188 E. DIVEES AND M. OGAWA : 



adopted by Brereton Baker, in his famous experiments upon the 

 non-union of hydrochloric acid and ammonia {J. Cli. Soe.y 1894, 

 65, Gil ; 1898, 73, 422), and we have only dried the gases 

 during their flow through the tubes. As we were able to dry 

 sulphur dioxide better than ammonia, because common phos- 

 phorus pentoxide could be used for the purpose, we have had 

 success in mixing the gases without their combining only by giving 

 this gas precedence. The preparation flask with its tubes having 

 been heated and then kept for a while in the desiccator, was 

 placed in ice and salt while a slow current was sent through it 

 of sulphur dioxide, which had passed through drying- tubes of 

 sulphuric acid and then of phosphorus pentoxide. The outlet- 

 tube dipped into mercury. Ammonia, dried first by the cold of 

 a freezing-mixture and then by long tubes of freshly fused and 

 crushed potassium hydroxide (but no Stas's mixture), was now 

 also passed into the flask slowly. The result was that the in- 

 terior of the flask remained clear for some minutes, the mixed 

 gases only combining on their escape through the mercury into 

 the air. But the ammonia having, it is presumed, gradually 

 brought enough moisture with it through passing more rapidly 

 along the tubes than at first, the walls of the flask became sud- 

 denly coated with an orange-coloured deposit, while the mercury 

 rose high in the exit tube. 



Proportions m which sulphur dioxide mid ammonia combine. 



The proportions, in which ammonia and sulphur dioxide 

 combine, or appear to combine together, depend largely upon 

 the extent to which the temperature is allowed to rise, tlie heat 

 of union being considerable. They vary also according as one 



