346 
PREPARATION  AND  PROPERTIES  OF  MAGNESIUM. 
the  filtered  liquid  and  distilling  it  in  a  not  too  concentrated  state 
with  peroxide  of  manganese  and  moderately  strong  sulphuric 
acid ;  the  least  proportion  of  kinic  acid  in  the  liquid  is  soon  indi- 
cated by  the  development  and  evolution  of  kinone,  which  takes 
place  during  this  process ;  and  the  smallest  quantity  of  the  ki- 
none, which  is  not  distinctly  perceptible  by  the  smell,  may  be 
soon  detected  by  the  dark  color,  which  the  distillate  assumes 
upon  the  addition  of  a  few  drops  of  a  solution  of  ammonia. 
This  method  of  testing  barks  is  distinguished  from  others  by 
its  great  simplicity,  by  the  correctness  of  the  results,  and  by  the 
possibility  of  detecting  and  quantitatively  determining  in  one 
succession,  and  with  the  same  material,  all  the  more  important 
constituents  of  the  bark  ;  I  consider  it  as  the  best  method  known, 
not  because  it  originates  with  me,  but  because  it  is  adapted  for 
the  present  stage  of  our  knowledge  of  the  chemical  composition 
of  cinchona  barks,  and  is  practical.  It  may  be  objected  that  it 
is  rather  troublesome,  but  this  ought  not  to  be  of  any  considera- 
tion if  we  can  be  but  sure  of  a  correct  result. 
In  conclusion,  I  must  observe,  that  my  method,  though  chiefly 
adapted  for  testing  genuine  barks,  can  be  advantageously  applied 
for  examining  new  and  apparently  spurious  barks.  The  occur- 
ring  phenomena  will  then  safely  guide  the  experienced  operator. 
With  the  barks  containing  paricine,  the  separation  of  the  alka- 
loid is  made  very  difficult,  by  its  forming  with  the  cinchona  red 
contained  in  the  bark,  compounds  soluble  in  acids  and  alkalies, 
which  can  be  decomposed  only  with  great  difficulty.  I  refer  in 
this  respect  to  my  last  treatise  on  the  Production  and  the  Che- 
mical Condition  of  Paricine,  in  Buchner's  Repertorium. — Lon- 
don Pharm.  Journ.,  March,  1853,  from  Jalirbuch  /,  Pharm. 
ON"  THE  PREPARATION"  AND  PROPERTIES  OF  MAGNESIUM. 
By  R.  Bunsen. 
According  to  Bunsen,  fused  chloride  of  magnesium  is  readily 
decomposed  by  the  galvanic  current.  A  metallic  mass  of  several 
grammes  in  weight  may  be  prepared  in  a  short  time  with  a  few 
pairs  of  the  carbo-zinc  battery. 
Magnesium  obtained  in  this  manner,  when  freshly  broken,  is 
sometimes  slightly  crystalline  and  laminar,  sometimes  finely 
i 
