Atmosphere is a deeply subjective thing. What may delight Zippy the Pinhead could depress Bug-Eyed Earl. Or vice versa on a different day. Additionally, Houston tends to celebrate the shiny and new and to destroy the mellow and old, where atmosphere has had time to develop. Thus, the recent opening of The Mercantile, a downtown brewpub and light menu restaurant, represents a near miracle of sorts. The building that houses it was built in 1912 as a silent-picture palace. The theater opened for business four days after the sinking of the Titanic. (Coincidence? We think so. But atmosphere is composed of such moody trifles.) It lasted as the Isis Theater until 1925, when half of the elaborate plasterwork was torn off the walls, a false ceiling put in and a clothing store installed. The retail operation foundered just before World War II, and the building remained untenanted and closed up for half a century. Scott and Lori Littlewood, owners of the recently shuttered Bank Draft brewpub in the Rice Village area, discovered the building and went about removing the false ceiling and restoring the remains of the plasterwork decorations from 1912. The result? Well, terrifically atmospheric.