638 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



process has been in commercial operation much longer than the 

 synthetic ammonia process, and consequently is in a much higher 

 state (»t' development. 



The laboratory has made a rather critical study of the present form 

 of the process, from Avhich it appears that improvements leading to 

 a drastic reduction in the cost of operation are rather improbable. 

 The process requires a relatively large amount of electric power for 

 the manufacture of carbide, and hence cheap power is necessary to 

 its profitable operation. Since the manufacture of carbide is now 

 a standardized process, the possibility of materially reducing the 

 power requirements seems somewhat remote. The nitrification of 

 carbide, the second step in the process, is about 85 per cent efficient 

 in the best commercial practice and hence offers some opportunity 

 for improvement. During the past year experimental studies have 

 been undertaken on the fundamental reactions involved in this 

 process for the purpose of determining how improvements might be 

 advantageously made in the present form of the process, as well as 

 to obtain data" which may suggest a modification leading to a reduc- 

 tion in cost of operation. Important data on the formation and 

 decomposition of cyanamide have ah-eady been obtained, but further 

 study is required to complete the investigation. Researches of this 

 character, as well as those mentioned later in connection with the 

 cyanide process, should throw much light on the reactions of free 

 nitrogen to form cyanamide. cyanides, and nitrides." 



ARC PROCESS. 



The arc process is the oldest and, in many respects, the simplest of 

 the three commercially developed methods of nitrogen fixation. It 

 has the very important advantages from a military standpoint that 

 it can be rapidly installed in case of war, and that it provides nitro- 

 gen directly in the nitrate form. Since the Government does not own 

 an arc plant, the laboratory has given much less attention to this 

 process, for the time being, than to the other processes. The experi- 

 mental studies have been confined largely to the fundamental theory 

 of chemical reactions in the j^ath of the electric discharge. 



During the past year the laboratory made a rather critical survey 

 of the present form of the process, with a view of ascertaining the 

 nature and extent of the improvements which can be made. The 

 resuhs of this study are given in the " Report on the fixation and 

 utilization of nitrogen." The study showed, in particular, the neces- 

 sity of improving the method of nitrogen-oxide recovery and of 

 increasing the efficiency of furnace operation. Experimental studies 

 made in connection with nitrogen-oxide recovery are briefly described 

 in a later section of this report. To materially increase the energy 

 efficiency of the process, Avhich at the present time is very low, a 

 more accurate knowledge of the reactions occurring in various types 

 of electric discharge is absolute^ essential. In this connection a 

 study was made of the production of ozone by the corona discharge 

 and the production of active nitrogen in the low-pressure arc and in 

 an electrodeless discharge. A number of physical and chemical 

 properties of these two highly interesting and important substances 

 were also determined. Investigations of reactions in the path of 



