SoreVs  ISubstitutes  for  Gutta-percha
ami  OtotUchouc.  I.  Mix  colopnony  2
parts,  pitch  or  asphaltum  2,  rosin  oil  8,
calcium  hydrate  6,  water  3,  alumina  10,
and  gutta-percha  12.  Heat  the  colo-
phony, j)itcli,  and  ro3in  oil  in  a  boiler
and  stir  until  the  resin  and  pitch  are
dissolved.  Then  stir  the  calcium  hy-
drate into  a  thin  paste  with  water,  add
it  to  the  above  mixture  and  beat  the
mass  ag:ain,  stirring  constantly.  When
all  are  intimatjiy  mixed  add  the  gutta-
percha cut  in  small  pieces.  Then  con-
tinue heating  and  stirring  until  the
gutta-percha  is  licjuefied,  and  then  add
the  alumina  previously  pulverized  and
mixed  with  water.  As  soon  as  this  is
equallv  distributed  in  the  mixture,  re-
move ihe  excess  of  water  and  bring  the
whole  to  the  boiling  point.  If  any  more
water  separates  remove  it,  then  knead
the  composition  with  fresh  water,  and
finally  pass    it  through  rollers.      To


make  the  com{>o8ition  entirely  water-
proof, add  5  per  cent,  of  stearic  acid.
II.  Pitch  8  parts,  rosin  oil  4,  cal-
cium hydrate  6.  and  gutta-percha  16,

III.  Pitch  Iz  parts,  calcium  hy-
drate 6,  gutta-percha  16.
IV.  Coal-tar  12  parts,  calcium  hy-
drate 6,  gutta-percha  16.
The  above  compositions  are  used
for  manufacturing  water-proof  articles,
tubes,  machine  belts,  water-proof  boots
and  shoes,  etc.  If  greater  tenacity  is  to
be  imparted  to  the  compositions  add
fibrous  substances,  as  cotton,  wool,
hemp,  etc.
