VARIATION OF THE SODIUM-AMALGAM PROCESS 



441 



power of aluminum, however, varies greatly according to the 

 method in which the metal has been prepared. Pure aluminum 

 prepared by the electric method, reduces the nitric acid much 

 less vigorously than the metal prepared by the older methods of 

 fusion with sodium. For this reason the method of Stutzer is 

 not to be preferred to that of Sievert. 



REDUCTION IN AN ACID SOLUTION 



381. Variation of the Sodium- Amalgam Process. This method 

 is described by Monnier and Auriol. 64 



The principle of the operation depends on the reduction of 



Fig. 34. Apparatus of Monnier and Auriol. 



the dissolved nitrate by titrated sodium amalgam in presence of 

 an acid, and the estimation of the quantity of nitric acid present 

 from the deficit in the volume of hydrogen. The apparatus em- 

 ployed is conveniently mounted as shown in Fig. 34. The brass 

 vessel A is movable by means of the cord on the pulley B, in such 



64 Archives des Sciences physiques et naturelles, Gendve, 1894, [3], 

 31 : 352. 



