FUNCTION PC2H2(T)
C THIS FUNCTION RETURNS THE VAPOR PRESSURE IN BARS.
C BASED ON A LEAST SQUARES FIT TO DATA IN TABLE III
C NBS TECHNICAL PB-151 363
       DATA A,B/21.68901,-2814.018/
       PC2H2=(1./760.)*EXP(A+B/T)
       RETURN
       END