Page:Graphic methods for presenting facts (1914).djvu/297

 mark, all the ink lines can be drawn in rapidly with a draftsman's ruling pen. If the suggested procedure is used, the lines may be drawn so rapidly that there is no chance for the ink to dry on the pen and the ruling operation is almost continuous.

In Fig. 212 we find on a reduced scale the same card that was presented in Fig. 206. Fig. 206 was drawn to full scale in order to show the true size of the figures and the actual spacing. Fig. 212 gives a better idea of the proportion of this card, and though of reduced size, it nevertheless shows the appearance of a card suitable for the plotting of records for one year by weeks, and thus requiring fifty-two entries of figures in the upper part of the card.

In Fig. 212 the arrangement to show the dates along the bottom of the card, with short vertical lines dividing the horizontal scale into months, is not put on to the card until the exact year is known for which the particular card is to be used. Lines dividing the year into months so as to show exactly how many weeks are included in each month and at just which portion of the week the beginning or end of each month may occur are then put in by hand. In Fig. 212 the card has been used for a fiscal year beginning August 1. The card is marked 1911, meaning the fiscal year ending July 31, 1911. By referring to the calendar for the year 1911 one may see how the short lines for months are put in. As the pay weeks ended on Thursday, there were only four pay weeks ending in July, but there were five pay weeks ending in March. March 1 came on Wednesday. The last day of March was on Friday. The vertical co-ordinate lines for March show clearly that there were five Thursdays, and they also show the exact time relation of the Thursdays to the beginning and to the end of the month.

After the month scale for any fiscal year has been marked by hand on one card, any office boy can quickly copy the scale to other cards by superimposing the first card on the next card and copying the pen strokes from the first onto the second card. A supply of cards for any year can thus be made up at small expense, without having to have cards printed differently each year just because mankind has not yet made a calendar which always has the same relation between days of the week and days of the month. The scheme of indicating the relation of weeks and months by the short vertical pen marks permits the carrying on hand of a supply of printed cards which can be used for absolutely any fiscal year without danger of having to send the supply of cards to the scrap basket, as calendars are sent to the scrap basket