558  PRODUCTION  OF  ALIZARIN  FROM  NAPTHALIN. 
The  author  afterwards  occupied  himself  with  preparing  an- 
hydrous permanganic  acid.  He  finds  that  this  preparation  can 
be  made  without  danger,  even  when  operating  with  20  grammes 
of  permanganate,  by  taking  care  to  cool  the  sulphuric  acid 
(1-845  density)  with  a  refrigerating  mixture,  and  by  gradually 
introducing  the  permanganate,  which  must  be  free  from  all 
chloretted  combinations. 
The  dissolved  permanganic  acid  colors  the  acid  dark  green, 
forming  at  the  same  time  some  oily  drops,  which  fall  to  the 
bottom  of  the  vessel,  and  which,  after  a  time,  or  rather  when 
the  mixture  is  heated,  disengage  oxygen.  Manganate  of  potash 
behaves  in  an  analogous  way.  There  is  always  a  deposit  of 
peroxide  of  manganese,  the  manganic  acid  immediately  decom- 
posing into  peroxide  and  permanganic  acid. 
Permanganic  acid  forms  a  dark  brown-red  liquid,  fluid  at 
20^,  very  unstable,  attracting  humidity  and  decomposing  with 
disengagement  of  oxygen.  It  gives  no  trace  of  vapor  in  an 
exhausted  receiver,  and  when  heated  to  above  65^  it  detonates 
violently  with  flame,  and  is  transformed  into  sesquioxide  of 
manganese.    Its  composition  answers  exactly  to  the  formula 
When  permanganates  or  manganates  contain  chlorides  the 
phenomena  are  different,  and  the  yellow  vapors  obtained  by 
M.  Dumas  are  produced  by  adding  sea  salt  to  a  mixture  of  per- 
manganate of  potash  and  sulphuric  acid. 
M,  Aschoff  has  not  succeeded  in  condensing  a  sufficient 
quantity  of  these  vapors  for  analysis ;  but  he  has  collected  and 
studied  some  small  drops  analogous  to  anhydrous  permanganic 
acid,  which  are  also  isolated  in  this  experiment,  and  the  com- 
position of  which  answers  to  the  formula  of  Mn2C10g.  This 
body  may  be  a  new  combination  or  a  mixture  of  anhydrous  per- 
manganic acid  and  a  chloretted  combination  of  manganese./ — 
London  Ohem.  JSfews,  Aug.  24,  1861. 
THE  PRODUCTION  OF  ALIZARIN  FROM  NAPHTHALIN. 
M.  Z.  Roussin  has  communicated  to  the  French  Academy  a 
process  for  the  conversion  of  naphthalin  into  alizarin.  This  re- 
sult, if  really  practicable,  will  prove  of  considerable  importance. 
