Page:Graphic methods for presenting facts (1914).djvu/135

 Frank Haigh Dixon, in the Railway Age Gazette

Fig. 104. Comparative Monthly Earnings and Expenses per Mile of Road of Steam Railroads in the United States Having Annual Operating Revenues of $1,000,000 or More

It is frequently convenient to superimpose curves for successive years, so that seasonal similarities and definite increases or decreases may be accurately studied. Compare this chart with Fig. 103 and also with Fig. 204. It would be better if the heavy line border around the edge of this chart were omitted. The heavy line at the bottom does not coincide with the zero line and the reader may be misled by reading the chart from the border line

different years so that comparisons between these different years are easily made. This scheme of superimposing curves for different years is a very common one that frequently gives an arrangement more convenient than could otherwise be obtained. It will be noticed