Page:Graphic methods for presenting facts (1914).djvu/158



COMPONENT PARTS SHOWN BY CURVES

In Chapter I various examples were given in which the component parts or factors making up a complex whole were shown in their relative sizes. It frequently happens that it is necessary to show the changes which occur in the size of different components as time goes on. In this chapter we shall consider only examples of charts showing the fluctuating size, at different times, of components which make up a total of 100 per cent.

In Fig. 125 the proportionate number, voltage, and candle-power of various types of standard incandescent lamps delivered in different years by the New York Edison Co. are shown in a series of vertical bars which are all of the same length, representing 100 per cent. No statement is made or implied in regard to the total figures, which may have increased or decreased from year to year. All we are interested in, in this chart, is the proportion of the different components which in their aggregate make up the bar representing 100 per cent in any year.

New York Edison Company

Fig. 125. The Number, Voltage, and Candle-Power of the Different Types of Standard Incandescent Lamps Delivered by the New York Edison Company in Different Years, Shown as a Percentage of the Totals of All Lamps Delivered

The chart was drawn in four contrasting colors and was framed for a wall exhibit

In Fig. 126 the total height of the chart represents 100 per cent.