$10\mathrm{.}63$ A sawn lumber column with a $7\mathrm{.}55\mathrm{.}5-$in$.$ cross section has an

$18-$ft effective length. Knowing that for the grade of wood used the

adjusted allowable stress for compression parallel to the grain is

${}_C=1200$ psi and that the adjusted modulus $E=470{10}^3$ psi,

determine the maximum allowable centric load for the column.