Page:Graphic methods for presenting facts (1914).djvu/307

 *tion given on the card in Fig. 216 is much too lengthy to be included as a portion of the title of any curve card. The information on the record card is so specific that a new man in an organization should be able to follow the card instructions and assemble all the data necessary to plot each curve in the whole set.

Information cards such as are shown in Fig. 216 can sometimes be simplified by expressing the information as a formula. Curve numbers used in a formula may greatly simplify the method of expressing the fact that several sets of data must be added and one total divided into another total to obtain a desired ratio. Though information cards like that depicted in Fig. 216 are used principally by the man who plots the curves, they are filed in such convenient location that they may be referred to by any executive who wishes to know the source of the data plotted on any curve card, or who wishes to see just what figures are included and what are excluded in making up any grand totals. The use of the serial numbered information card gives full information in condensed and easily accessible form.