THE discussion on the nitrogen industry, organised by Section B (Chemistry) of the British Association at the Hull meeting, proved to be a great success in spite of certain obvious difficulties in the way of such a discussion at the present time. There are many processes in the field for the fixation of nitrogen, and commercial rivalries make it impossible to secure completely frank and unbiassed accounts of the merits of the various systems. Much information of great scientific value has, for commercial reasons, to remain unpublished. The Section was therefore fortunate in obtaining a general survey of the subject from Dr. J. A. Harker, whose experience in this field during and since the war was exceptionally great, his practical acquaintance with most of the competing processes enabling him to take an impartial view of many controversial matters. His paper makes it easier for chemical readers to judge of the value of statements appearing in the technical periodicals and in the popular Press. According to Dr. Harker, there is little to be added in the way of statistical material to the Report of the Nitrogen Products Committee published some eighteen months ago, while the fluctuations in the German exchange make it quite unprofitable to discuss German conditions of production or the possibility of dumping, topics which would otherwise have been attractive to the author of such a paper. The nitrogen question has attracted so much public attention that it has even found its way into school examination papers, although profound ignorance on the subject prevailed five or six years ago, not only among the general public, but also in the circle of high officials directly concerned with questions of national importance.