i 



ON THE NITROGEN INDUSTRY. 415 



Finally, Kopp Has recently been able, by making use of the difference 

 of the law of thermal variation, lo separate, in the case of platinum 

 iind palladium, the ferromagnetism from the underlying diamagnetism; 

 and tiius to detemiine the atomic moments of these metals. He has 

 found multiples of the magneton. 



The appearance of atomic moments as integral multiples of the same 

 elementarij moment — the magneton — is thus one of the important 

 aspects of magnetic phenomena. 



But in order really to explain the existence of this universal moment 

 it would be necessaiy to be able to link it up with the atom of Eutherford 

 and Bohr and the theory of quanta. Now this theory actually does 

 point to a magnetic moment : 



47r m 



where h is Planck's constant and ejm is the ratio of charge to mass in 

 an electron. But when the calculation is made it is found that the 

 moment derived is almost exactly five times as great as the magneton. 

 The Euther ford-Bohr atom and Planck's theory thus do point to atomic 

 moments which are int-egral multiples of the same elementary moment ; 

 but the magnitude of this elementary moment differs from that derived 

 from observation. It may, therefore, become a question of finding what 

 modification to introduce into the structure of the atom in order to 

 bring about more complete accordance between theory and experiment. 



DISCUSSION ON THE NITROGEN INDUSTRY. 



Dr. J. A. Harker. — Post-^yar Progress in the Fixation of 

 Nitrogen (Abstract). — On the statistical side, there is little to add 

 to the Statistical Supplement to the Eeport- of the Nitrogen Products 

 Committee, whilst the rapid fluctuations in the value of the mark make 

 it useless to discuss the cost of production in Germany. The nitrogen 

 problem has assumed gi*eat pubUc importance, and some acquaintance 

 with it has even been demanded of schoolboys, although five or six 

 years ago ignorance of the subject was great, even amongst those on 

 whom fell the responsibility for decisions of national importance. The 

 literature on the nitrogen question originates, to a greater extent than 

 is usually the case, from prejudiced sources, so that impartial estimates 

 of the relative values of different processes are rarely found. 



"When in Switzerland recently, I met a chemical engineer from 

 Poland, who asked me many questions about the Eeport of the Nitrogen 

 Products Committee. On inquiring of him how he heard of the Eeport, 

 he answered that his attention had been called to it by the managing 

 director of a well-known firm of constructors of chemical plant in 

 Berlin, who told him that in his view it constituted the only presenta- 

 tion hitherto made of the nitrogen problem in its various aspects, in 

 which the difl'erent processes were examined impartially and in detail, 

 and their advantages and disadvantages set foi'th without prejudice by 

 a competent judicial authority. 



