What is "to bank up a fire"

Bank \Bank\, v. t. [imp. & p. p. Banked(b[a^][ng]kt); p. pr. & vb. n. Banking.]

1. To raise a mound or dike about; to inclose, defend, or fortify with a bank; to embank. ``Banked well with earth.''
   --Holland.

2. To heap or pile up; as, to bank sand.

3. To pass by the banks of. [Obs.]
   --Shak.

4. (Engineering) To build (a roadway or railroad) with an inclination at a curve in the road, so as to counteract centrifugal forces acting on vehicles moving rapiudly around the curve, thus reducing the danger of vehicles overturning at a curve; as, the raceway was steeply banked at the curves.

   To bank a fire, To bank up a fire, to cover the coals or embers with ashes or cinders, thus keeping the fire low but alive.