He could, however, see very clearly that his own position in the sales force was getting better or worse, according to whether his relative-rank line pointed upward or downward. This comparison of selling units on a rank basis is in many respects fairer than any curve based on the value of sales. Good business conditions or bad business conditions afi^ecting all alike do not show up in charts like Fig. 63. What is shown is the real progress or lack of progress made by every man or branch selling house as compared with all the others.

Printer's copy for a chart like Fig. 63 can very easily be made up if printed strips of the blocks shown in the chart are used. These, if desired, could be made from Fig. 63 itself. Simply photograph the chart, then take one vertical row of the blocks, as for the year 1900, and have a line engraving made of them, eliminating the figures

64 GRAPHIC METHODS

for numbers which appear in the middle of each block. Print from the zinc plate a number of strips of blocks. With shears and a pastepot, another vertical row of blocks may be added at the right-hand edge of the chart copy each month to provide "copy" for the plate to print the succeeding month's illustration. The identification could be lettered by hand inside of the vertical row of blocks for the latest month. It then takes only a short time to draw lines joining blocks having corresponding numbers. The built-up "copy" is then ready for the engraver to make a zinc plate. Zinc plates cost so little that there is almost negligible expense required for the new line cut needed each month.