abstracts: chemistry 203 



CHEMISTRY. — The iodometric determination of sulfur dioxide and the 

 sulfites. John B. Ferguson. Joiirn. Amer. Chem. See. 39: 364- 

 371. March, 1917. 



In this paper are presented and discussed the results of an investi- 

 gation of the various iodometric methods for the determination of 

 sulfur dioxide and the sulfites. The object of this investigation was 

 threefold: (1) To ascertain the limitations of the existing methods and 

 procedures; (2) to determine the important sources of error; (3) to 

 develop, if necessary, procedures suitable for general application. 



Sulfur dioxide. Of the methods considered, the excess iodine is 

 suitable for the analysis of mixtures of either high or low sulfur-dioxide 

 content; the Selby Smelter Commission method is suitable for mixtures 

 of low sulfur-dioxide content; the Reich method gives only approxi- 

 mate results unless large samples are available; and the sulfite method 

 must not be used without a correction factor. Two precautions are 

 essential: (1) The gas sample must not come in contact with even a 

 trace of moisture prior to reaching the absorbent; (2) the analj'^zing 

 apparatus must be free from rubber connectors if mixtures containing 

 2 per cent or more of sulfur dioxide are to be analyzed; and rubber 

 connectors would best be eliminated altogether. The excess iodine 

 method is recommended. 



Sulfites. In the Tread well method errors due to the oxidation of 

 the sulfite solution arise from various sources and to eliminate them 

 the following procedure is recommended: The solid salt is dissolved 

 directly in an excess of an iodine solution containing sufficient hydro- 

 chloric acid, and the excess iodine determined with thiosulfate. 



J. B. F. 



CHEMISTRY.— T/i£' ternarij system H20-K2SiOz~Si02. George W. 



MoREY (Chemical Study) and C. N. Fenner (Microscopic Study). 



Journ. Amer. Chem. Soc. 39; 1173-1229. June, 1917. 

 The ternary system H20-K2Si03-Si02 has been studied over the 

 temperature range 200° to over 1000°. The work comprises a deter- 

 mination of the composition and properties of the various stable soli|^ 

 phases which can coexist with solution and vapor within the above 

 temperature range, of the composition of the solutions in equilibrium 

 with the solid phases, of the change in composition of these solutions 

 with temperature, and the approximate determination of the corre- 

 sponding 3-phase pressures. The chief experimental method used was 

 an adaptation of the "quenching" method so extensively used in the 

 Geophysical Laboratory for the investigation of dry melts. 



