The general arrangement of a chart should proceed from left to right.

3. Figures for the horizontal scale should always be placed at the bottom of a chart. If needed, a scale may be placed at the top also.

4. Figures for the vertical scale should always be placed at the left of a chart. If needed, a scale may be placed at the right also.

5. Whenever possible, include in the chart the numerical data from which the chart was made.

362 GRAPHIC METHODS

6. If numerical data cannot be included in the chart, it is well to show the numerical data in tabular form accompanying the chart.

7. All lettering and all figures on a chart should be placed so as to be read from the base or from the right-hand edge of the chart.

8. A column of figures relating to dates should be arranged with the earliest date at the top.

9. Separate columns of figures, with each column relating to a different date, should be arranged to show the column for the earliest date at the left.

10. When charts are colored, the color green should be used to indicate features which are desirable or which are commended, and red for features which are undesirable or criticized adversely.

11. For most charts, and for all curves, the independent variable should be shown in the horizontal direction.

12. As a general rule, the horizontal scale for curves should read from left to right and the vertical scale from bottom to top.