A general correlation for Thomas` scaling law on the flame shapes of natural fires was derived. In addition, the relationships between the heat-absorption rate q<sub>in</sub> and the pool diameter D were analytically represented in form of q<sub>in</sub> = C<sub>1</sub> / D + C<sub>2</sub>[1 – exp(-C<sub>3</sub>D<sup>C<sub>4</sub></sup>)] and the involved adjustable parameters were determined for gasoline, kerosene and diesel oil pool fires. On the basis of the q<sub>in</sub> - D relationships and the general correlation for Thomas` scaling law thus determined, the effective flame temperatures T_e for gasoline and kerosene pool fires were computed. It is found that T_e is varied from about 700 to 900 K and that T_e becomes constant with an increase in D.