On a grassy hill beside their white clapboard church, the good parishioners of St. Mary's Catholic Church in Fairfax stood solemnly yesterday as a white-robed priest sprinkled holy water on the tools of their trades.

Blessed in this symbolic commemoration of Labor Day were, among other things, a Casio pocket calculator, a meat thermometer, a pink feather duster and a bottle of Clorox, a green Dunlop 3 tennis ball, a Spaulding football and a red plastic lacrosse stick.

The "Blessing of the Tools" and annual picnic are Labor Day traditions at St. Mary's, the 123-year-old church where Clara Barton cared for Civil War wounded at the Battle of Manassas. And yesterday, even though there was only one farming tool -- a hoe -- to be blessed (as compared with a half-dozen pocket calculators and at least that many electric typewriters) the feeling of the day evoked some of the parish's past.

It was a happy, comfortable affair where people sat around after the mass, eating fried chicken and swapping stories and smiles. As they did, 45-year church member Teresa Simpson recalled, "in the years when we had the Labor Day picnic before there was even a Labor Day."

The day, said the Rev. Phil Kapela, is designed to be a day to pay homage to "country Catholicism," a remembrance of the old days when Fairfax Station was a place of farmland and rugged men and women who lived off the land. Fairfax Station is a subdivided white-collar suburb today. In those days, Father Kapela said, "people got together for a religious purpose and then spent the rest of the day just having a good time."

The Blessing of the Tools began 12 years ago, Kapela said, a religious purpose that was tailor-made for the social occasion that had been carried out on Labor Day for years. "It is a way of remembering, once a year, the skills and talents that we have and to thank God and ask him to bless the things we produce," he said.

And so parishioners bring some symbol of their work to be blessed. Adults bring calculators or briefcases. The young bring note books or pencils. Or maybe even a soccer ball, depending on where their priorities lie.

Ten-year-old Leigh Wilde, for example, brought her illustrated, full-color copy of "Kurt Thomas on Gymnastics". ForSue Kohler, a decorator, her business card sufficed. Mike Hickey, also 10, had his clarinet blessed "because my mom told me to."

County Board of Supervisors chairman John Herrity, who is really a parishioner of St. Bernadette's, carried forth St. Mary's wooden podium. Several years ago, he said, he brought a copy of the county's budget, hoping for "God's help" on the matter.

And William Bohem, Nancy Runton and Gary Szabo, all of the Fairfax City Volunteer Fire Department, brought their fire engine: big, bright red Old No. 3.

"This fire engine blesses a lot of people around here who need it," said Bohem. "We thought it only proper that it get blessed too."

Pilar Kotwicki, a 16-year-old junior at Robinson Secondary, had her bright orange elementary school crossing safety belt blessed five years ago, but this year she had nothing quite so exotic.

Standing with her friends Mary Swartwood and Kristi Tracy between the dunking booth and the red and white striped hamburger stand, Kotwicki was more interested in other, more important things, she said.

Kotwicki had been on vacation in the south of Spain this summer, Tracy had been at Nags Head and Swartwood had been in Arkansas. "If we didn't come to this picnic and catch up on gossip," Kotwicki said, "we'd never have been ready for school."