176 
VARIETIES. 
degree  of  temperature,  and  then  suddenly  plunging  it  into  the  solutions, 
have  been  condemned  by  the  highest  authorities. 
In  the  Ordnance  Manual  for  the  use  of  the  officers  of  the  United  States 
Army,  edited  by  Major  Mordecai,  assisted  by  Colonels  Baker,  Ripley,  II  u- 
ger,  and  Major  Symington,  able  officers,  honored  alike  for  attainments  in 
science  and  services  rendered  under  the  flag  of  their  country,  it  is  stated 
that  "  kiln  drying  is  serviceable  only  for  boards  and  pieces  of  small  dimen- 
sions, and  is  apt  to  cause  cracks  and  to  impair  the  strength  of  wood,  unless 
performed  very  slowly,  and  that  charring  or  painting  is  highly  injurious 
to  any  but  seasoned  timber,  as  it  effectually  prevents  the  drying  of  the  in- 
ner part  of  the  wood,  in  which  consequently  fermentation  and  decay  soon 
take  place.  Also  in  noticing  Earle's  process,  which  consists  in  saturat- 
ing the  wood  in  a  hot  solution  of  copperas  and  blue  vitriol  mixed  togeth- 
er, has  been  tried  by  the  ordnance  department,  but  the  results  have  not 
been  favorable  as  far  as  regards  its  effects  upon  the  strength  and  preser- 
vation of  the  timber."  Boucherie  also  mentions  his  want  of  success  in 
rarefying  by  a  regulated  heat,  the  air  included  in  the  interior  of  the  wood, 
and  then  plunging  it  at  once  into  the  solutions,  which  he  wished  to  intro- 
duce, though  by  this  method,  he  caused  different  liquids  to  penetrate  ma- 
terials of  a  very  compact  nature  ;  and  he  succeeded  forcing  tar  into 
stones  and  bricks  to  a  very  great  depth.  The  same  authority  states,  "  That 
it  is  infinitely  more  advantageous  to  act  upon  wood  in  its  green  state,  than 
to  prepare  it  after  the  time  necessary  for  its  complete  dessication  had  sen- 
sibly altered  it." 
Tredgold,  in  his  able  and  lucid  manner,  accounts  for  the  effects  upon 
the  durability  of  timber  produced  by  these  processes  which  have  thus  been 
condemned — he  says,  "  that  it  is  well  known  to  chemists  that  slow  drying 
will  render  many  bodies  less  easy  to  dissolve,  while  rapid  drying,  on  the 
contrary,  renders  the  same  bodies  more  soluble  ;  besides,  all  wood  in  dry- 
ing loses  a  portion  of  its  carbon,  and  the  more  in  proportion  as  the  tem- 
perature is  higher;  there  is  in  wood  that  has  been  properly  seasoned  a 
toughness  and  elasticity  which  is  not  to  be  found  in  rapidly  dried  wood, 
and  this  is  an  evident  proof  that  firm  cohesion  does  not  take  place  when 
the  moisture  is  dissipated  at  a  high  heat. 
The  evidence  of  the  Saxon  and  Bohemian  railways  given  in  the  29th 
number  of  the  Eisenbahnzeitung ,  and  translated  to  the  valuable  columns  of 
the  United  States  Mining  Journal,  practically  confirms  the  unfavorable 
views  of  the  authorities  here  quoted. 
Additional  adverse  testimony  could  still  be  brought,  but  its  introduction 
here  would  extend  this  communication  to  a  wearisome  prolixity. 
The  employment  of  the  popular  European  methods  of  Bethell  and  Sir 
William  Burnett  upon  American  railways,  which  are  too  often  started  in 
haste,  and  without  the  means  sufficient  to  properly  complete  them, — would 
be  attended  with  two  objections,  in  some  instances  so  weighty  as  to  pre- 
vent their  adoption, — they  are, 
