^'/an^ifs?1"111'}  Ammonio-nitrate  of  Silver.  25 
cc.  To  the  other  nine  tubes  the  ammonia  solution  was  added  in  de- 
creasing proportion,  thus  : — 
Number  of 
tube. 
Cubic  centimeters 
IN  n  4  yj  li  ilUUcU.. 
Weight  of  precipitate 
in  grammes. 
10 
1-30 
9 
117 
0-008- 
8 
1-04 
7 
0-91 
0-054 
6 
078 
5 
0-65 
0-076 
4 
0-52 
3 
0-39 
0-069 
2 
0-26 
1 
0-13 
0-044 
In  none  of  the  nitrates  did  either  ammonia  or  silver  nitrate  give  a 
precipitate.  As  nearly  as  could  be  noted  by  observation  the  amount 
of  precipitate  increases  from  Xo.  1  to  Xo.  3  and  in  Ko.  5  seems  to 
attain  its  maximum. 
It  then  diminished,  until  in  tube  No.  9  there  was  but  little  appar- 
ent precipitate. 
To  obtain  more  precise  results  weighings  were  made  of  the  precipi- 
tates in  alternate  tubes-  and  the  result  of  these  are  given  in  the  third 
column  of  the  table. 
As  it  was  obviously  important  that  this  precipitate  should  be  exam- 
ined, and  as  the  maximum  quantity  obtainable  was  only  equal  to  4*47 
per  cent,  of  the  silver  nitrate  employed,  its  preparation  on  a  larger 
scale  became  necessary.  One  hundred  and  seventy  grammes  silver 
nitrate  were  dissolved  in  170  cc.  distilled  water  and  64*5  cc.  of  the 
ammonia  solution  added ;  just  half  the  quantity  required  for  re-solu- 
tion of  the  precipitate.  The  liquid  became  very  hot,  but  the  nitrate 
afforded  no  further  precipitate  either  on  cooling  or  on  dilution  with 
water.  A  determination  in  it  of  the  silver  as  chloride  showed  that 
only  11  per  cent,  of  the  nitrate  had  been  precipitated,  and  therefore 
that  the  remaining  89  per  cent,  had  been  dissolved  in  the  ammonium 
nitrate  formed. 
The  precipitate  was  collected  and  examined  after  being  simply  air- 
dried  under  a  bell  glass. 
