Some readers—including my good editor who scoured out my misspellings and grammar errors—stumbled over the notion that Union troops would pour hot water down the exterior slope of the fort’s northwest bastion to make overnight ice to slow if not stop the Rebel attackers.

The so-called Mpemba effect, which actually goes back to observations by Aristotle, is an old story known to soldiers for centuries, but only recently explained by scientists. So Lieutenant Samuel Benjamin, the commander of the defense of Fort Sanders, would have known to heat, if not actually boil, the water before pouring it down the exterior wall. And not been surprised at all when solid ice was the result a few hours later at dawn.