14 



which probably give the following formula :- 

 C 57 H 33 N 2 



One other remarkable difference exists between the quinine and 

 cinchonidin salt, which is, that the optical crystals of the last salt, 

 if allowed to remain in the mother-solution with an excess of less 

 than 1 per cent, of sulphuric acid, undergo a transformation, and 

 become long, golden, silky aciculse, radiating in beautiful globose 

 tufts : this salt has some doubly absorbent powers also, but very 

 feeble. When this salt is attempted to be redissolved in boiling 

 spirit, in order to be recrystallized, it does not re-form, but the 

 optical crystals are then produced ; when the silky crystals are 

 carefully air-dried, they retain their yellow colour, but if exposed 

 over sulphuric acid at 62 Fahr., or if attempted to be dried at 212 

 Fahr., they lose 5'32 per cent, water = 6 atoms, arid become a dark 

 greenish-black residue, which is a tri-hydrate and contains the 

 following by analysis : 



I. II. III. IV. 



Iodine 40'504 40*407 



Sulph. acid 9064 8'324 



Carbon . . 36-082 35*689 



Hydrogen 36-404 36-28 36-583 



numbers which very closely correspond with the following : 



949 100-000 100-000 



and the formula may be provisionally given as 



C 57 H 33 N 2 O 5 1 



J2SO 3 ,HO + 3HO=:949, 



which closely corresponds with the optical salt, but contains 2 atoms 

 less water. 



