August 30, 1919] 



SCIENCE 



209 



•which, was recently established at the Utah 

 Agricultural College and Experiment Station. 



M. E. Geabee, professor of mathematics at 

 Heidelberg University, has been appointed pro- 

 fessor of physics at Morningside College, Sioux 

 City, Iowa. 



De. S. I. KoENHAuSEE, formerly associate 

 professor of zoology at Northwestern Univer- 

 sity and recently relieved from duty in the 

 Sanitary Corps of the Army, has been ap- 

 pointed acting professor of zoology at Deni- 

 son University in the absence of Professor 

 Fish. 



M. Paul Appell, dean of the faculty of sci- 

 ences, Paris, has resigned from the office that 

 he has held for sixteen years and has been suc- 

 ceeded by JVI. Houssay, professor of zoology. 



At the University of Bristol, Dr. Otto Ver- 

 non Dafbishire, lecturer in botany, has been 

 promoted to a professorship; Dr. H. Ronald 

 Hasse has been appointed professor of mathe- 

 matics; Dr. Arthur Mannering Tyndall, pro- 

 fessor of physics; George A. Buckmaster, pro- 

 fessor of physiology, ^nd Major Andrew Eob- 

 ertson, professor of mechanical engineering. 



DISCUSSION AND CORRESPONDENCE 



THE VALENCE OF NITROGEN IN NITROUS 

 OXIDE 



Professor W. A. ISToyes in his address be- 

 fore the American Association for the Ad- 

 vancement of Science in December, 1918,^ 

 spoke very convincingly in favor of the theory 

 of positive and negative valences. The work 

 of Falk, ISTelson and Fry in attempting to 

 apply the conception of electrons to the theory 

 of valence was commended and the theory of 

 G. N. Lewis with regard to non-polar valencies 

 in organic substances was justly criticized. 

 "While pointing out that some of our ideas 

 need revision. Professor ISToyes advocated a 

 new formula for the well-known compomid, 

 nitrous oxide. According to ISToyes, the for- 

 mula should be O ^ E" ^ IST. 



Nitrous oxide, N^O, is usually given the 

 following structural formula: 



1 Science, 44, 175-182, 1919. 



>0. 



According to this formula each nitrogen 

 atom is given a valence of three, but two of 

 the bonds from each nitrogen atom are ar- 

 ranged so that they neutralize one another. 

 The oxygen atom is by common consent given 

 a negative valence of two, so that the polarity 

 (i. e., sum of the positive and negative va- 

 lences) of each nitrogen atom may be re- 

 garded as + 1. According to the conception of 

 positive and negative valences, and in line 

 with Abbegg's assumption that the non-metal- 

 lic elements exhibit maximum positive and 

 negative valences the sum of which is eight, 

 the nitrogen series embraces at least nine 

 stages which, starting with ammonia, in which 

 nitrogen has a negative valence of three, and 

 ending with nitric acid, in which nitrogen has 

 a positive valence of five, runs as follows : 



NHj — NH, . NH, — NH,OH — N, — N.O — 

 NO — NA(HNO:) — NO, — NACHNOj). 



The commonly accepted formula for nitrous 

 oxide, which is to be discarded according to 

 ISToyes, fits very nicely in this series. In Dr. 

 ISToyes's formula, to be sure, he would assume 

 that one nitrogen has a positive valence of five 

 and the other a negative valence of three and, 

 since the algebraic simi of all of the valences 

 on both atoms of nitrogen is + 2, the average 

 polarity of the nitrogen is -f-il as in the old 

 formula. It is obvious that this explanation 

 is a little more complicated than that sug- 

 gested by the old formula. 



Professor Noyes justifies his new formula 

 for nitrous oxide by an ingenious explanation 

 of the way in which this substance is formed 

 from ammonium nitrate. In ammonium ni- 

 trate, Noyes is willing to admit that one 

 nitrogen has a negative polarity of three 

 and the other a positive valence of five. 

 When ammonium nitrate is heated, Noyes as- 

 sumes that the salt is decomposed at first into 

 ammonia and nitric acid, 



NHjNOs ^ NH3 -J- HNO3. 



The ammonia and nitrate acid then tend to 

 form an isomer of ammonium nitrate, 



