It's enough to make you stop complaining about the heat.

Franz Bader, who will be 80 in September, has just opened one of his liveliest shows of the year and has no intention of closing this month, as most dealers do.

And Henri, who just turned 75, has chosen next week to reopen her gallery.

"I think vacations are a bore," says the indomitable Henrietta Ersham, who has a new bronze plaque by the door and new carpeting on the floor at the corner of 21st and P streets (officially 1500 21st St. NW) to announce that her 26-year-old Henri Gallery is back in business.

In fact, Henri never really closed. Two years ago she lost her lease on the building she had occupied in its entirety since Aug. 1, 1967, but since then she has been dealing privately from her top-floor apartment.

Despite the recession, a losing court battle with her landlord to keep her space and the total collapse of her roof during a snowstorm last February, Henri says she can't wait to "make up for lost time" in the newly renovated second floor of the building she says she "still loves," and which--for reasons she still does not know--has suddenly been restored to her.

"I'm in a new period, and I'm thrilled," says the pioneer of the P Street gallery scene.

Several new artists have joined her stable and reflect her quirky, eclectic taste. There are abstract paintings by Frank Herrmann that bow slightly in the direction of neo-expressionism, and witty minimal steel sculptures by Gary Kulak who takes off on the basic form of the chair, making skeletal variations on Shaker and split-back types, all rendered unusable by reason of being too small, too tall or otherwise unsittable.

Peter Charles has made an elegant piece from metal and wood, one of a series based on the image of an urn on a pedestal; June Lathrop's odd wall-hung sculptures made from steel wool conjure mounted elephant tusks and snouts.

From Henri's regular stable, Traute Ishida justifies her dealer's longstanding faith with some of her best work to date--paintings made from pillows, ruffled curtains and other refugees from a white sale, all now fully transformed into paintings of genuine power.

Henri's hours haven't changed. She is open Tuesdays through Saturdays, 11 to 6 and--for those who need art on weekends--from 2 to 6 on Sundays. At Franz Bader

Franz Bader is showing the work of two highly accomplished artists, both new to the gallery. Helmtrud Nystro m from Sweden makes delicate and whimsical color etchings that recall Paul Klee. Washington's own Martha Jackson-Jarvis, a ceramic sculptor, has created two installations that playfully transform the gallery into something of a summer wonderland.

In Jackson-Jarvis' "River Song/Muddy Waters," an array of biomorphic abstract ceramic shapes flutter from the ceiling over piles of sand and glitter, rousing the look and feel of the sea, specifically the tropical sea. Blue striped tiles recall exotic fish; bright orange and green forms hint at tropical birds. Nameless creatures with the texture of sponges or coral crawl the walls, adding mock danger to the scene.

If comparison with Judy Pfaff's underwater environments seems inevitable, Jackson-Jarvis' second installation is unarguably her own. Titled "Game Grids," it consists of 12 stacked grids made from 2-foot-long tubes of extruded red clay, each one sparsely decorated with triangular bits of colored glaze. Within--or upon--each of these log cabin-like structures, Jackson-Jarvis has placed the kind of unspecific primal shapes that are her hallmark: ceramic forms recalling feathers, pods, bones, shells, coral.

As she has set them up, "Game Grids" might be ritualistic games invented by some ancient culture--perhaps native American, or African. But Jackson-Jarvis says that they can also be stacked by their owners as they wish, making them the ultimate executive toy. Each part can be purchased separately, and for extraordinarily modest prices. Prices for Nystro m's exquisitely colored etchings are also remarkably low. Both shows continue through Aug. 20 at 2001 I St. NW, and hours are 10 to 6, Tuesdays through Saturdays.