424 
THE  MAGNESIAN  LIGHT. 
furnishes  an  easy  means  of  estimating  a  mixture  of  cane  sugar 
and  dextrine.  Boiling  for  a  minute  with  the  acid  is  sufficient  to 
modify  all  the  cane  sugar,  so  as  to  render  it  fit  for  the  cupro- 
potassic  tartrate  test,  while  the  dextrine  undergoes  no  change  in 
the  same  time.  If  any  starch  were  present  at  the  same  time  it 
might  be  got  rid  of  by  diastase,  which  has  no  action  either  on 
the  cane  sugar  or  dextrine.  3.  The  action  of  diastase  explains 
how  it  is  that  brewers  are  obliged  to  employ  an  enormous  quan- 
tity of  barley  to  obtain  a  beer  with  but  little  alcohol  :  'two  thirds 
of  the  starch  pass  into  dextrine.  4.  That  in  making  spirit 
from  malt  there  is  an  inevitable  loss  of  two  thirds. —  Qhem.  News, 
London,  May  19,  1860. 
PREPARATION  OF  NICOTINA. 
M.  Debize  (Moniteur  Scientifique,  p.  691,)  prepares  nicotina 
by  placing  a  mixture  of  lime  and  powdered  tobacco  in  a  cylinder 
and  passing  through  it  a  current  of  heated  steam.  The  oppo- 
site end  of  the  cylinder  to  that  at  which  the  steam  enters  is  con- 
nected with  a  worm  which  condenses  the  steam  and  the  products 
carried  along  with  it,  nicotina,  ammonia,  and  some  undefined 
bases.  In  order  to  separate  the  nicotina  the  liquid  is  neutral- 
ized with  sulphuric  acid  and  then  concentrated  by  evaporation. 
When  sufficiently  concentrated  it  is  treated  with  ammonia  and 
ether,  by  which  means  an  ethereal  solution  of  nicotina  is  obtained 
which  can  be  easily  separated  and  the  nicotina  purified  by  recti- 
fication.—  Chem.  News,  London,  May  26,  1860. 
THE  MAGNESIAN  LIGHT. 
Magnesium  is  well  known  as  the  metallic  bases  of  magnesia  ; 
it  is  much  lighter  than  aluminium,  as  its  specific  gravity  is  only 
1-74 ;  it  is  of  a  silvery  whiteness,  undergoes  no  change  in  dry 
air,  and  is  subject  to  but  slow  oxidation  in  a  damp  atmosphere, 
and  that  only  quite  superficially;  it  may  be  hammered,  filed, 
and  drawn  into  threads.  At  the  beginning  of  the  present  cen- 
tury its  properties  were  developed  by  Davy,  and  still  more 
thoroughly  by  Bussy.  To  obtain  it  pure  is  an  expensive  pro- 
cess ;  and  as  no  practical  advantage  could  hitherto  be  made  of 
