It was like a foot race, Mayor Marion Barry's personal secretary, Patricia Seldon told a visitor. She and Barry both arrived at the District Building at 8:55 a.m. yesterday and tried to beat one another to the executive suite. Barry won.

Thus began a fast-paced day, the fourth of Barry's administration, that included at least seven meetings with staff members and other city officials, puls three out-of-office appointments, one of them ceremonial.

Barry got to work in the black Lincoln limousine with license tag DC1, which picked him up at his modes gray row house at 1236 E st. NE and obeyed all the traffic laws during the 27-block trip.

Now did it feel? "I sort of thought abut the swesomeness of it," said Barry.

Iside the District Building Barry exchanged small talk with building guards, leaned over to pick up a Styrofoam coffee cup someone had carelessly discarded, and warmly greeted Lacy Streeter, a city housing official who served as former mayor Walter E. Washington's general assistant.

The day all went according to schedula -- or, more accurately, as much as 45 minutes behind schedule as the day wore on.

For the first time in memory, reporters were able to keep track of the timetable. Breaking with tradition, the mayorhs press office posted a schedule of Barry's day, a practice it promised to continue.

That was something never done during the 11 years that Walter E. Wahsington occupied the huge fifth-floor office. Sometimes it was difficult to ascertain whether Washington was at work or at home with what staffers often described as a sinus problem.

Barry was much in evidence yesterday. He popped in and out of his office, papers in hand. Like everyone else, he ducked workmen who were noisily knocking down partitions and erecting new ones to provide work spaces for a reorganized staff. Telephone workers crawled beneath desks, installing new multiple-line instruments and assigning new numbers.

The mayor's office itself, almost the only quiet place in the building's east wing, was little changed from the way Washington left it. Only the personal mementos were gone, replaced by dozens of tropical plants moved upstairs from Barry's City Council suite.

Eventually Barry said, the former mayor's ponderous desk and highly polished conference table will be removed. His executive secretary, Dwight Cropp, and his wife, Effi, are contemplating a new decor, Barry said. It will be some kind of "period furniture" he noted, since modern just will not go with the room's somber oak paneling.

Barry also said he plans to reactivate the office's wood burning fireplaces. "The mayor (Washington) told me he wouldn't use it, that this place (the District Building) is a firetrap," Barry said. "Well, I'm going to call the Fire Department and have them come in, and say, 'Light it!'"

After lunch yesterday at the conference table -- a tuna sandwich and a glass of water -- Barry paid his first visit as mayor to a D.C. government office outside the District Building itself. It was the Office of Personnel on the third floor of the city-leased Potomac East Building 613 G St. NW.

He was greeted by George R. Harrod, reappointed by Barry as the city's personnel director. Bofore the September primary, Harrod openly supported Washington for the Democratic nomination that was snatched by Barry.

Yesterday, that was apparently forgotten.Effusive in introuducing Barry to 80 personnel employes, Harrod said the new mayor "is going to turn the government around." In contrasting Barry with Washington, Harrod said, "This is the first mayor I've ever seen in this office here."

Using an organizational chart, Barry briefed the employes on his reshaping of the city government. He said he expects hard work, courtest and involvement from city employes, and long hours from higher ranking officials.

And, Barry said, he will set an example. "The mayor's office is going to be kept open till 8 or 9 o'clock at night," he said. Under the former administration, things would down between 5 and 6.

Suddenly Barry stopped talking, grinned, and stripped off his gray flannel suit jacket. "We get you all together, and it gets rather warm, doesn't it?" he asked. Then he answered a series of questions on such matters as the city's residency requirements for future employes, chile care and upward job mobility.

Leaving the building, Barry encountered Annette Tripiciano, a white-haired city employe who was waiting in the lobby for an elevator.

"When are you going to come see us?" she asked Barry.

"Where are you?" Barry responded.

"Inheritance taxes."

I'll be there," the mayor promised.

On the way to the next appointement, the dedication of the Department of Human Resources' first community group home for retarded adults released from Forest Haven, Barry looked out the limousine window at a red brick row house at 107 Rohode Island Ave. NW.

"That's where I started here in Washington," Barry said, his voice devoid of even a trace of wistfulness.

The house had been local headquarters when Barry was sent her in 1965 to organize the Student Nonviolent Coordinating Committee in the nation's capital.