244 
ON  THE  CONSTITUTION  OF  QUININE. 
II.  2'0910  grm.  air-dry  salt,  of  another  crystallization,  lost,  at 
120°  C.,  0.0965  grm.  water. 
III.  11415  grm.  dried  at  120°  C,  formed  0*3575  grm.  sulphate 
of  baryta. 
IV.  0.7915  grm.  dried  at  120°  C,  gave  0*2500  grm.  sulphate 
of  baryta. 
The  formula  of  the  air-dry  salt  is,  accordingly,  C40  H24  N2  04, 
HO,  S08+  2HO. 
Calculated-  Found. 
III.  IV. 
C40H25N2O5         333    89-3  —  — 
S03  40    10-7        10-7  10-8 
373  100 
I.  II. 
€40H,5N2O8S       373    95-4  —  — 
2HO        18     4-6  4-6  4-6 
891  100 
Jfitrate  of  Silver  and  Quinine.  On  addition  of  nitrate  of  silver 
to  an  alcoholic  solution  of  quinine,  the  formation  of  a  crystalline 
precipitate  takes  place  which,  after  being  washed  with  alcohol,  is 
dissolved  in  boiling  water.  On  cooling,  the  solution  thickens  to 
a  paste-like  mass,  in  which,  after  a  short  time,  small  colorless  crys- 
tals are  formed,  the  liquid  subsequently  becoming  thin,  like  water. 
1*2725  grm.  air-dry  crystals  lost,  at  110°  C,  0*0280  grm.  water, 
or  2*2  per  cent. 
1*4040  grm.  crystals,  dried  over  sulphuric  acid,  lost,  at  110°  C, 
0*0240  grm.  water,  or  1*7  per  cent. 
Ch7635  grm.  salt,  dried  at;  110°  C,  gave  0*1868  grm.  chloride 
and  0-0265  grm.  metallic  silver,  or  21*6  per  cent. 
Consequently,  the  formula  of  the  crystals  is  C40  H24  N2  04-{-AgO, 
N05+HO,  from  which  1*8  p.  c.  water,  and,  in  the  dry  salt,  21*9 
p.  c.  silver  is  reckoned. 
The  crystals  are  sparingly  soluble  in  cold  water  at  15°  C. ;  100 
grm.  water  dissolves  but  0*35  grm.  of  them. 
After  the  settlement  of  the  question  regarding  the  composition 
of  quinine,  it  was  still  uncertain  which  was  its  equivalent.  There 
is  much  inconsistency  displayed  regarding  the  term  equivalent ; 
