In Fig. 137 the growth in the importance of the loan department can readily be seen by considering the twelve-months progressive moving average showing the average total monthly loans. Though there is, in January, 1912, a very high peak which overshadows all other peaks, the general tendency of the curve is still rapidly upward, because of the fact that a number of high points follow each other in close succession, each nearly as high as the peak of January, 1913, which stands out alone with low points on either side.

The number of separate loan accounts opened and the number of accounts closed is shown in Fig. 137 by means of cumulative curves. The fact that the cumulative curve for the number of accounts closed follows so nearly the angle of the cumulative curve for the number of accounts opened, shows that the number of accounts outstanding has not greatly increased. It also shows that since numerous accounts are being closed, the loans are being made to other employees rather than being repeated continually to the same employees.

Fig. 138 is a study made to determine the size of tank necessary to supply sufficient boiler-feed water for a number of locomotives and tugboats. The average amount of water used each day by all the locomotives combined is given in the lower cumulative curve. The shape of the curve shows that locomotives fill their tanks chiefly between six and nine o'clock in the morning and between five and

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CUMULATIVE CURVES