258       SODIUM  FOR  PHOSPHORUS  IN  LUCIFER  MATCHES. 
with  explosive  substances,  becomes  highly  inflammable  when 
simply  moistened  with  water.  A  mixture,  constituted  according 
to  the  formula — 
(KO,NO,)+Na+2C=(KO,C02+NaO,G02HN, 
formed  a  greyish-colored  mass,  which,  on  being  touched  with  a  ^ 
moistened  glass  rod,  ignited  like  gunpowder  ;  this  mixture  was, 
however,  found  to  be  unfit  to  ignite  ordinary  brimstone  matches 
for  a  cotton  wick  soaked  in  petroleum.  In  order  to  mend  this 
defect,  black  sulphuret  of  antimony  was  substituted  for  the  char- 
coal, according  to  the  formula — 
3(KO,NO,)+Na-f-(SbS3)-=NaO,Sb05)+3(KO,S03)-l-3N, 
and  the  mixture  made  up  of — 
0*5  grammes, of  sodium  =   4-65  per  cent. 
66-0  nitrate  of  potash  ,    .    .  =  61-39  " 
36-5       "  sulphide  of  antimony     .  =  33-96  " 
Provided  that  during  its  manufacture  this  mixture  is  kept 
thoroughly  dry,  it  has  been  found  to  answer  admirably  well. 
The  mode  of  making  it  up  is  briefly  as  follows  — Pure  solid  paraf- 
fin is  put  into  a  well-stoppered  glass  flask,  and  melted  over  a 
sand  bath ;  when  fluid,  clean  pieces  of  sodium  are  added,  and 
liquefied  under  the  paraffin.  As  soon  as  the  metal  is  thoroughly 
liquefied,  the  flask  is  closed  and  shaken  for  about  ten  minutes, 
which  has  the  eff'ect  of  granulating  the  metal,  or  rather  reducing 
it  to  a  fine  powder.  The  metal  is  then  poured  out  of  the  flask 
along  with  the  paraffin,  and  the  sodium  taken  out  of  the  paraffin 
by  means  of  a  clean  dry  spoon ;  from  30  to  35  per  cent,  of 
paraffin  remains  adhering  to  the  metal ;  this,  however,  does  not 
impair  its  inflammability,  while  it  tends  to  preserve  the  metal. 
Owing  to  this  increase,  instead' of  5  grammes,  6-6  grammes  of 
the  metallic  powder  thus  obtained  must  be  weighed  off".  The  in- 
corporation with  the  other  ingredients,  previously  well  dried  and 
warm,  is  eff'ected  under  petroleum  in  metallic  mortars,  but  each 
of  the  substances  is  first  mixed  with  some  petroleum,  and  pul- 
verized separately  before  being  triturated  with  the  sodium ; 
instead  of  gum  or  glue,  caoutchouc,  previously  soaked  in  light 
petroleum  oil  at  110°  C.  for  ten  or  twelve  hours,  is  used  as  mass 
to  form  an  adhesive  paste  with  the  other  materials.  According 
