Page:Graphic methods for presenting facts (1914).djvu/62

 The arrangement of dimension marks with an arrow-head at each end is a convenient scheme worthy of wide use. Note that the percentage figures in the illustration clearly refer to the value of the cotton rather than to the number of bales. The figures representing time, in this case years, read downward as they should do in every case in which horizontal bars are used to represent facts at different periods of time. If the horizontal bars are arranged with the earliest date at the top, any reader who wishes to do so may read the chart as a curve from the left-hand edge of the page and the dates will then appear in correct order from left to right.

World's Work

Fig. 45. The Illustration and the Titles are Shown Above Exactly as Originally Printed

The reader is misled if he does not notice that the earliest year has been shown at the bottom instead of at the top. The wording of the two titles, when taken in conjunction with the chart, really adds to the general confusion

In Fig. 45 the latest date has been placed at the top of the chart. This causes an impression absolutely the reverse of what it was intended to bring out by the drawing. Any one glancing at this chart is likely to suppose that the earlier year is indicated at the top and probably would not notice that the draftsman in this case, for some unjustifiable reason, has reversed the correct arrangement.

Courtesy of "Data," Chicago

Fig. 46. Average Railroad Revenues from Passengers and from Freight in the United States

Here again the earliest year has been shown at the bottom instead of at the top. In tabulations of this sort there is less danger of erroneous reading if the earliest year is shown at the top. Years are usually grouped in fives, including in one group years ending from one to five inclusive, and in the next group years ending from six to ten inclusive

In Fig. 46 also, the latest year has been placed at the top of the column instead of at the bottom of the column. Though some precedent could probably be found for such an arrangement, the arrangement nevertheless seems