MANUFACTURE  OF  PERCHLORIC  ACID. 
21 
perchloric  acid,  requiring  65  times  its  weight  of  water,  at  60°  F., 
for  solution. 
To  obtain  perchloric  acid  from  perchlorate  of  potash,  the  salt 
is  distilled  (below  the  boiling  heat  of  the  ingredients)  with  twice 
its  weight  of  sulphuric  acid  mixed  with  one-tenth  part  of  water, 
as  long  as  any  distillate  is  obtained.  The  distillate,  containing 
perchloric  and  sulphuric  acids,  together  with  some  free  chlorine, 
and  a  little  hydrochloric  acid,  is  treated  with  carbonate  of  lead 
rubbed  into  a  paste  with  wTater,  till  baryta  water  no  longer  dis- 
turbs the  clear  solution.  Should  an  excess  of  carbonate  of  lead 
have  been  used,  the  perchlorate  of  lead  is  to  be  carefully  de- 
composed by  sulphuric  acid.  The  weak  acid  is  now  filtered  from 
the  sulphate  and  chloride  of  lead,  and  a  few  drops  of  hydrosul- 
phuric  acid  added,  to  decompose  the  slightly  soluble  chloride  of 
lead.  After  boiling,  the  acid  is  again  filtered,  and  may  now  be 
concentrated  in  an  open  capsule  below  boiling  until  it  attains  a 
specific  gravity  of  1*6,  or  thereabouts,  when  it  commences  to 
give  off  white  vapors.  By  distillation  of  this  product  an  acid 
having  the  density  of  1-693  is  obtained. 
One  pound  of  perchlorate  of  potash  yielded  five  ounces  of 
acid  of  a  density  of  1-210. 
The  properties  of  perchloric  acid  have  been  so  fully  described 
by  Prof.  Roscoe,  (vol.  xxxiv.  p.  64  of  this  Journal),  that  further 
notice  is  unnecessary. 
The  effect  of  this  acid,  sp.  gr.  1-693,  was  tried  on  the  follow- 
ing articles  with  morphia,  codeia,  narcotina,  and  atropia  ;  no 
reaction.  With 
Meconin,    flesh  color. 
Quinia,       pale  straw  color. 
Strychnia,  pale  yellow. 
Brucia,       rose  color. 
Delphia,     a  dirty  red  color. 
Aconitia,    a  light  ochry  yellow. 
Digitalin,    snuff  brown. 
Perchlorate  of  Morphia. 
Dr.  Ogden,  in  his  analysis  of  chlorodyne,  claims  perchlorate 
of  morphia  as  one  of  its  ingredients.    The  following  short  no- 
