What is "bolting cloth"

Bolting \Bolt"ing\, n.

1. A sifting, as of flour or meal.

2. (Law) A private arguing of cases for practice by students, as in the Inns of Court. [Obs.]

   Bolting cloth, wire, hair, silk, or other sieve cloth of different degrees of fineness; -- used by millers for sifting flour.
   --McElrath.

   Bolting hutch, a bin or tub for the bolted flour or meal; (fig.) a receptacle.