RELATIONS  OF  THE  SOIL  TO  VEGETATION.  469 
As  the  mass  contains  no  phosphorus,  their  manufacture  pre- 
sents no  danger  for  the  workpeople,  as  thej  neither  cause  explo- 
sions, nor  injurious  emanations.    The  mass  of  these  matches, . 
which  were  patented  in  France  in  March  1857,  contains  the  fol- 
lowing substances : — 
Dextrine  .10  parts. 
Chlorate  of  potash         ...  17  " 
Brown  oxide  of  lead       %       .       .  35  " 
Iron  pyrites  ....  35  " 
Water,  the  quantity  necessary  to  form  a 
uniform  paste. 
The  chlorate  of  potash,  the  oxide  of  lead,  and  iron  pyrites 
are  separately  powdered,  and  then  made  into  a  paste  by  means 
of  the  solution  of  dextrine  ;  into  this  the  ends  of  the  sulphured 
matches  are  dipped  in  the  usual  way. 
The  dextrine  might  be  replaced  by  gum  or  glue,  and  the  iron 
pyrites  by  other  metallic  sulphurets,  to  some  of  which,  however, 
it  is  preferable  as  not  being  poisonous. 
2.  Safety -matches  with  a  peculiarly  prepared  Friction-surface. 
A  second  patent  of  Canouil's,  dated  October  7,  1857,  relates 
to  safety-matches  of  wood,  wax  paper,  German  tinder,  &c, 
which  ignite  only  at  a  particular  surface,  containing  no  phos- 
phorus. The  latter  consists  of  a  slip  of  wood,  card,  or  metal, 
covered  with  a  layer  of  the  preparation,  which  causes  the  ignition 
of  the  chemical  matches  by  mere  friction.  Such  matches  may 
be  sent  anywhere  without  the  least  danger,  as  the  matches  and 
the  friction-surfaces  may  be  packed  in  separate  boxes.  The 
mass  for  the  matches  consists  of — 
Chlorate  of  potash  ...  .5  parts. 
Acetate  of  lead  .       .       .        .    2  " 
Bichromate  of  potash  .  .  .  '  .  2  " 
Flowers  of  sulphur      .       .       .  1  " 
Gum  or  dextrine         .       .       .        .    6  " 
Water  18  « 
The  covering  for  the  friction-surface  consists  of — 
Iron  scales         .....  lpart. 
Emery       .        .        ...  1  " 
Chlorate  of  potash        .       .       .  6  " 
Minium      .  ...  1  " 
