If charts similar to Fig. 124 are used, the executive can tell instantly whether the stocks in different departments or of different kinds of material are increasing or decreasing simultaneously and proportionately.

"To summarize -- with the ordinary arithmetical scale, fluctuations in large factors are very noticeable, while relatively greater fluctuations in smaller factors are barely apparent. The logarithmic scale permits the graphic representation of changes in every quantity without respect to the magnitude of the quantity itself. At the same time, the logarithmic scale shows the actual value by reference to the numbers in the vertical scale. By indicating both absolute and relative values and changes, the logarithmic scale combines the advantages of both the natural and the percentage scale without the disadvantages of either."

Chapter VIII

COMPONENT PARTS SHOWN BY CURVES

: 4Hfi C*KDLC-PO«CR Q

TMC DirrtHENT TY("Ca C

8TAM)AAD IMCftNOCSCEHT LAMPS

« CO. AB PC»»CCWT»OEB or TMt JOTALB or ALL LAMPS QELIVCBED

S cahsoh I ocw

QTfcWTALOM Jg TUNOBTtH

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. x\ll 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.