376 



Transactions. — Chemistry. 



previously calcined. Morphia and narcotina may be substituted for strycbnia 

 with like results, other alkaloids I have not tried. Those cited can be 

 removed from the absorbent by acids. From the results of numerous experi- 

 ments I find that of all the silicates cyanite and andalusite (pure silicates of 

 alumina) are the most effective absorbents of such bodies. 



The silicates of the alkaline earths, or alkalies simple or compounded either 

 among themselves or with silicate of alumina, appear quite negative to the 

 alkaloids named. Wavellite and anhydrous sesqui-oxide of iron had no absorb- 

 ing power for them. 



These results show that the portion of the clay concerned in the production 

 of the phenomenon instanced is silicate of alumina, and I should conceive a 

 double silicate* to be formed, in every case hydrous, the anhydrous silicates 

 of alumina named passing completely to the hydrous condition when finely 

 comminated and moistened with water as T have previously shown {Trans. 

 N.Z. Inst., Yol. lY., p. 380). 



Akt. LIY. — On the Proposed Substitution of Acetate for Sulphate of Copper 

 in the Manufacture of Iodine. By W. Skey, Analyst to the Geological 

 Survey of New Zealand. 



\^Read before the Wellington Philosophical Society, 23rd October, 1872.] 



The precipitation of iodine from the residual liquors obtained in its manufac- 

 ture is at present accomplished by Soubeiran's method, namely by the addition 

 of sulphate of copper thereto, iodide of copper thus forming and precipitating, 

 but it is found in practice that the precipitation is so incomplete that a 

 notable quantity of iodine remains in solution, necessitating the application of 

 after processes for the more complete removal of iodine from such cupreous 

 liquors. 



In connection with this I would desire to make it publicly known that 

 from certain investigations I have made upon this subject it appears that by a 

 slight modification of Soubeiran's method this loss of iodine may be prevented, 

 or so nearly that the necessity of after processes will be avoided. 



The particular agents most active in causing this retention of iodine in the 

 liquor are sulphate of copper, free sulphuric acid, and alkaline sulphates and 

 chlorides, since they exercise a considerable solvent action upon the iodide of 

 copper formed in Soubeiran's process. 



* Since the communication of this paper I find that silica chemically prepared and 

 rendered anhydrous by heat will also absorb strychnia from aqueous solution, clearly 

 showing that at any rate single silicates of the alkaloids readily form. 



