NITROGENOUS MANURES. 247 



passes from the top of the furnace into the distilHng zone, where it 

 is dried and then heated to convert it into a sort of coke. The gases 

 produced charged with steam ammonia and tar pass into h. The 

 barred grate C enables the admission of the incandescent coke into 

 the zone of combustion to be regulated — a real furnace, where the 

 peat burns before passing to the ash-pit. The ammoniacal gases, 

 dry and very hot, pass out by the pipe utilized as a heating surface 

 for the concentration of the ammoniacal liquors. Dampers F as 

 well as shaking grates C and E enable the progress of the combus- 

 tion to be regulated. 



Been Iteration of the Ammonia. — For the manufacture of fertilizers 

 it is advantageous to substitute for simple condensation a method 

 of fixing the ammonia in a form immediately utilizable as a manure. 

 The porosity of peat gives it a considerable absorptive capacity. 

 Bacqua and Lorette use it to absorb the ammonia from the distilla- 

 tion gases. These pass into chambers containing perforated boxes 

 arranged as bafHes and filled with a mixture of peat, sawdust, and 

 sulphuric acid, and are there deprived of all their ammonia. 



Gaillot and Brisset use pure peat impregnated with acid solutions 

 or mixed with superphosphate of lime as an absorbent. Their re- 

 cuperator (Fig. 49) consists of a tower K, divided into ten stages by 

 wide oscillating flat bars driven independently, so as to be able to 

 regulate from the outside the forced methodical circulation of the 

 absorbent of whatever nature it ma}^ be. The arrivals respectively 

 of the hot and cold gas produced in their ovens already described 

 are in G and H at heights calculated so that the space H I is 

 sufiicient for the gases escaping by the chimney I not to contain 

 more than traces of ammonia, and that the path G H suffices to dry 

 perfectl}^ the manure reaching the discharge door of the oven L. 



Muntz and Girard collect ammonia by condensation and 

 bubbling, purify the ammoniacal liquors by distillation, then treat 

 them by NaCl. Ammonium chloride and insoluble bicarbonate of 

 soda are obtained ; the carbonation is finished bv a current of carbonic 

 acid from the residual bicarbonate, then it is filtered. The calcina- 

 tion of the product enables the ammonia to be recovered, and gives 

 COo utilized for the next carbonation. The filtered solution con- 

 tains an excess of NaCl and ammonia, as ammonium chloride and 

 carbonate. The carbonate is separated by distillation, and calcined 

 at a higher temperature. NaCl equally soluble in the hot state as 

 in the cold crystallizes ; it is separated, and there is finally obtained a 

 very concentrated solution of ammonium chloride, which is crystal- 

 lized. The product may afterwards be refined or used directly as 

 manure. 



Manufactiire of Sidphate of Ammonia from Peat by the Mond 

 Process. — After numerous unfruitful experiments on the utilization 

 of peat, Dr. Caro has applied the Mond process, by which poor coals 



