FIXED ISriTEOGEiSr RESEARCH LABORATORY. 497 



Processes may conveniently be recognized as naturally falling 

 into three categories, viz: (1) Processes which have attained a posi- 

 tion of industrial importance, but from intrinsic limitations are 

 apparently already past their zenith and doomed to displacement by 

 more economical processes. (2) Processes already closely competing 

 with those of class 1 and which present manifest opportunities for 

 further fundamental improvements looking to cost reduction. (3) 

 Processes not yet industrially competing with class 2, but out of which 

 it seems possible that something still better may ultimately come. Of 

 course, we must not expect to fit any particular process too exactly 

 into the above classification; also, processes totally unsuited to the 

 bulk of industrial production may prove the key to important 

 special situations. 



At the time of our entry into the war the three processes of nitrogen 

 fixation claiming most attention for Government-built plants were 

 the electric arc, the cyanamide, and the direct synthetic ammonia 

 (Haber). Of these, the arc was quickly placed in class 1 on account 

 of its very high power requirement. 



The cyanamide process, which had definitely crowded the arc 

 process out of class 2 because of the former's threefold greater 

 energy, economy, and adaptabilit}' of products, was already recog- 

 nized to have reached its probable Imiiting efficiency. 



Even at that time there was much to indicate that the direct syn- 

 thetic ammonia process, which was already operating on a commer- 

 cial scale in Germany, would eventually displace the cyanamide 

 process, just as this had displaced the arc process, and primarily for 

 the same reason, viz, its smaller power requirements. The direct 

 sj'nthetic ammonia process was, however, still very new and wholly 

 untried on a commerciaL scale outside of Germany. For this reason 

 it was decided to put the main reliance for war purposes in the 

 cyanamide process, which, though intrinsically more expensive on 

 account of its larger power requirements, could be installed with 

 absolute certainty of its working smoothly from the start, which 

 could not be said at that time for the direct synthetic ammonia 

 process, due to the more intricate character of its equipment and our 

 lack of knowledge and experience concerning it. 



CYANAMIDE. 



During the first two 3^ears, while the laboratory was still under the 

 War Department and it was felt that the cyanamide plant at Muscle 

 Shoals inight at any time be called upon to start up under Govern- 

 ment operation, the laboratory's attention was naturally directed 

 largely to problems connected with the peace-time operation and 

 possible improvement of the cyanamide process. These studies, 

 while furnishing valuable data against the time of possible further 

 operation of the large plant, have also confirmed the idea that the 

 best chances for making further decisive cuts in the cost of nitrogen 

 for fertilizer purposes lie along the lines of other processes. 



During the past fiscal year additional data have been secured on 

 the stability of calcium carbide at high temperatures, and upon the 

 mechanism of the nitrification of carbide. In connection with this 

 work a very accurate method for the determination of calcium car- 

 bide has been developed. 



