The Influence of Aluminium Salts on the Estimation 

 OF Sulphates. — By H. Jeemain M, Creigiiton^ M. A., 

 Birmingham University, Birmingham, England. 



Read 24th April, 1909. 



During an experience extending over three years, in the 

 estimation of sulphur in coal gas, the writer at various timer 

 observed the presence of a flocculent white precipitate in the 

 liquid which resulted from the condensation of the vapours 

 formed by the burning of the gas. The following investigation 

 was therefore carried out with a viev/ to determining the 

 nature of this precipitate and the influence its presence had 

 on the estimation of the sulphur present in the liquid. It 

 may be mentioned here that the amount of sulphur in coal gas 

 was determined by burning a known volume of the latter in a 

 special burner which was surrounded with lumps of ammonium 

 carbonate. Over the burner fitted a large glass tube, up which 

 the. gases of combustion passed into a glass tower filled with 

 glass balls. On coming in contact with the cold balls, the sul- 

 pluir dioxide, ammonia, water vapour, etc., condensed and were 

 caught in a beaker placed beneath the tower. After oxidation, 

 the sulphur in this liquid was determined by precipitation with 

 barium chloride. It was in this liquid which I shall refer to as 

 the " sulphur solution," that the white flocculent precipitatf 

 referred to was frequently obsen'ed. 



It should be pointed out that the coal from which the gas 

 WRS generally made was that supplied by the Dominion Coal Co., 

 in Cape Breton; and that analysis showed it to be very often 

 high in sulphur. On several occasions where different American 

 coals low in sulphur were used, no such precipitate occurred. 



This white precipitate readily dissolved in dilute hydro- 

 chloride acid, and was re-precipitated by ammonium hydroxide 



(207) 



