246 



AMINES. 



a curved glass point d. About 6 cc. of a concentrated aqueous 

 solution of nitrite of potassium (free from carbonate), together 

 with nearly an equal quantity of water, is introduced into the 

 generating vessel. The lower parts of the funnel-tubes, that is 

 up to a little above the tap, say about e t are also filled with water, 

 so as to displace the atmospheric air. Dilute sulphuric acid is 

 now poured into one funnel, and a weighed quantity of the amide 

 dissolved in water into the other, taking care not to allow any 

 lulUes of air to adhere to the sides. 



Fig. 11. 



The atmospheric air in the apparatus has now to be displaced, 

 and this is effected by running sulphuric acid, little by little, into the 

 nitrite solution, by which nitrous acid and nitric oxide are evolved. 

 To ascertain if the displacement is complete, 5 to 10 cc. of the gas 

 from the generating vessel are allowed to pass into the measuring 

 tube (Fig. 11) previously filled with solution of ferrous sulphate. 

 Not more than 0*1 cc. should remain unabsorbed. Fresh iron- 

 solution may be introduced, if necessary, from the flask B, as sub- 

 sequently described. The apparatus is now ready for the com- 

 mencement of the actual experiment. The measuring-tube, stand- 



