^^^ '^'^'^^'^• ■ ^'^"^^'f"^ '' P^ hand corner of the

Fig. 2 1 6. Each Curve Card Plotted Periodically Has a Serial Number. A 4-incli by 6-uicli Record Card is Filed by the Curve Serial Number to Give the Complete Information Necessary so that Anyone May Know How to Collect the Data and Plot the Curve. The Card, Shown Above, Refers to Curve 2678 Shown for Three Years in Fig. 207 and in Fig. 208

card, as in Fig. 215, to identify the card and show that it represents all the data for the halfdecade ending in that year.

It is not feasible or desirable to place on each curve card a title so complete that it gives all the information concerning the source of the data used in plotting the curve. It is better to use a fairly short title, and then have all supplementary information given on a separate card to which reference, if necessary, can easily be made. Fig. 216 shows a 4-by-6-inch card such as is used in conjunction with each curve card regularly plotted. The number on this card corresponds with the serial number on the curve card as will be seen by referring to Fig. 205 and Fig. 207. If two or more curves appear on the curve card, a card like that in Fig. 216 would have subheadings such as 2678A, 2678B, etc., all shown on the same card No. 2678. It will be seen that the informa-

CURVES FOR THE EXECUTIVE 287