Decembee 18, 1914] 



SCIENCE 



903 



removal of crops. In this way the percentage 

 of the crops that can be removed from the 

 soil will be very much greater than under pres- 

 ent conditions. 



The cheapening of nitrogen fertilizers will 

 permit of doubling, trebling or even more 

 greatly increasing farm crops. In addition 

 to these results cheap nitrogen fertilizers will 

 permit a very much greater percentage of 

 crops to be removed from the farms. Cheap 

 nitrogen fertilizers will also permit of the most 

 intensive farming in the immediate vicinity 

 of industrial centers, thus lessening the time 

 and cost of food distribution. 



Surely the problem of nitrogen fixation 

 should appeal to every one interested in the 

 conservation of our resources. Our waterfalls 

 represent an equivalent of nitrogen salt con- 

 tinuously going to waste instead of being used. 

 And surely work of this kind is of greater 

 importance than the building of dreadnaughts 

 or the training of armies. 



W. W. Strong 



G ABB AGE INCINEBATOS AT BABMEN, 

 GEBMANY 



Owing to the great distance garbage had to 

 be hauled for dumping, the city of Barmen, 

 numbering 1Y2,000 inhabitants, formerly ex- 

 perienced considerable difiiculty and incon- 

 venience in disposing of its refuse and waste 

 matter, and finally decided to build a garbage 

 incinerating plant where waste material of all 

 sorts is now burned. 



The plant was constructed in 190Y and has 

 given excellent satisfaction in every partic- 

 ular. Not only is all city garbage disposed of 

 in a sanitary way, but from the cremation of 

 this waste two important products are gained, 

 an excellent quality of sand, and electricity. 



The city's garbage is collected by an aver- 

 age of twenty wagons, which convey the same 

 to the incinerator and there dump it into large 

 bunkers measuring 4 X 12 meters (floor space) 

 each. There are seven of these bunkers, each 

 having four trapdoors to receive garbage. 

 From the bunkers the garbage is carried on 

 wheelbarrows to huge funnels which feed the 

 furnaces where the refuse is burned. These 



funnels have a capacity of 1,200 lbs. each and 

 they are also seven in number. After being 

 filled, a large plug in the center of the funnel 

 is raised and the garbage falls through the 

 opening beneath into the furnace, where it 

 remains for an hour. During the first half 

 hour it rests in the rear of each furnace, 

 where it is ignited by the former deposit, and 

 after burning for half an hour it is brought 

 to the mouth of the furnace by large iron 

 scrapers manipulated by the men serving the 

 fires, and there remains the rest of the hour, 

 cooling and igniting the next deposit from 

 the funnel. 



The garbage is then in the form of a glow- 

 ing, molten mass, called slag, which is removed 

 from the furnaces with long iron hooks and is 

 pulled directly from the grate into metal 

 wheelbarrows, to be then wheeled to the 

 sprinkling quarter, where the redhot slag is 

 cooled by means of water sprinkled thereon 

 for fifteen minutes. Later this process will be 

 simplified, the slag being dipped into reser- 

 voirs instead of sprinkled. 



After N sprinkling, the slag resembles large 

 clinkers and these now come to the crusher 

 where they are broken, ground, and finally 

 reduced to various grades of sand which is 

 used with splendid results for building pur- 

 poses and for the construction of bricks. 



While the garbage itself is thus reduced to 

 sand, the burning of the same gives another very 

 valuable product, namely electricity. This is 

 manufactured in the following manner. The 

 gases resulting from the burning of the gar- 

 bage have a temperature of from 1,200 to 1,500 

 degrees Celsius. These gases are conducted to 

 two boilers and there utilized in the produc- 

 tion of steam, the latter having a pressure 

 of 10—12 atmospheres. Normally steam of this 

 pressure has a temperature 180° Celsius, but 

 in this case the steam is superheated until its 

 temperature is 300° C, in order that it may 

 be perfectly dry and there may be no danger 

 of its injuring the turbine to which it is now 

 conducted. This steam turbine is a 600 h.p. 

 machine of 3,000 revolutions per minute, and 

 its axle is directly united with that of the 

 dynamo. The capacity of the latter is 400 



