Note: If it is importoni to retain horizontal reodino but sufTicient space lor stondord obbreviolion is not ovoiloble, the initio! letters of the month con sometimes be used: JfMAMJJASOND. This form is not recommended for generol use.

Another oliernolive sometimes used to retain horizontal reading is to indicate months by numerals: I 2 3 4 5 6 7 8 9 10 11 12. This is not oeneroMy recommended becouse many people do not readily associate month numbers with month names.

4. QUARTERS. Designation of quarters can be 1, 2, 3, 4, or 1st, 2nd, 3rd, 4th, with the word "quarter" below, or, if space permits, first quailer, second quarter, etc.

5. YEARS. Where possible, years should be written out in full, whether horizontal or vertical, but if abbreviated, should be shown as -- '28, "29, '30, etc. When abbreviations are used, it is well to have some of the years written out, as follows:

1920 '21 '22 '23 '24 1925 '26 '27 '28 '29 1930

1925*26 "27 •28 '29 1930 "31 Abbreviated yeorly designoilont

STANDARDS FOR TIME SERIES CHARTS

CURVE WEIGHT

Noi*^ Proctlcet rec6mm«nd*d In Ihli tecllon apply primarily to lolld lin* curvai.

Principlet

1. Corves should be sufficiently heavy to attract immediate attention and to impress a visual image on the mind of the reader.

2. In general, time-series curves should be heavier than is the practice in the case of engineering and scientific charts.

Procedures

1. RELATION TO WEIGHT OF RULINGS. Curves should be sufficiently heavy to be distinguished readily from the co-ordinate rulings.