VARIETIES. 
471 
terial  is  employed  in  the  works.  Granitic  and  porphyritic  rocks  abound  in 
the  vicinity,  and  some  parts  of  the  district  produce  iron  and  silver.  Ac- 
cording to  the  Wan-chau  topography,  the  working  of  silver  was  discontin- 
ued in  the  reign  of  Wan-lih,  (1615,)  in  consequence  of  imperial  prohibi- 
tion. This  part  of  the  coast  has  recently  become  the  seat  of  poppy  cultiva- 
tion for  the  bane  of  the  Chinese  race. 
As  a  contribution  to  the  physical  description  of  the  alum  district,  we 
would  add  that  the  typhoon  of  September  last  was  preceded  by  a  rising  of 
water  in  wells  and  ponds  many  miles  inland.  When  the  cyclone  reached 
the  coast,  it  submerged  about  a  hundred  square  miles,  occasioning  a  vast 
destruction  of  life  and  property.  The  waters  of  the  sea  were  retained  in 
the  country  by  strong  easterly  winds  for  several  days,  leaving  a  strip  of 
land  bordering  on  the  sea  quite  dry. — London  Pharm.  Journal,  July  1856. 
Dr.  Boucherie's  Patent  Process  for  Preserving  Wood  from  Decay. — This 
patent  is  for  an  important  improvement  in  the  process  of  preparing  timber, 
so  as  to  preserve  it  from  decay. 
It  is  the  invention  of  the  eminent  French  chemist,  Dr.  Boucherie,  who 
has  devoted  nearly  twenty  years  in  bringing  it  to  perfection. 
The  system  of  Dr.  Boucherie  accomplishes  two  objects: — first,  that  of 
expelling  the  sap  ;  and,  secondly,  filling  the  peres  of  the  timber  with  a  pre» 
servative  solution. 
The  manner  in  which  this  is  effected  is  by  applying  the  preserving  fluid 
under  pressure,  so  as  to  cause  it  to  pass  longitudinally  along  the  fibres, 
The  preserving  fluid  thus  forces  the  sap  out  before  it,  and  occupies  its 
place. 
The  advantages  which  would  result  from  expelling  the  sap,  and  replacing 
it  with  an  antiseptic  fluid,  have  been  long  known,  and  the  idea  of  effecting 
it  by  applying  the  fluid  under  pressure  at  the  end  of  a  piece  of  timber  is 
not  new,  having  been  suggested  and  patented  many  years  ago  by  Mr. 
Bethel,  But  the  means  then  used  did  not  accomplish  the  object  in  such  a 
manner  as  to  admit  of  its  commercial  application. 
Hence  the  more  expensive  process  of  creosoting  has  been  adopted — where 
the  timber  is  totally  immersed  in  the  oil  under  pressure — which  does  not 
permit  the  sap  to  escape. 
Dr.  Boucherie's  process  has  been  attended  with  complete  success.  The 
apparatus  employed,  is  of  a  very  inexpensive  character,  and  may  be  erected 
in  a  few  days ;  it  is  capable  of  application  on  the  most  extended  scale  ;  and 
it  is,  in  fact,  very  extensively  employed  at  this  time  in  preparing  sleepers 
and  telegraph  posts  for  the  French  railways. 
When  the  timber  is  under  operation,  the  sap  runs  out  from  the  ends  in 
a  clear  stream,  showing  the  amazing  quantity  of  this  fluid  which  is  con- 
tained, and  exhibiting  the  tubular  structure  of  the  wood,  in  the  most  strik- 
ing manner  ;  in  fact,  the  preserving  fluid  will  traverse  a  tree  twelve  feet  in 
