320 



5th. The modification which it undergoes by resolution or recry- 

 stallization, and the formation of a salt more resembling the garnet- 

 red iodo-sulphate, but having strongly marked differential characters 

 from this beautiful salt, viz. its strong tourmaline powers of absorp- 

 tion and its deeper colour, being nearly a brown- purple, and by its 

 disposition to assume the rhombohedric form. 



The author has not yet analysed this salt, but hopes ere long to 

 accomplish this matter and communicate his results to the Royal 

 Society ; but he ventures to hope that it will be found to contain 2 

 atoms sulphuric acid and 3 atoms iodine, like the analogous quinine 

 and cinchonidin salts. 



The author has also assured himself that there is an analogous 

 class of salts produced by ethyle-quinine and ethyle-quinidin, but 

 optically distinct from those of quinine and quinidin. He has already 

 produced three salts from ethyle-quinine, having optical characters 

 different from any previously described. 



1st. A deep purple-red salt by transmitted light, in thicker plates 

 or aciculse quite impervious to light. This salt occurs as very slender 

 acicular prisms ; it has a brilliant metallic-green reflected tint, but 

 very little double absorption. 



2nd. There is a foliaceous salt, having a plate-like form, a deep 

 red or orange-red colour, transmitting an orange-yellow, having only 

 slight optical powers. 



3rd. A salt having many of the characters of the new quinidin 

 salt when first produced, viz. the optical characters and the a- form ; 

 but on attempting to recrystallize it, the orange-red plates just de- 

 scribed are alone produced. 



The only salt yet produced from ethyle-quinidin is one very similar 

 to the red salt described above, but it has only been very partially 

 examined. The iodide ethyle-quinidin is a very beautiful silky salt, 

 less soluble than the iodide ethyle-quinine. The author is not aware 

 that it has yet been described. It is readily made by mixing an 

 alcoholic solution of quinidin with an etherial solution of iodide- 

 ethyle ; on repose, the new iodide ethyle-quinidin separates in long, 

 slender, silky aciculse; and further crops can be repeatedly pro- 

 duced by diluting the original solution with water until precipitation 

 begins to follow ; on long repose, the iodide crystallizes and may be 

 removed by filtration, and washed with dilute spirit. 



