FIXATION OF ATMOSPHERIC NITROGEN 97 



Samuel Eyde. In this drum the air is submitted 

 to a temperature of 3,000 C. By rapid cooling 

 the nitrous oxide (NO) formed in the electric 

 flame is retained almost entirely, while in former 

 processes it was in great part lost. The nitrous 

 oxide issuing from the furnace at a tempera- 

 ture of 600 to 700 C. combines with the oxygen 

 to form N02, which is passed through a series 

 of towers. It finally yields nitric acid of 50 per 

 cent strength, which is saturated with lime. 

 The mass is heated to 450 C., which is its 

 melting point, then poured into cast-iron cylin- 

 ders, where it solidifies slowly. In the beginning, 

 crystallized nitrate of lime was manufactured 

 and was difficult to use owing to its hygroscopic 

 properties. This product melted between the 

 fingers and thus could only be used mixed 

 with peat dust. That was why manufacturers 

 afterwards set themselves to make basic nitrate 

 of lime; but this product contains only 11.7 per 

 cent of nitrogen, which rendered its freight 

 charges heavy, and formed an obstacle to its 

 sale. Lately, the partially dehydraded salt 

 tested 13 per cent of nitrogen. The first manu- 

 factory of any importance of this product was 

 built at Notodden in Norway. The experience 

 acquired in that factory has induced the manage- 

 ment of the company to increase the plant, 

 so as to make 8,000 to 10,000 tons per annum. 

 This factory is maintained by the Badische 

 Anilin und Sodafabrik. The unit of nitrogen 



