oils appear in U.S.  Commerce Reports and Philippine Journal of Science.  “The World Wide Search for Oils” in The Americas (National City Bank, N.Y.).  “Modern Margarine Technology” by W. Clayton in Journal Society of Chemical Industry, Dec. 5, 1917; also see Scientific American Supplement, Sept. 21, 1918.  A court decision on the patent rights of hydrogenation is given in Journal of Industrial and Engineering Chemistry for December, 1917.  The standard work on the whole subject is Lewkowitsch’s “Chemical Technology of Oils, Fats and Waxes” (3 vols., Macmillan, 1915).

CHAPTER XII

A full account of the development of the American Warfare Service has been published in the Journal of Industrial and Engineering Chemistry in the monthly issues from January to August, 1919, and an article on the British service in the issue of April, 1918.  See also Crowell’s Report on “America’s Munitions,” published by War Department. Scientific American, March 29, 1919, contains several articles.  A. Russell Bond’s “Inventions of the Great War” (Century) contains chapters on poison gas and explosives.

Lieutenant Colonel S.J.M.  Auld, Chief Gas Officer of Sir Julian Byng’s army and a member of the British Military Mission to the United States, has published a volume on “Gas and Flame in Modern Warfare” (George H. Doran Co.).

CHAPTER XIII

See chapter in Cressy’s “Discoveries and Inventions of Twentieth Century.”  “Oxy-Acetylene Welders,” Bulletin No. 11, Federal Board of Vocational Education, Washington, June, 1918, gives practical directions for welding. Reactions, a quarterly published by Goldschmidt Thermit Company, N.Y., reports latest achievements of aluminothermics.  Provost Smith’s “Chemistry in America” (Appleton) tells of the experiments of Robert Hare and other pioneers.  “Applications of Electrolysis in Chemical Industry” by A.F.  Hall (Longmans).  For recent work on artificial diamonds see Scientific American Supplement, Dec. 8, 1917, and August 24, 1918.  On acetylene see “A Storehouse of Sleeping Energy” by J.M.  Morehead in Scientific American, January 27, 1917.

CHAPTER XIV

Spring’s “Non-Technical Talks on Iron and Steel” (Stokes) is a model of popular science writing, clear, comprehensive and abundantly illustrated.  Tilden’s “Chemical Discovery in the Twentieth Century” must here again be referred to.  The Encyclopedia Britannica is convenient for reference on the various metals mentioned; see the article on “Lighting” for the Welsbach burner.  The annual “Mineral Resources of the United States, Part I,” contains articles on the newer metals by Frank W. Hess; see “Tungsten” in the volume for 1914, also Bulletin No. 652, U.S.  Geological Survey, by same author. Foote-Notes,