Dr. Herapath on the Cinchona Alkaloids. 59 



if allowed to remain in the mother-solutioa 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 absorl)ent powers also, but very 

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

 spirit, in order to be recrystaUized, 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° 

 Fabr., they lose 5"32 per cent. water = C atoms, and become a dark 

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

 following by analysis : — 



949 100-000 100000 

 and the formula may be provisionally given as — 

 C=^'ff^N-0' 



^J|2SO^HO-^3HO=949, 



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

 less water. 



If this olive-coloured residue be boiled in dilute spirit, the optical 

 crystals deposit on cooling. 



From the addition of 5-32 per cent, water to this dry residue, we 

 find that the silky crystals contain dry residue, — 



94-678=949 = 1 atom 

 Water 5-322= 54 = 6 atoms 



100-000 10f)3 



and we have thus the following formula for the silky salt, which 

 corresponds most closely with the result of analysis, — 



p}'2SOmO-|-9IIO=100;j, 



