Moody — Iodometric Determination of Basic Alumina. 487 



Differential iodine (if negative.) 



(102*2 \ 

 ) (0-134) = basic alumina. 

 6X12 6-9/ v ' 



The results of analyses of four specimens of alums are given 

 in the following table : 









Table. 













Percentage composition. 











A1 2 3 













, 



x .. 



— , 







Insoluble 





Total. 



Combined. 



Basic. FeO.* 



ZnO. 



NH 3 . 



material. 



No. I 















(1) 



14-48 



13-49 



0*99 0-43 



3-70 



none 



0-61 



(2) 



14-28 



13-46 



0-82 0-44 



3-70 



none 



0-61 



No. II 















0) 



15-94 



14-21 



1-73 0-43 



1-47 



none 



0-21 



(2) 



15-90 



14-34 



1-56 0-45 



1-34 



none 



0-21 



No. Ill 















(1) 



15-59 



1481 



0-78 0-34 



0-73 



none 



0-71 



(2) 

 D. 



(1) 



15-97 



14-80 



1-17 0-36 



0-82 



none 



0-71 



16-59 



15-24 



1-35 0-24 



0-11 



none 



0-61 



(2) 



16-37 



15-18 



1-19 0-24 



0-19 



none 



0-61 



The writer wishes to thank Prof. F. A. Gooch for sugges- 

 tions of procedure during the investigation. 



*A trace of iron in the ferric state was found present in each sample. 



