[U.S. Government Printing Office Style Manual]
[Chapter 10 - Signs and Symbols]
[From the U.S. Government Printing Office, www.gpo.gov]


10.1.  The increased use of signs and symbols and their importance in 
       technical and scientific work have emphasized the necessity of 
       standardization on a national basis and of the consistent use of 
       the standard forms. 

10.2.  Certain symbols are standardized--number symbols (the digits, 0, 
       1, 2, 3, 4, 5, 6, 7, 8, 9); letter symbols (the letters of the 
       alphabet, a, b, c, d, etc.); and graphic symbols (the 
       mathematical signs +, -,� , x, �). 

10.3.  The signs +, -, �, x, and �, etc., are closed against 
       accompanying figures and symbols. When the x is used to indicate 
       ``crossed with'' (in plant or animal breeding) or magnification, 
       it will be separated from the accompanying words by a space. 

         i-vii+1-288 pages          Early June x Bright (crossed with) 

         The equation A+B                 x 4 (magnification) 

         The result is 4x4            miles � gallons 

         20,000�5,000 


Symbols with figures 

10.4.  In technical publications the degree mark is used in lieu of the 
       word degree following a figure denoting measurement. 

10.5.  Following a figure, the spelled form is preferred. The percent 
       symbol is used in areas where space will not allow the word 
       percent to be used. 

         In that period the price rose 12, 15, and 19 percent. 
         not In that period the price rose 12 percent, 15 percent, 
         and 19 percent. 

10.6.  Any symbol set close up to figures, such as the degree mark, 
       number mark, dollar mark, or cent mark, is used before or after 
       each figure in a group or series. 

         $5 to $8 price range                  but 
         5'-7' long, not 5-7' long             12 (thin space) 
         3 to 5 (no spaces)                    1951 (thin space) 
         �2 to �7; 2��1�                       from 15 to 25 percent 
         #61 to #64                            45 to 65 F not 45 to 
         65 F 


Letter symbols 

10.7.  Letter symbols are set in italic (see rule 10.8) or in roman (see 
       rule 9.56) without periods and are capitalized only if so shown 
       in copy, since the capitalized form may have an entirely 
       different meaning. 

Equations 
10.8.  In mathematical equations, use italic for all letter 
       symbols_capitals, lowercase, small capitals, and superiors and 
       inferiors (exponents and subscripts); use roman for figures, 
       including superiors and inferiors. 

10.9.  If an equation or a mathematical expression needs to be 
       divided, break before +, -, =, etc. However, the equal sign is 
       to clear on the left of other beginning mathematical signs. 

10.10.  A short equation in text should not be broken at the end of a 
        line. Space out the line so that the equation will begin on the 
        next line; or better, center the equation on a line by itself. 

10.11.  An equation too long for one line is set fl ush left, the 
        second half of the equation is set flush right, and the two 
        parts are balanced as nearly as possible. 

10.12.  Two or more equations in a series are aligned on the equal 
        signs and centered on the longest equation in the group. 

10.13.  Connecting words of explanation, such as hence, therefore, and 
        similarly, are set fl ush left either on the same line with the 
        equation or on a separate line. 

10.14.  Parentheses, braces, brackets, integral signs, and summation 
        signs should be of the same height as the mathematical 
        expressions they include. 

10.15.  Inferiors precede superiors if they appear together; but if 
        either inferior or superior is too long, the two are aligned on 
        the left. 

Chemical symbols 
10.16.  The names and symbols listed below are approved by the 
        International Union of Pure and Applied Chemistry. They are set 
        in roman without periods. 

Element           Symbol       Atomic   Element        Symbol    Atomic 
                                  No.                               No.  
Actinium............. Ac           89   Mendelevium......  Md       101  
Aluminum............. Al           13   Mercury..........  Hg        80  
Americium............ Am           95   Molybdenum.......  Mo        42  
Antimony............. Sb           51   Neodymium........  Nd        60  
Argon................ Ar           18   Neon.............  Ne        10  
Arsenic.............. As           33   Neptunium........  Np        93  
Astatine............. At           85   Nickel...........  Ni        28  
Barium............... Ba           56   Niobium..........  Nb        41  
Berkelium............ Bk           97   Nitrogen.........  N          7  
Beryllium............ Be            4   Nobelium.........  No       102  
Bismuth.............. Bi           83   Osmium...........  Os        76  
Bohrium.............. Bh          107   Oxygen...........  O          8  
Boron................ B             5   Palladium........  Pd        46  
Bromine.............. Br           35   Phosphorus.......  P         15  
Cadmium.............. Cd           48   Platinum.........  Pt        78  
Calcium.............. Ca           20   Plutonium........  Pu        94  
Californium.......... Cf           98   Polonium.........  Po        84  
Carbon............... C             6   Potassium........  K         19  
Cerium............... Ce           58   Praseodymium.....  Pr        59  
Cesium............... Cs           55   Promethium.......  Pm        61  
Chlorine............. Cl           17   Protactinium.....  Pa        91  
Chromium............. Cr           24   Radium...........  Ra        88  
Cobalt............... Co           27   Radon............  Rn        86  
Copper............... Cu           29   Rhenium..........  Re        75  
Curium............... Cm           96   Rhodium..........  Rh        45  
Darmstadtium......... Ds          110   Roentgenium......  Rg       111  
Dubnium.............. Db          105   Rubidium.........  Rb        37  
Dysprosium........... Dy           66   Ruthenium........  Ru        44  
Einsteinium.......... Es           99   Rutherfordium....  Rf       104  
Erbium............... Er           68   Samarium.........  Sm        62  
Europium............. Eu           63   Scandium.........  Sc        21  
Fermium.............. Fm          100   Seaborgium.......  Sg       106  
Fluorine............. F             9   Selenium.........  Se        34  
Francium............. Fr           87   Silicon..........  Si        14  
Gadolinium........... Gd           64   Silver...........  Ag        47  
Gallium.............. Ga           31   Sodium...........  Na        11  
Germanium............ Ge           32   Strontium........  Sr        38  
Gold................. Au           79   Sulfur...........  S         16  
Hafnium.............. Hf           72   Tantalum.........  Ta        73  
Hassium.............. Hs          108   Technetium.......  Tc        43  
Helium............... He            2   Tellurium........  Te        52  
Holmium.............. Ho           67   Terbium..........  Tb        65  
Hydrogen............. H             1   Thallium.........  Tl        81  
Indium............... In           49   Thorium..........  Th        90  
Iodine............... I            53   Thulium..........  Tm        69  
Iridium.............. Ir           77   Tin..............  Sn        50  
Iron................. Fe           26   Titanium.........  Ti        22  
Krypton.............. Kr           36   Tungsten.........  W         74  
Lanthanum............ La           57   Uranium..........  U         92  
Lawrencium........... Lr           103  Vanadium.........  V         23  
Lead................. Pb            82  Xenon............  Xe        54  
Lithium.............. Li             3  Ytterbium........  Yb        70  
Lutetium............. Lu            71  Yttrium..........  Y         39  
Magnesium............ Mg            12  Zinc.............  Zn        30  
Manganese............ Mn            25  Zirconium........  Zr        40  
Meitnerium........... Mt           109  

Standardized symbols 
10.17.  Symbols duly standardized by any national scientifi c, 
        professional, or technical group are accepted as preferred 
        forms within the field of the group. The issuing office 
        desiring or requiring the use of such standardized symbols 
        should see that copy is prepared accordingly. 

Signs and symbols 
10.18.  The following list contains some signs and symbols frequently 
        used in printing. The forms and style of many symbols vary with 
        the method of reproduction employed. It is important that 
        editors and writers clearly identify signs and symbols when 
        they appear within a manuscript.

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