155 



in the minimmu (juanlit} of water, acidulated with sulphuric acid. 



This acid alkaloidal solution vv^as washed repeatedly with ether 

 until the latter removed no more colouring matter. The solution 

 was then rendered alkaline and again shaken with ether; the 

 ethereal solution was separated and evaporated to dryness and the 

 residue was again treated in the way described above, in order to 

 obtain the alkaloid finally in as pure a condition as possible. 



This dry alkaloid, which had been purified several times, was 

 now dissolved in water containing a trace of hydrochloric acid, and 

 the faintly acid solution was evaporated to dryness in a dessiccator ; 

 the residue was dissolved in a few drops of water, and after 

 filtration the solution w^as placed on a microscope slide. 



A platinum wire which had been moistened with a solution of 

 sodium tartrate, was placed in the previously warmed solution and 

 the latter was allowed to cool slowly under a double watchglass. 



After some time needles separated (fig. 1). 



These needles could be : quinine tartrate, cinchonidine tartrate or 

 a mixture of the two. 



In order to determine whether we were indeed concerned with 

 quinine, the needles were washed a few times very carefully with 

 a little water, so that they remained on the slide. 



Then a trace of dilute sulphuric acid was added and a little of 

 a mixture of equal parts of alcohol, of water, and of acetic acid 

 coloured pale yellow by means of a potassium triiodide solution. 

 After a short time there appeared at the edges of the preparation 

 the very fine dichroitic leaflets of HI iodine-quinine sulphate (fig. 2), 

 a reaction which is so characteristic of quinine, that the presence 

 of this alkaloid in the seed of C. lechjeriana can no longer be 

 doubted. 



Finally I may add that the seed investigated contained 18.6 7o o^" 

 a pale greenish yellow oil, having a specific gravity of 0.930 at 

 18° and a rotation of —26^ at 20^ C. in a tube of 20 cm. 



Physics. — ''T lie red lithium line and the spectroscopic determina- 

 tion of atomic iveights." By Prof. P. Zeeman. 



In a former communication I showed that the red lithium line 

 6708 is a close doublet. The distance between the components was 

 found by a rough measurement to be of the order of a quarter 

 Angstrom. I now have been able to photograph the mentioned line 

 in the second order spectrum of a large Rowland grating. Using an 

 iron-arc spectrum in the third order violet, coinciding with the 



