The Dungeons and Dragons 3.5 rules state:
A character can walk for more than 8 hours in a day by making a forced march. For each hour of marching beyond 8 hours, a Constitution check (DC 10, +2 per extra hour) is required.
Does this mean that the check for the first hour is DC 10, the check for the second hour DC 12, etc? Or does it mean that first hour is DC 12, then DC 14, and so on? (That is, does the first hour count as an "extra hour" for the sake of the +2 to DC?)