What is "to double upon"

Double \Dou"ble\, v. i.

1. To be increased to twice the sum, number, quantity, length, or value; to increase or grow to twice as much.

   'T is observed in particular nations, that within the space of three hundred years, notwithstanding all casualties, the number of men doubles.
   --T. Burnet.

2. To return upon one's track; to turn and go back over the same ground, or in an opposite direction.

   Doubling and turning like a hunted hare.
   --Dryden.

   Doubling and doubling with laborious walk.
   --Wordsworth.

3. To play tricks; to use sleights; to play false.

   What penalty and danger you accrue, If you be found to double.
   --J. Webster.

4. (Print.) To set up a word or words a second time by mistake; to make a doublet.

   To double upon (Mil.), to inclose between two fires.