236        NEW  APPLICATION  OF  COLLODION  IN  THE  ARTS. 
warm  liquid,  completely  thrown  down  again  by  cooling  ;  at 
_L.th  slight  turbidity,  which  becomes  more  sensible  by  long  boil- 
ing. 
Bigitaline. — At  ^th  slight  turbidity,  which  at  first  disap- 
pears by  boiling,  and  then  gives  place  to  a  voluminous  precipi- 
tate. 
Aconitine — At  ^th  copious  white  precipitate  ;  at  -^th  tur- 
bidity ;  at  — L^th  liquid  becomes  opalescent. 
Caffeine. — At  JLth  no  reaction. 
M  1000 
Theobromine. — At  JLth  slight  muddiness. — Ohem.  News,  Lon- 
1000        °  ' 
don,  Jan.  21,  1860,  from  Journ.  de  Pharmacologie  de  Bruxelles, 
Dec.  1859. 
NEW  APPLICATION  OF  COLLODION  IN  THE  ARTS,  BY  PATENT. 
Collodion  and  castor  oil  have  received  a  new  application. 
Messrs.  Barnwell  and  Rollason  use  the  mixture  for  making  silks 
and  other  woven  fabrics  waterproof.  Their  manner  of  proceeding 
is  as  follows  : — "Assuming  the  material  under  operation  to  be  silk, 
we  take  collodion  and  mix  it  with  vegetable  oil,  such  as  either 
hempseed,  rape,  olive,  almond,  nut,  poppy,  castor,  cotton,  or 
linseed  oil,  in  the  purest  possible  state,  and  we  find  that  such 
oils  when  mixed  with  collodion  undergo  a  change  upon  being- 
subjected  to  heat,  and  this  change  or  decomposition  is  highly 
advantageous  in  the  subsequent  processes  to  which  the  silk  will 
be  applied.  The  mixture  of  collodion  and  oil  is  spread  or  poured 
upon  plates  or  cylinders  of  metal  or  glass,  and  before  it  is  quite 
set  the  silk  is  laid  or  rolled  over  it  and  immediately  removed, 
bringing  away  with  it  a  thin  film  of  collodion  and  oil.  The  silk 
thus  coated  is  now  removed  to  a  stove  or  drying  oven  and  sub- 
mitted to  a  heat  of  100°  to  300°  Fahrenheit,  by  which  the  mix- 
ture undergoes  the  before  named  change  or  decomposition,  and 
the  result  is  that  a  slightly  glazed  appearance  is  imparted  to  the 
silk,  which  is  at  the  same  time  considerably  strengthened  or 
thickened,  and  may  be  rendered  almost  or  quite  opaque  by  the 
mixture  of  coloring  or  thickening  matter  with  the  collodion  and 
oil.    A  thin  silk  is  thus  rendered  equal  in  strength  to  a  more 
