DESTRUCTION  OF  THE  DRAGON  TREE  OF  TENERIFFE.  271 
this  result  takes  place  even  when  the  nitrate  solution  contains 
copper,  as  is  very  often  the  case.  The  copper,  it  is  true,  becomes 
reduced  by  the  zinc  in  the  ammoniacal  solution,  but  only  very 
slowly  as  compared  with  the  silver,  and  hardly  at  all  so  long  as 
a  certain  quantity  of  the  latter  is  present  in  the  solution.  By 
this  means,  I  have  been  enabled  to  separate  the  whole  of  the 
silver  from  old  coins,  containing  but  twenty-five  per  cent,  of  that 
metal.  Every  particle  of  silver  must  not,  however,  be  separated  ; 
or,  what  is  the  same  thing,  the  quantity  of  zinc  added  should  be 
insufficient  to  precipitate  the  whole  of  it.  The  process  possesses 
the  particular  advantage,  that  in  order  to  separate  copper  from 
nitrate  of  silver,  it  is  not  necessary  to  transform  the  latter  into 
chloride  before  it  can  be  reduced.  The  finely-divided  silver  must, 
however,  be'  treated  in  the  manner  described  above,  with  con- 
centrated hydrochloric  acid,  and  afterwards  well  washed,  to  re- 
move the  particles  of  precipitated  zinc.  For  the  production  of 
pure  nitrate  of  silver,  this  method  is  especially  recommended,  as 
by  its  employment  the  tedious  operations  of  washing  the  chloride 
.of  silver,  and  its  subsequent  reduction  in  crucibles,  are  entirely 
dispensed  with. — London  Chemist  and  Druggist,  March  14,  1868. 
DESTRUCTION  OF  THE  GREAT  DRAGON  TREE  OF  TENE- 
RIFFE. 
The  great  Dragon  Tree  of  Orotava,  Teneriffe,  the  King  and 
Nestor  of  the  Monocotyledons,  is  no  more.  A  drawing  of  it 
made  by  Mr.  Borda,  one  hundred  years  ago,  was  published  about 
60  years  ago  by  Humboldt,  who  first  drew  scientific  attention  to 
this  vegetable  wonder.  The  late  Mr.  Webb  published,  in  his 
history  of  the  Canaries,  figures  of  it  taken  after  the  storm  of 
July  21,  1819  had  destroyed  half  its  crown  ;  and  it  has  recently 
been  described,  measured  and  photographed  by  Prof.  Piazzi 
Smyth.  He  gave  the  trunk  a  girth  of  48 J  feet  at  the  lowest 
accessible  part,  and  a  height  of  60  feet.  Fenzi  of  Florence,  who 
announces  the  demise  of  the  tree,  makes  the  circumference  about 
78  English  feet,  but  intimates  that  he  was  not  able  to  measure 
it  exactly.  When  he.  visited  it,  a  year  ago,  "  it  was  still  in  ex- 
cellent health,  its  immense  crown  covered  with  innumerable  pani- 
cles of  scarlet  fruits,  and  the  huge  trunk,  although  completely 
