CHEMICAL  ACCURACY. 
133 
mixture ;  if,  however,  poppy-seed  oil  is  mixed  with  either  of  the 
two  oils  just  mentioned,  and  the  same  experiment  then  repeated, 
the  mixture  gets  the  appearance  of  a  liniment  from  which  no  oil 
separates.  Sweet  oil  of  almonds,  adulterated  with  one-eighth  part 
of  poppj-seed  oil,  behaves  as  if  it  were  almost  pure  poppy-seed 
oil.  Biichner  and  Brande  have  found  Lipowitz's  statements 
correct  as  regards  sweet  oil  of  almonds,  but  not  as  regards  oil  of 
olives  ;  but  they  add  that  the  olive  oil  they  operated  upon  was 
already  old.  The  action  of  Lipowitz's  reagent  is  explained  by 
the  fact  of  the  rapid  oxidation  of  all  so-called  drying  oils  which, 
on  drying,  yield  solid  products  before  entirely  changing,  by  con- 
tinuously absorbing  oxygen  into  water  and  carbonic  acid.  Lin- 
seed oil,  hemp-seed  oil,  poppy-seed  oil,  oil  from  walnuts,  croton 
oil,  castor  oil,  are  all  drying  oils.  The  drying  of  drying  oils  is, 
in  fact,  a  process  of  slow  oxidation  of  these  oih.—Ohein.  News, 
Jan.  1,  1869, /rom  N.  Br.  Arch, 
CHEMICAL  ACCURACY. 
By  Wm.  Crookes,  F.R.S. 
We  cannot  see  the  tendency  towards  exactness  and  clearness 
better  than  by  taking  a  chemist's  view.  Air  was  once  the  soul 
of  the  world,  it  was  the  life  of  man,  it  was  a  spirit  including  in- 
tellect, it  was  a  ghost,  it  was  capable  of  turning  into  water, 
which  again  became  earth,  and  it  was  in  itself  nothing  material, 
and  had  no  weight  or  substance.  Now  it  has  fallen  into  the 
ranks  of  ordinary  things,  although  not  less  wonderful.  It  has 
been  divided  into  parts,  although  unseen.  This  very  spirit  of 
the  world  has  been  dissected,  and  chemists  treat  it  without  rever- 
ence, measuring  it  out  in  tubes  or  weighing  it  on  balances. 
Now  we  can  scarcely  tell  how  various  its  composition.  It  has 
two  principal  parts,  but  a  third  was  soon  added,  whilst  a  fourth, 
under  the  name  of  ozone,  has  been  followed  by  the  scent  for 
many  years — we  may  even  say  since  those  ancient  days  when 
the  smell  was  observed  after  violent  lightning.  Now  we  have 
plants  and  animal  diseases  almost  endless,  and  strange  influences 
accompanying  every  wind.  These,  by  degrees,  the  scientific 
inquirer  is  hunting  down,  and  preparing  for  the  world  new  mu- 
