636 



SCIENCE 



[N. S. Vol. LI. No. 1330 



poured on a tile or an iron plate making a 

 cone. A piece of magnesium tape, about 5 

 centimeters long, has one end thrust into the 

 top of the cone, the other end being bent down 

 so that it is easily lighted by the flame of a 

 match. 



Contrary to expectation there is no violent 

 puff or explosion, as with magnesium powder, 

 but a steady progressive combustion, vivid 

 and brilliant, emitting little smoke. When 

 the whole has burned down there remains the 

 most beautiful mass of crystals of aluminium 

 nitride, Al^lST^, mixed with some crystals of 

 aluminium oxide. 



The greater part of the air which took part 

 in the combustion is thus solidified, only the 

 small amount supporting the combustion of 

 the carbon going off as gases. 



When this nitride is heated with a solution 

 of sodium hydrate ammonia gas is evolved. 



WTien the ammonia is mixed with oxygen 

 or air and passed through heated platinum 

 gauze, nitric acid is produced. 



When the ammonia and nitric acid are 

 made to react on each other the valuable 

 fertilizer ammonium nitrate results. When 

 this ammonium nitrate is mixed with alumi- 

 nium powder a very safe but powerful ex- 

 plosive, "Ammonal" is produced. 



Thus we learn how intimately these chem- 

 ical reactions are related in peace to fertili- 

 zation, and in war to destruction. The ex- 

 periment illustrates: Combustion in which 

 the nitrogen of the air, as well as the oxygen 

 acts as a supporter of combustion; the pro- 

 duction of a crystalline nitride, AlnNj; 

 synthesis of ammonia; synthesis of nitric 

 acid; fixation of nitrogen to serve as fer- 

 tilizer; fiixation of nitrogen to serve as ex- 

 plosive. It would be unwise for us to con- 

 clude that explosives serve only in war. Far 

 from it. Man's best and most serviceable 

 feats in engineering have been made with the 

 aid of these powerful agents. We should not 

 forget how seven acres of rock under Hell 

 Gate were blown to bits by one blast, and 

 ovir harbor opened up to vessels of greater 

 size. 



Charles A. Doremus 



CURRENT RESEARCH AND PUBLICA- 

 TION IN THE AMERICAN MUSEUMi 



In cooperation with the United States Na- 

 tional Museum and other musevims, North 

 America from the Arctic to the Isthmus is 

 now well covered by American Museum 

 activities. Its work includes explorations, 

 publications and photographic collections, 

 relating to historic and prehistoric races of 

 men, to the insects, fishes, amphibians, rep- 

 tiles, birds and mammals, as well as to the ex- 

 tinct ancestors of these living groups. 

 Especially noteworthy serial publications on 

 recent explorations, completed or well ad- 

 vanced, are papers on the " Anthropology of 

 the Southwest " with the Archer M. Himting- 

 ton Fund, the "Bibliography of Fishes" 

 with the Jesup Fund, continued by Professors 

 Dean and Gudger, and six volumes on " Fossil 

 Vertebrates" with the Jesup Fund. Aided 

 by the Jesup Fund, Professor Osborn, as a 

 member of the staff of the United States Geo- 

 logical Survey, has just completed his mono- 

 graph, " Titanotheres of Western America," 

 on which he has been engaged for nineteen 

 and a half years. 



About $75,000 has been expended since 

 1910 on South American exploration and pub- 

 lication through successive expeditions led by 

 Chapman, Eoosevelt, Cherrie, MiUer and 

 Richardson. The senior curator, Dr. J. A. 

 Allen, has produced a series of standard 

 papers on South American mammals. Ex- 

 peditions into the interior bear the name of 

 Theodore Eoosevelt. Dr. Chapman's "Dis- 

 tribution of Bird-Life in Columbia," recently 

 awarded the Daniel Giraud Elliot Medal by 

 the National Academy of Sciences, is a 

 classic and leads to similar volumes on the 

 birds of Ecuador, of Peru and of Chile. 



The Museiun has thus far expended $190,- 

 000 on African exploration, research and 

 publication. Unrivaled collections of reptiles, 

 birds and mammals are in storage awaiting 

 the construction of the African Hall, as the 

 result of the untiring field work of a suc- 



1 Modified from the fifty-first annual report of 

 the president, Henry Fairfield Osborn, May, 1920. 



