FIXED NITKOGEN RESEAKCH LABORATORY. 505 



study to this phase of the general problem, partly because its ade- 

 quate study involves a very considerable excursion into the theory 

 and practice of internal-combustion motors. The strengthening of 

 our engineering division this year will greatly facilitate the handling 

 of such problems. 



NITRIDES. 



The fixation of nitrogen in the form of various nitrides has also 

 occupied the attention of the laboratory this past year, but as yet 

 nothing very definite has developed to indicate that this field holds 

 out especial promise from the standpoint of self-contained fixation 

 processes. The best immediate chances here would seem to lie in 

 the possibility of combining nitrogen fixation with the preparation 

 of some other valuable product; e. g., some of the modifications of 

 the Serpek process, where the formation of aluminum nitride serves 

 not only as a step toward fixing atmospheric nitrogen as ammonia, 

 but also to prepare pure alumina from crude ore and possibly even 

 admit of using as ore material not now considered available, such 

 as bauxites running too high in iron for present processes. 



NITROGEN FIXATION BY ORGANISMS. 



Nature's own most important channel for fixing atmospheric nitro- 

 gen and storing it up in our soils is undoubtedly the action of certain 

 living organisms of which several species of bacteria are the best 

 known. Much has been done both in the study of the best field con- 

 ditions to favor these natural processes, as well as in attempts to 

 cultivate specially active strains of the organisms and inoculate 

 roots with them. This side of the problem falls more properly, 

 however, within the province of the Bureau of Plant Industry and 

 the Fixed Nitrogen Research Laboratory has therefore not concerned 

 itself therewith. 



There is, however, one aspect of the problem which directly inter- 

 ests this laboratory, and that is the question of the chemical mechan- 

 isms by which the organisms effect the fixation. These are of 

 special significance, because aside from the combination with metal- 

 lic lithium to form nitride, they appear to be the only positively 

 established reactions of free nitrogen which proceed with measurable 

 speed at ordinary temperatures. Could we discover just what class 

 of compounds the bacteria use in thus operating on free nitrogen at 

 these low temperatures, it might be the clue to a whole new chapter 

 of nitrogen fixation on the industrial scale. Studies in this general 

 direction are being undertaken by the laboratory with the coopera- 

 tion of the Bureau of Plant Industry, but due to the intrinsic diffi- 

 culty of the subject, the work is apt to go slowly even under the most 

 favorable conditions. 



A COMPREHENSIVE SUMMARY. 



Report on the Fixation and Utilization of Nitrogen, Nitrate 

 Division, Ordnance Office, War Department, Document No. 2041, in 

 cooperation with the Fixed Nitrogen Research Laboratory. (This 

 report covers the subject in considerable detail and contains a chapter 

 dealino- with the accomplishments of the Fixed Nitrogen Research 

 Laboratory from date of establishment up to 1922. This report can 

 be purchased from the Superintendent of Documents, Government 

 Printing Office, Washington, D. C, for 50 cents.) 



