The American Society of Mechanical Engineers has invited about fifteen of the chief American societies of national scope to co-operate by sending one member each to a Joint Committee on Standards for Graphic Presentation. Though this committee is not yet completely organized, and it will be some time before any report is available, the reader who desires further information regarding standard practice should be on the lookout for any reports which the joint committee may publish in the future.

This volume may arouse in the minds of many readers a desire for more detailed information than can possibly be given here. The following books are suggested for the person who wishes to take up the study of statistics as related to the collection and interpretation of data without special reference to the methods of graphic presentation. The present work is necessarily limited to the consideration of graphic presentation, and those who wish to go further in the general subject of statistics should by all means consult books of the type exemplified by "The Elements of Statistical Method," by Willford I. King, The Macmillan Company, New York; "An Introduction to the Theory of Statistics," by G. Udny Yule, Grifiin and Company, London; '"Elements of Statistics," by Arthur L. Bowley, Charles Scribner's Sons, New York; "Primer of Statistics," by W. Palin Elderton and Ethel M. Elderton, Adam and Charles Black, London; "Statistical Averages," by Franz Zizek, Henry Holt and Company, New York; "Statistical Methods with Special Reference to Biological Variation," by C. B. Davenport, John Wiley and Sons, New York. Any list of this sort is, of course, incomplete and these books are mentioned as only a few of those which may be found useful to supplement the study of the subject considered in this volume.