NITRATES PROM ATMOSPHERE SCOTT. 



361 



BIRKELAND-EYDE FURNACE. 



This furnace, invented by Prof. Birkeland and Mr. Sam Eyde, 

 of Norway, depends on the inter- 

 action of an alternating-current arc 

 in a constant magnetic field. The 

 furnace, as installed at Notodden, 

 consists of a circular sheet-steel 

 drum about 8 feet in diameter and 2 

 feet wide, lined with refractory fire- 

 brick, and having a disklike space 

 in the center 6^ feet diameter and 

 1^ inches wide. Air is supplied at 

 the center of the furnace by a Root's 

 blower, whilst a channel round the 

 periphery of the disk space carries 

 off the gases and unoxidized air, as 

 shown in figure 1. 



^^ 



flir 

 Inlet 

 < Casii/firouricr 



^ke of Magnef 



Fig. 1. 



Table IV. — Installations for manufacture of calcium cyanamide by the Franck 



and Caro process. 



Name of company. 



Output 



per amiiira 



in tons. 



Nitrogen Fertilizers Co. (North-Westem Cvanamide Co.) 



Do " 



Soeietk. Italiana de Prodotti Azotate 



Society, Italiana per il Carburo de Calcio 



SocietS, Piemontese per il Carburo de Calcio 



Soci^t^ Frangaise pour les Produits Azotes 



Do 



Bayerische Stickstoff Werke 



Ost-Deutscher Stickstoflcalf imd Chemische Werke 



A. G. Stickstoffdimger 



Society, per I'Utilizzazione della Forze Idrauliche della Dal- 

 mazia. 



Do 



Japanese Nitrogen Products Co 



American Cyanamide Co 



Odda, Norway 



Alby, Sweden 



Piano d'Orto, Italy 



Temi, Italy 



San Marcel, Italy 



Martigny, Switzerland. . . 

 Notre Dame de Briancon 



Trostberg, Bavaria 



Bromberg, Prussia 



Knapsack, Germany 



Selenico, Dalmatia 



Dugirat, near Almissa. . . 



Kinzei, near Osaka 



Nashville, Term 



Niagara 



15,000 



15,000 

 4,000 



15,000 

 3,000 

 7,600 

 7,500 



15,000 

 2,500 



18,000 

 4,000 



80,000 

 4,000 

 4,000 



12,000 



tfafer C>reutaHn» 



Two electrodes, one of which is shown in figure 2, project into the 

 center of the furnace and are approached to within about one-third 



inch. They are copper 



tubes, 1^ inches diame- 



,, m ter and five-eighths inch 



1^^ thick, and have water 



f^u>aiMVpitiac6fij>aft ' /Cu in^tctcr circulatiou to kccp them 



Fig. 2. , ^ 



cool. 

 Surrounding the points of the electrodes there is a magnetic field 

 of about 4,500 lines of force per square centimeter. Alternating cur- 

 rent at 5,000 volts and 50 periods per second is supplied to the elec- 

 trodes, and direct current flows around the coils to produce the mag- 

 netic field. 



