230 chp::\iical manures. 



2. Bourgeois and Lencauchez' Process. — Bourgeois and Len- 

 cauchez have patented a process the object of which is to collect 

 the tar and ammonia in the gas distilled from coal, this operation 

 not diminishing the calorific intensity of the gas. The plant which 

 they propose to use therefore appeals to all industries, glass 

 works, metallurgical industries, etc., which instead of burning coal 

 under ovens, begins b}" converting it into gas in any kind of 

 gas producer. It consists of three main columns. The first, cooling 

 and washing the gases, is intended to retain tar and oils, which 

 are collected in a lower cistern. In the second, the gas charged 

 with ammonia meets a shower of acidulated water. The third is 

 intended to stop the last traces of ammonia and to convey them into 

 the first, and so on. From the preceding it will be seen that those 

 industries which formerlv did not utilize in anv wav the nitrosren 

 contained in their fuel, are gohig to become one of the most import- 

 ant sources of ammonia. 



Minufacturing Plant. — In the various ammonia-producing 

 industries which have just occupied our attention, the manu- 

 facturing plant consists, above all, of condensers and distilling 

 columns. 



Condensers. — The condensers are generally refrigerators, the 

 extractor, the washing condenser of some kind of system, and the 

 scrubbers, or coke columns. Refrigerators are used in the manufac- 

 ture of gas. The issuing gas is aspirated by the extractor, which is 

 nothing but a suction and pressure pump. There exist a certain 

 number of washing condensers. The following are mentioned : 

 The Standard washer, the Chevalet washer, the Lunge Plate washer, 

 the Pelouze and Audoin washer. The Standard washer consists of 

 a series of cast-iron compartments, variable in number and dimen- 

 sions according to the capacity of the plant. Each compartment 

 contains a certain number of wrought-iron discs bolted together 

 and locked on the shaft. These discs of thin sheet-iron, 2 to 3 mm. 

 (yV ^o \ inch), thus present an enormous absorption surface. The 

 latter traverses the washer in an opposite direction to the gas ; the 

 discs half dip into the water. An improvement has been made by 

 replacing the sheets of iron by pieces of wood, cut in the form of 

 a prism and arranged in quincunxes. This apparatus is almost ex- 

 clusively used in Great Britain. The washers restore to the scrubbers 

 their true role, which is to arrest the last traces of ammonia. The fill- 

 ing of the scrubbers varies much ; sometimes washed coke is used, 

 sometimes wood shavings, fragments of pumice stones, or of perfor- 

 ated bricks. The lining ought to be done carefully, for on it gi'eatly 

 depends the amount of water to be introduced. A driblet of water, weU 

 spread over well-arranged materials, will give as good an exhaustion 

 as enormous quantities of water over a bad lining. The water 

 escaping from the scrubbers should be carefully controlled. The 



