WHAT A JERK: Ryan Berley, left, at The Franklin Fountain. : Michael T. Regan

Seven inside tables and 12 more on the sidewalk are full, and proprietor Ryan Berley, who lives on the third floor, is watching from his bedroom dressed as just another circa-1910 soda jerk.

In a couple of brisk hours, a 10-person shift will make a few hundred hot fudge sundaes or root beer floats and dish out as many scoops of ice cream in homemade waffle cones. Takeout patrons exit with old-style waxy half-pint, pint or quart cartons. Eat-ins make love to concoctions like a Mt. Vesuvius (a mountain of chocolate or vanilla ice cream erupting with chocolate brownie pieces, cascading with hot fudge and blanketed in malt powder; a dollop of whipped cream indicates her smoking signal) or a vanilla malted milkshake (Berley's favorite).

"You can't go wrong with a classic," Ryan says. "Then again, I have ice cream every day. [Co-proprietor and brother] Eric is the ice cream maker, so he tastes every batch."

Next week, the two will get a taste of the convention of The Ice Screamers, a history-minded international diehard collectors' club that cherishes the old-fashioned ice cream soda parlor and fountain days. The 24th annual event runs June 22 to 24 at the Best Western Eden Resort Inn in Lancaster.

The Berleys are two of the newest and youngest club members in an ever-aging membership. The brothers are also indicative of a trend: More and more members now own or operate vintage ice cream parlors and soda fountains.

"It just completely fits with what we're doing," Ryan says of the club. "Yes, ice cream is the product we're selling, but we've always come at this from the historic perspective."

The convention, which is open to the public from 11 a.m. to 2 p.m. on June 23, is more geared to its 450-plus members, who pay $20 in annual dues. There's a dairy tour, an auction, taste testing (care for some garlic ice cream?) and three educational seminars on Horlick's malted milks, the club's roots and ice cream movie posters.

Northeast Philly's Robert Colella, 67, and his second wife, Arlene Yates, 65, are longtime members. Colella's family owned The Spot Restaurant, a luncheonette with a soda fountain in Bristol, in the 1950s. He just liquidated the old heart-shaped tables and round, red-cushioned counter stools.

Today, his antique scoops are on display in a 5-by-5 oak showcase on a basement wall. Family commitments will keep them from the convention, but not from relishing their membership.

"One year we went exploring [at the convention], and it turned out to be a nice thing," Colella says about first joining. "Years ago, you'd go into every corner store [O'Boyle's was the popular stop in Bristol] and get a milkshake for 20 cents or a quarter—and they'd leave the container with the extra on the counter for you to finish. Today, every milkshake costs over $3, but I still order them."

After the Berleys joined The Ice Screamers in June 2003, the club held a board meeting at the shop when it opened in September 2004. Last year, the brothers spoke about their venture at the convention. This year, they'll socialize and buy, says their mother, Carole. A committed collector and antiques dealer, at one time she decorated the family dining room in an ice cream parlor motif.

The Franklin Fountain, a re-creation of an early 1900s ice cream parlor, is pure period. Its pressed tin walls and ceiling and decorated penny-tile mosaic floor are original to the 1898 building. The menu is based on turn-of-the-century recipes. The banana splits are served in hundred-year-old pressed glass boats.

There's an original counter-top draft tower with silver-plated spigots for soda water and a Tiffany-like lampshade. It's like one that would have first appeared at The Broad Street Pharmacy. Made about 1905, it's been restored and, as far as the Berleys know, is the oldest one in use in the country. The fountain is beneath a reproduction Ben Franklin bust by Jean-Antoine Houdon. (The original in the Philadelphia Museum of Art was the inspiration for the saloon's name.)

The "jerks" occasionally include Robert Berley, their father and a family physician in Delaware. "He's faster than he used to be," Ryan says. "Some nights, he says it's busier in here than it is in the weekend ER."

When it comes to "jerk" lore and protocol, as with everything else, the Berleys rely on history. As the "Dispenser's Formula of 1915" describes: "With dispensers who are live, clean-cut, true men who know their work and do it well and willingly, the service of a fountain is sure to be good." Likewise, the American Soda Book (circa 1900) instructs: "A good soda clerk should be polite, neat of person, and dress, and be able to serve drinks with skill and dexterity."

Then there's the Standard Manual of Soda and Other Beverages (1897): "[The attendant] should have tact, plenty of good nature, and be attentive and obliging. He should be equally pleasant to the child, the old man or woman, and the finely dressed young lady. He should not feel slighted at the "uppishness' of the would-be society young man or the peevishness of the crank. He should never perform any portion of his toilet, such as combing his hair, in front of the apparatus …"

"All timeless wisdom," Ryan says.

Over Memorial Day weekend, the Berleys melted previous sales records. They won't release financial figures, but Ryan, 29, says they served "thousands." Eric, 25, says he's going through 250 gallons of ice cream a week. On the eve of their second summer, business is up 50 percent.

When they began floating the idea, Ryan was working as an antiques trader and consultant to Freeman's auction house; Eric was giving tours at Christ Church, where Franklin is buried. The Berleys admire the namesake's simple, practical business advice and pledge to make the fountain "a democratic place for all."

Before they bought the building, the first-floor store was home to Eroticakes, a purveyor of evocative lollipops and biologically inspired baked goods. Now, the brothers (both bachelors) bring on similar smiles, though purely by inspiring nostalgia.

After a decade in the business of decadence, they hope to launch a national soda fountain museum in Philadelphia. It might also serve as a repository for the collections of The Ice Screamers.

"They don't see many young people as passionate about [ice cream] as we are, so they've embraced us like two adopted sons," Ryan says. "They see us as carrying the torch when they're gone. We'd really like to do that."

The Franklin Fountain is open Sunday to Thursday, noon to 11 p.m., and Friday and Saturday, noon to midnight. Call 215-627-1899 for more information.