Sporting the costume of a Civil War-era reporter in Manassas. (Courtesy Timothy R. Smith)

I’ve always found hats to be too hot in the summer. But though this one is black and thick, it has a curve along the hairline that allows air to enter and circulate, keeping the top of my head cool.

And as a result, the rest of my body feels cooler.

These Civil War sartorialists must have been on to something.

The Post’s Timothy R. Smith will be blogging all day from the events in Manassas honoring the 150th anniversary of the Battle of Bull Run.