Cards for different years can easily be looked over and the yearly total figures compared instantly, to the great advantage of the executive who has these additions made for him and recorded where they are always in plain sight. Curves as they were used in the past gave the values of single points only, without any summation for a series of points. In Fig. 205 we have not only the yearly total, but also totals for every three months, so that the total for any ciuarter of the fiscal year can be compared with the total for any other quarter.

Fig. 206 represents a four-by-twelve-inch card used to plot data for fifty-two weeks in one fiscal year, the last point of the preceding year being repeated at the left-hand margin. Figures for the repeated week are not given above the co-ordinate ruling, as the repeated figures might then be included in the additions and cause serious error. By repeating the point, however, and not repeating the figures, the curve is made continuous without any danger of adding too many items into the total.

In the right-hand margin of Fig. 206 a vertical green line may be seen. This line may be used as the shank of an arrow to indicate, as

CURVES FOR THE EXECUTIVE

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