ESTIMATION OF SULPHATES. CREIGHTON. 211 



condensation tower ; for if such were the case one would expect 

 to find aluminium hydroxide continually present in the " sul- 

 phur solution " instead of only occasionally. It is important 

 to note that this aluminium precipitate only occurs when the gas 

 contains a large quantity of sulphur, which I may mention is 

 mostly present in some organic form. This consideration leads 

 me to believe that there is probably a connection between the 

 formation of this aluminium hydroxide and the amount of sul- 

 phur, and the condition in which it exists, in the coal; more 

 especially as the Oape Breton coals contain, for the most part, 

 a large percentage of sulphur organically combined, and conse- 

 quently not completely removed in the purification of the gas, 

 while this is not the case with the American co>als referred to. 

 It is hoped in a future paper to give a complete explanation of 

 this behaviour. In conclusion, I would point out the advisabil- 

 ity of using glass balls that are free from aluminium, in deter- 

 mining sulphur in coal gas by the method here described. 



Birmingham University, February 26th, 1909. 



