Page:Graphic methods for presenting facts (1914).djvu/90

 The Philadelphia Commercial Museum

Fig. 66. Commerce of the United States since 1830. The Sum of Annual Exports and Imports. Values are given in Millions of Dollars

Such a chart as this is worse than none. There is no scale in either direction. The block for 1830 is drawn with a larger area than the block for 1840 which represents a larger quantity. Compare with Fig. 67 and Fig. 68