86 
VARIETIES. 
niinate  of  potash  or  soda,  instead  of  free  alkali.  An  equally 
good  result  is,  however,  obtained  by  mixing  free  alumina,  in  dry 
powder,  with  melted  soap  which  has  been  manufactured  in  the 
ordinary  way.  M.  Bonnamy  proposes  to  use  alumina,  also,  in 
various  cosmetics,  and  especially  in  cold  cream,  and  he  more- 
over regards  it  as  affording  an  admirable  base  for  tooth-powders, 
by  reason  of  its  complete  neutrality,  and  the  ease  with  which  it 
can  be  tinted  by  means  of  perfectly  innocent  coloring  matters. — 
Scientific  American. 
ANILINE    AS    A    TEST    FOR   THE  ADULTERATION  OF 
LINEN  BY  COTTON. 
A  method  of  using  aniline  as  a  means  of  ascertaining  whether 
or  not  the  linen  in  any  fabric  is  mixed  with  cotton,  and,  if  so, 
in  what  proportion,  is  given  by  Bottger  in  a  recent  number  of 
the  u  Chemisches  Central  Blatt."  At  the  corners  of  one  end 
of  a  strip  of  the  fabric  to  be  tested  he  loosens  the  threads  so  as 
to  expose  both  the  warp  and  the  woof.  He  then  clips  that  end 
of  the  strip  in  an  alcoholic  solution  of  aniline  red,  washes  it  in 
water  until  the  washings  are  colorless,  and  then  places  it  in  an 
aqueous  solution  of  ammonia.  If  any  cotton  is  present,  the 
ammonia  will  discharge  the  color  from  it  without  touching  the 
color  of  the  linen  portion.  The  linen  threads  will  remain  of  a 
bright  rose  color,  but  the  cotton  threads  will  become  quite 
white. — Scientific  A merican . 
On  the  Oxidation,  of  Fatty  Vegetable  Oils. — In  a  memoir  presented  bv 
M.  Cloez  to  the  French  Academy  of  Sciences,  he  treats  of  the  influence  of 
light  and  heat  on  oxidation.  The  author's  results  are  of  much  interest. 
He  exposed  oils  to  the  air  in  colorless  glass  vessels,  and  also  in  vessels  of 
red,  yellow,  green,  and  blue  glass,  and  also  left  some  oil  exposed  to  air  in 
total  darkness.  After  ten  days  exposure,  the  increase  of  weight  was 
greatest  in  the  colorless  glass  vessel  ;  it  was  rather  less  in  the  blue  glass  ; 
was  very  small  in  the  red,  yellow,  and  green  ;  and  no  increase  of  weight 
at  all  was  observed  in  the  oil  exposed  in  the  dark.  Like  results  were 
found  after  twenty  days  ;  but  after  thirty  days  exposure,  the  results  were 
