,236 



CHEMICAL MANUEES. 



cooled by ammoniacal liquor. The condensed ammonia flows into 

 the vessel S, and from there into the collecting reservoir Y. 

 The uncondensed vapours pass through a pipe, traversing the lid 

 of the vessel S into an air refrigerator T. From there into the 

 pipes U, fitted with a safety arrangement, which sends them into 

 an absorption vessel placed behind E. The unabsorbed bad-smelling 

 gases are absorbed by special arrangement. We have followed 

 the progress of the ammonia driven off from the liquid under the 



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Fig. 42. — Mallet's Ammonia Still (front view). 



influence of heat ; let us now follow the inverse movement, i.e. that 

 of the ammoniacal liquor used to feed the stills. This ammoniacal 

 liquor is contained in a reservoir higher up, whence it passes into 

 the measuring vessel G, through tap a ; from that apparatus it first 

 passes into the condenser F, where the steam brought by the coil 

 gives up its heat to it and warms it; the ammoniacal vapours given 

 off rise into G by the pipe P. The stills A, B, C, and D are fed 

 by communication pipes not shown in the illustrations. As already 



