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 given space by dividing into tenths and hundredths and using tables of logarithms.

It is of interest to note here that the data of Fig. 121 would show as a perfectly straight line if plotted on paper having the logarithmic ruling for the vertical scale. Since the increase from year to year is uniform, on a percentage basis, the points of the curve all fall on a straight line drawn from the first point to the last point.

W. J. Cunningham in Proceedings of New England Railroad Club

Fig. 124. Book Value of Material on Hand for a Large Eastern Railroad

The logarithmic scale is particularly valuable for an operating chart such as this when there is a great difference in the size of the figures which must be compared. The lower curve here averages about $60,000 while the upper curve averages about $1,100,000. The logarithmic scale permits accurate comparison of various curves to determine whether any curves are out of harmony with the other curves

Fig. 124 gives an especially interesting use of curves on the logarithmic ruling. Executives who have puzzled over methods for controlling the quantity of materials or supplies on hand realize full well that it is sometimes just as important to watch the curves for materials having only a relatively small consumption as it is to watch the curves for those materials of which the greatest quantity is used. The mere fact that great amounts of capital are tied up in stocks of certain largely used materials tends in itself to cause very careful scrutiny of those accounts, while numerous small or inactive accounts may be entirely overlooked or neglected. A little study often shows that there is no necessity for carrying so much material on hand.