210 



INFLUENCE OF ALUMINIUM SALTS ON THE 



TABLE 2. 



From the foregoing results, it is seen that the effect of the 

 presence of small quantities of aluminium chloride is to produce 

 a material increase in the weight of the barium sulphate pre- 

 cipitate. With increasing amounts of aluminium chloride and 

 a constant amount of sulphate present, the weight of aluminium 

 taken up by the barium sulphate at first increases and then 

 remains constant, while in the second case, where the amount 

 of sulphate is varied, the degree of contamination of the barium 

 sulphate is proportional to the weight of sulphate used. These 

 results are similar to those obtained by Schneider* for iron. In 

 a solution containing 0.5 gram of ammonium sulphate and 0.025 

 gram of aluminium there would be an error of about 1 per cent, 

 in the estimation of the sulphur present, as carried out in the 

 ordinary way. 



Although it is well known that ammonium carbonate cannot 

 be kept in clay or stoneware jars on account of its action upon 

 them, the presence of ammonium carbonate round the gas burner 

 is not sufficient to explain the corrosion of the glass balls in the 



*Schneider, E. A., Zeit. f. physik. Chem., 1892, 10, 425 



