1863.] 417 



characterize them as para-compounds of the amyl-lepidyl-ammonium 

 salts, but I am far from attributing to these formulae any other 

 value. In fact the molecular construction of this new class of 

 compounds remains to be established by further experiments. 



The theory which (in 1852) satisfactorily represented the consti- 

 tution of the nitrogen bases then examined, requires an expansion to 

 include the tinctorial ammonias added to our knowledge during the 

 last decade. The time for the enunciation of this amplified theory 

 has not yet arrived. 



Here only a few experiments may still be mentioned, which were 

 made with the oxide corresponding with the salts described. 



The action of oxide of silver upon the iodide dissolved in alcohol 

 liberates the base, which, on evaporation of the alcohol, separates as 

 an indistinctly crystalline deep-blue mass, moderately soluble in water, 

 less soluble in anhydrous ether, easily soluble in alcohol. Ether 

 precipitates the base from its alcoholic solution ; I have not exa- 

 mined it. 



Submitted to distillation, the free oxide gives rise to an oily base, 

 which I naturally expected to be lepidine ; but the experiments which 

 I have hitherto made with this substance appear to negative this 

 assumption. I have undertaken a more minute examination of the 

 compound, because, if it be different, its study will probably throw 

 some light upon the still uncertain constitution of the tertiary bases 

 of the chinoline series, which I have frequently attempted to decipher. 

 It remained now only for me to examine the mode of formation 

 of the remarkable compound the nature of which I have endeavoured 

 to clear up. With this view I have studied the action of iodide of 

 methyl and amyl upon chinoline and lepidine, large quantities of 

 which were kindly placed at my disposal by my friend Mr. David 

 Howard. The products obtained in this reaction I have not sub- 

 mitted to a minute examination, having satisfied myself that their 

 principal phases are well illustrated by the equations which I have 

 given for the formation of the substances produced by the action of 

 iodide of amyl upon lepidine. Nor have I followed out in detail the 

 complicated secondary changes, and more especially the generation 

 of the red colouring matter which is abundantly formed in these 

 reactions. I have nothing to add to the perfect description of these 

 phenomena by the distinguished discoverer of this pigment. 



