We didn't quite manage 4:30, but shortly after 5 PM the remains had reached the point where we decided we could call it a day. I spread the ashes out as finely as I could and Lisa set the sprinkler on them. We left the sprinkler running for an hour or so, then came out, stirred the ashes several times, and drowned them thoroughly. (I didn't spend a fair number of years living on US Forest Service bases for nothing.) What started the day as a pile of wood and brush is now a small pile of goopy black ashes.
When we went inside and I went to wash up, I discovered that I must have been getting too close to the fire, as the area above my glasses and below the rim of my hat is all red, like a sunburn. Darn annoying, that.
Unfortunately, the neighbor's burn continues, so the whole town is blanketed with his smoke. It's so bad that I started coughing just walking the 300 m across the property, and it makes going out for a walk after dinner a very unpleasant proposition.