounding  tissues,  and  do  not  interfere  with 
the  cohesive  strength,  they  are  more  readily 
tolerated  than  many  other  defects  commonly 
found  ill  timber. 
]\Ir.  Iludder,  F'^rester,  N.S.W.,  writing  in  the 
A;/ricHltural  Gazette  of  that  Colony,  quotes  the 
follow'ing  authorities  as  to  the  importance  of 
forests  generally  in  the  economy  of  nature  : — 
Mr.  F.  B.  I'lough,  Fh.IJ.,  in  his  Elements  of 
Forestry,  referring  to  the  ruin  that  is  brought  about 
by  the  clearing  of  wood-land.s,  says : — “It  is  a 
familiar  fact  that  there  are  many  legions  in  Asia 
and  Southern  Europe,  once  exceedingly  fertile  and 
densely  ]iopuhited,  that  are  now  utterly  sterile 
and  de.solate.  The  country  bordering  upon  the 
Eiqihra'.cs,  and  portions  of  Turkey,  Greece,  Fgypt, 
Italy  and  Spain  are  noiv  inca])able  of  cultivation 
from  this  cause.”  The  lion.  Geo-  F.  ilarsh,  in  his 
woik  entitled  “The  Earth  as  Modified  by  Human 
Action,"  has  devoted  a large  space  to  the  dhsciis- 
sion  of  the  ([uestion.  A more  recent  illustration 
of  these  elt'ects  is  i)iibli.shed  in  1876  in  the  princi- 
]ial  French  Journal  of  Forestry: — “The  Khoiiote 
ilucharia  presents  a striking  example  of  the 
conseipiences  brought  upon  a country  by  clear- 
ings. Within  a period  of  thirty  years  this 
was  one  of  the  most  fertile  regions  of  Central 
Asia,  a country  which,  wdien  well  wooded  and 
watered,  was  a terrestrial  paradise ; but  w ithin 
the  last  twenty-five  years  a mania  of  clearing  has 
seized  upon  the  inhabitants,  and  all  the  great 
forests  have  been  cut  away,  and  the  little  that 
remained  was  ravaged  by  fire  during  the  civil 
war.  The  consequence  was  not  long  in  following, 
and  has  transformed  this  country  into  a kind  of 
arid  de.sert.  The  watercourses  are  dried  iqi  and 
the  irrigating  canals  empty.  The  moving  sands 
of  the  de.sert,  lieing  no  longer  restrained  by 
barriers  of  forests,  are  every  day  gaining  upon  the 
land,  and  will  finish  by  transforming  it  into  a 
desert  as  desolate  as  the  solitudes  that  seiiarate 
it  from  Khiva.” 
The  Indian  Forester  referring  to  the  Ceylon  Forest 
Administration  Report  for  1894  says  : — We  are  glad 
to  .see  that  attention  is  being  paid  to  the  pal- 
myrah  forests  in  the  north  of  the  l.shiiul,  and  that 
an  officer,  Mr.  Hansard,  has  been  employed  in 
roughly  surveying  the  Crown  lands  in  the  Jaffna 
district  w hich  bear  palmyrah  or  are  fit  for  plant- 
ing with  it.  He  has  reported  that  large  quantities 
of  palmyrah  wood  are  being  exqiorted  to  India, 
and  this  seems  to  point  to  the  importance  of 
enquiries  being  also  made  in  the  neighbouring 
Indian  districts  such  as  Madras,  Tanjore  and 
Tinnevelly,  with  a view  to  making  reserves  there 
also,  in  some  districts  in  Madras,  e.g.,  Nellore, 
palmyrah  areas  have,  we  believe,  been  reserved, 
and  m others,  e.g.,  Cuddapah  and  Anantapur, 
jialmyriih  pbiiitalions  have  been  made,  we  under- 
stand, but  we  have  not  heard  of  any  in  the 
Southern  di.stricts  having  yet  been  formed. 
Nothing  is  more  easy  in  tlie  way  of  plantation 
than  to  grow  palmyrah  ; all  that  is  necessary  is  to 
sow  the  large  fruits  wdiich  germinate  well  and 
then  to  keep  off  cattle.  We  note  that  Mr.  Broun 
gives  80  years  as  the  time  necessary  to  produce 
timber-yielding  ])nlmyrahs. 
