﻿108 
  INTRODUCTION 
  TO 
  BOTANY 
  

  

  and 
  other 
  things. 
  Even 
  in 
  buildings 
  or 
  sailing 
  craft 
  composed 
  

   largely 
  of 
  steel 
  it 
  is 
  therefore 
  found 
  highly 
  desirable 
  to 
  make 
  

   the 
  floors, 
  decks, 
  and 
  much 
  of 
  the 
  interior 
  construction 
  of 
  wood. 
  

  

  6. 
  Wood 
  is 
  a 
  poor 
  conductor 
  of 
  electricity. 
  This 
  makes 
  it 
  

   far 
  easier 
  to 
  manage 
  electric 
  wiring 
  in 
  houses 
  or 
  other 
  build- 
  

   ings 
  in 
  which 
  the 
  floor 
  joists 
  and 
  most 
  of 
  the 
  interior 
  finish 
  

   are 
  of 
  wood 
  than 
  it 
  is 
  in 
  metal 
  structures. 
  

  

  7. 
  When 
  properly 
  finished, 
  wood 
  usually 
  has 
  a 
  highly 
  orna- 
  

   mental 
  surface. 
  This 
  makes 
  it 
  possible 
  to 
  give 
  to 
  the 
  interiors 
  

   of 
  rooms, 
  railway 
  cars, 
  and 
  street 
  cars 
  a 
  decorative 
  effect 
  which 
  

   could 
  be 
  obtained 
  with 
  other 
  materials 
  only 
  with 
  much 
  diffi- 
  

   culty 
  and 
  expense. 
  It 
  is 
  not 
  easy 
  to 
  imagine 
  how 
  beautiful 
  

   furniture 
  of 
  moderate 
  price, 
  such 
  as 
  is 
  made 
  from 
  our 
  orna- 
  

   mental 
  woods, 
  could 
  be 
  made 
  from 
  any 
  metal. 
  

  

  101. 
  Wood 
  as 
  fuel. 
  At 
  present 
  coal 
  is 
  the 
  fuel 
  used 
  in 
  most 
  

   great 
  manufacturing 
  operations, 
  but 
  the 
  world's 
  coal 
  supply 
  

   is 
  limited 
  and 
  seems 
  likely 
  at 
  no 
  very 
  distant 
  day 
  to 
  become 
  

   exhausted. 
  The 
  w 
  1 
  supply, 
  with 
  suitable 
  care, 
  can 
  be 
  con- 
  

   tinually 
  renewed, 
  and 
  wood 
  will 
  probably 
  always 
  remain, 
  as 
  

   it 
  is 
  now, 
  an 
  important 
  portion 
  of 
  the 
  fuel 
  resources 
  of 
  the 
  

   world. 
  The 
  fuel 
  value 
  of 
  wood 
  depends 
  somewhat 
  upon 
  its 
  

   weight 
  per 
  cubic 
  foot, 
  so 
  that 
  such 
  heavy 
  woods 
  as 
  hickory, 
  

   sugar 
  maple, 
  ash, 
  beech, 
  and 
  most 
  oaks 
  are 
  worth 
  more 
  for 
  

   heating 
  purposes 
  than 
  such 
  light 
  woods 
  as 
  willow, 
  cottonwood 
  

   and 
  other 
  poplars, 
  and 
  most 
  pines 
  and 
  other 
  coniferous 
  woods. 
  

   Charcoal 
  is 
  used 
  a 
  good 
  deal 
  as 
  a 
  smokeless 
  fuel 
  and 
  is 
  the 
  

   main 
  combustible 
  ingredient 
  in 
  gunpowder. 
  

  

  102. 
  Coniferous 
  woods. 
  Our 
  native 
  woods 
  1 
  are 
  best 
  clas- 
  

   sified 
  into 
  two 
  principal 
  groups 
  --hard 
  woods 
  and 
  soft 
  woods, 
  

   or 
  coniferous 
  woods.' 
  2 
  The 
  needle-leaved, 
  or 
  coniferous 
  trees 
  

   of 
  the 
  country 
  furnish 
  more 
  than 
  tliree 
  quarters 
  of 
  our 
  timber 
  

   supply. 
  

  

  1 
  "Timber." 
  llnllilhi 
  in. 
  Division 
  <.f 
  Forestry. 
  U.S. 
  Dept. 
  A^r., 
  1805. 
  

  

  - 
  Some 
  of 
  the 
  needle-leaved, 
  or 
  coniferous, 
  trees, 
  such 
  as 
  the 
  larch 
  am' 
  

   the 
  yew, 
  have 
  rather 
  hard 
  wood, 
  and 
  some 
  l>rnad-leaved 
  trees, 
  such 
  as 
  

   willows, 
  poplars, 
  tulip 
  trees, 
  and 
  buckeyes, 
  have 
  soft 
  wood 
  ; 
  but 
  people 
  who 
  

   deal 
  in 
  timlier 
  usually 
  speak 
  of 
  the 
  two 
  general 
  classes 
  as 
  explained 
  above. 
  

  

  