Brinton, did practically all the work in preparation of Chapter 46, "The Camera and Its Use"; Chapter 47, "Lantern Slides," and Chapter 49, "Color and Its Use." Miss Audrey W. Zeigler, of Newburgh. New York, made all the drawings used as the headings of chapters. Mr. R. R. Lutz, of the National Industrial Conference Board, made valuable suggestions in the early stages of planning the book, particularly regarding the possibilities for the use of color. Mr. Roy S. McElwee, and numerous others read manuscript and contributed suggestions as the book progressed. In planning the printing, many helpful ideas were given by Mr. Edward N. Mayer, Jr., of Gray Photo Offset Corporation. The cooperation of the entire staff of that organization is appreciated. Personally I regret that frequent absences from the city have prevented that close contact which I should have preferred to give to such fascinating subject matter.

Methods of graphic presentation and new types of charts will continue to evolve through processes of human ingenuity as need arises. There is need for classification and comparison of types noting the advantage of each type and making all types available for general use internationally. Nomenclature alone is deserving of careful attention far beyond the range of any one individual.

In the discussion of these matters in Washington, D. C, during the past year the Honorable Kent E. Keller, member of the House of Representatives from Illinois, and Chairman of the House Committee on the Library of Congress, has been of great assistance in exploring the possibilities. Mr. Keller's unusual range of knowledge and experience in education, medicine, law, engineering, publishing, and mining, coupled with residence in Europe and Mexico, served in determining potentialities for not only a central file of graphic charts by types, but also a comprehensive file of graphic material arranged for quick reference and classified according to subject matter.