342       SOME  CURIOUS  PROPERTIES  OF  OXIDE  OF  SILVER. 
measured  ijs  rotatory  power  in  the  same  way.  Had  these  pow- 
ers differed  from  each  other  by  the  f0th  part,  I  could  not  have 
failed  to  see  that  they  were  unequal.  No  difference,  however, 
could  be  detected. 
2.  Knowing  the  rotation  produced  by  a  solution  of  narcotina 
to  be  reversed  by  the  addition  of  an  acid,  I  was  anxious  to  as- 
certain whether  the  same  were  true  of  a  solution  of  aconella. 
In  this  experiment  I  was  obliged  to  use  as  the  solvent  rectified 
spirit,  inasmuch  as  the  water  contained  in  the  dilute  acid  which 
I  employed  would  have  rendered  the  chloroform  turbid.  This 
made  the  experiment  more  difficult,  narcotine  being  very  spar- 
ingly soluble  in  spirit.  In  fact,  I  was  with  difficulty  able  to 
dissolve  one  grain  of  either  substance  in  a  cubic  inch  of  cold 
spirit. 
Having  made  two  similar  solutions  of  aconella  and  narcotina, 
I  measured  their  rotatory  powers  before  and  after  the  addition 
of  an  acid.     The  results  were  as  follows  : — 
a.  In  both  cases  the  rotation  was  reversed. 
b.  Working  by  m,  the  ratio  of  the  left-handed  rotation  pro- 
duced by  the  solution  of  aconella  to  the  right-handed  rotation 
produced  by  the  same  solution  when  acidulated,  and  by  m',  the 
same  ratio  for  narcotina,  I  found— 
m 
—  =  1-02. 
m' 
The  acid  used  was  hydrochloric,  and  was  added  in  excess  ; 
the  same  quantity,  of  course,  being  used  for  each  solution. 
These  results  seem  to  leave  little  doubt  of  the  identity  of 
aconella  with  narcotina.  I, am,  &c. 
John  H.  Jellett, 
Professor  of  Natural  Philosophy  to  the  University  of  Dublin. 
Trinity  College,  Dublin,  April,  26. 
Chemical  News,  London,  April  oOth,  1861. 
SOME  CURIOUS  PROPERTIES  OF  OXIDE  OF  SILVER. 
By  M.  Boettger. 
M.  Boettger  has  remarked  that  oxide  of  silver  yields  its 
oxygen  to  combustible  matters  quite  as  readily  as  does  peroxide 
