542  Preservation  of  Hydrogen  Peroxide.  {X^X^^ 
the  amount  required  having  been  previously  determined  by  titration. 
At  the  end  of  six  months  the  solutions  to  which  acetanilide  had  not 
been  added  were  found  to  be  so  far  decomposed  that  the  experiments 
were  not  continued.  One  c.c.  of  the  solutions  of  Series  IV  required 
at  the  beginning,  21.40  c.c.  x/10  thiosulphate. 
Age  at  time  of  test. 
2  months  6  months 
Original  solution  12 .  i    3 . 75 
Original  solution  with  acetanilide  21 . 05  19 
Nad  —  I2-5   3 
5000 
NaCl  h  acetanilide  21.0  19 
5000 
KC1  —  I2-75  •  4 
5000 
KC1          +  acetanilide  20 . 95  19 
5000 
CaCl2—  •  13.05...  4 
5000 
CaCl2  ■  +  acetanilide  ,  20.95  l9 
5000 
Na2Si03—     10. 6  2 
3000 
Na2Si03  ■  +  acetanilide  20 . 75  19 
3000 
FeClj  1  h  acetanilide  20 . 40  18 
500,000 
A12(S04)3  P  acetanilide  21 .05 ....  19 
500,000 
Series  V:  Solutions  ^|  Normal  in  H2S04.  Effect  of  Various 
Salts  aloxe  and  with  Acetaxilide. 
The  calcium  sulphate  was  added  in  pure  crystals.  In  all  other 
cases  the  same  procedure  was  followed  as  in  making  the  solutions  of 
Series  IV.  Just  after  being  prepared,  1  c.c.  of  the  solutions  required 
22.95  c.c.  n/io  thiosulphate. 
Age  at  time  of  test 
2  months  6  months 
Original  solution  14 . 35   5 . 35 
Original  solution,  acetanilide  22 . 65  22 . 30 
Na2S04  —  •  I5  30   6.30 
5000 
Na2S04        +  acetanilide  22.75  22  •  35 
K2S04—  15.60....   6.65 
5000 
