James A. Long is actually a personnel man at the Department of Agriculture, but if he were in professional football, he would be "the Turk" -- the bearer of bad tidings, the heavy who notifies players they are being cut.

Long's duty yesterday, on Day No. 2 of President Ronald Reagan's New Beginning, was to carry around the letters from on high, notifying top-level Carter appointees that their resignations were expected by evening.

Similar scenes were being played out throughout the government yesterday as the new administration hit the ground strolling -- not much different, by the way, from other recent changes in administration. In most agencies, the key policy jobs remained unfilled. Carter administration hold-overs in some cases were sitting as acting secretaries, awaiting Senate confirmation of Reagan's choices.

The government kept right on functioning. But as one Pentagon officer said, in wry allusion to the radar-invisible airplane, "We've got a Stealth government over here."

At Agriculture -- Secretary John Block -- already confirmed -- was at his desk early, quickly tied up in meetings. He still had no assistant secretaries to work with. Energy Secretary-designate James Edwards, not yet confirmed, was in his office anyway and among his first visitors were officials of the American Petroleum Institute.

But at other departments, the Carter people were holding forth in caretaker roles. "I'm queen for a day," quipped Robert Herbst, acting secretary of interior, "and it's an honor for me." Albert Bowker became acting secretary of Education after a memo from outgoing Secretary Shirley Hufstedler, naming general counsel Betsy Levin, was countermanded late Monday.

At the State Department, David Newsom, No. 3 man in the Carter hierarchy, played secretary yesterday while the Senate debated the nomination of Alexander M. Haig Jr. for the top job. But big change clearly was about to occur. The first sign: a large pictureboard of department officials, usually on display in the lobby, vanished yesterday.

State's acting spokesman became William Dyess, another Carter hold-over, who gave the briefing yesterday. Dyess introduced himself, then said, "I don't know very much yet. I hope you'll bear with me."

Bear-with-me could become a theme for the coming weeks, as the new administration scurries to match the right people with the right jobs. One of the ways of filling the political jobs will be from the recommendations of the Reagan transition team's personnel crew. Therein lies a vignette.

At the just-vacated M Street offices of the transition team, hundreds of resumes sent in by job-seekers had been stacked in cardboard boxes for shipment to the White House. In the rush to vacate, some resumes had fallen on the floor, presumably fair game for cleaning crews. Among the litter: an imposing 10-page job application from a Maryland man whose job objective, he wrote, was "to assist in the careful implementation . . . of policy."

Economic policy, all by indications, will be of paramount importance to the new administration, but things were bearish on that front. The Council of Economic Advisers was being overseen by Susan Irving, who had been special assistant to Charles Schultze, the Carter appointee who departed the chairmanship. President Reagan still has not named a successor, but White House officials say it will be Murray Weidenbaum.

Carter's deputy Treasury secretary, Robert Carswell, was sitting in as acting secretary, and another holdover, Deputy Assistant Secretary for Tax Policy Emil Sundley, remained on the job by request of the new administration.Tax experts who work under him were busy generating data that persumably will be used for GOP taxcut proposals.

The scene at Treasury mirrored that of other agencies. Old nameplates still adorned the portals, but the faces that went with them were gone. Inside the doors, many vacated offices were unlit.

The Pentagon's prestigious E-ring corridor dramatized the government-wide delays in naming new officials and the vacancies. Outside of Room 3 E 944, which would be the office of Frank A. Carlucci, deputy secretary of defense, the wooden slot for Carlucci's nameplate holds only gobs of sticky glue. Sen. Jesse Helms (R-N.C.) has held up the nomination.

There were at least 10 empty offices in the high reaches of the Justice Department. The top-level Carter appointees who have vacated the rooms have not yet been replaced.

For the interim, the acting attorney general is Charles B. Renfrew, who had been Carter's No. 2 man and who will stay on until William French Smith is confirmed by the Senate and sworn in by Reagan.

The only new people in the attorney general's office were Kenneth Starr and Douglas Marvin, who will hold key advisory roles with Smith. Smith's "confidential assistant," Myra Tankerslee, who had been his law secretary in Los Angeles, dropped by to see her new workplace and stayed long enough to be fingerprinted.

Things were a little bit more mobile at the Department of Transportation, whose acting secretary turned out to be David W. Oberlin, a political appointee on the fifth year of a seven-year tour as administrator of the St. Lawrence Seaway Development Corp., which is not one of DOT's better-known agencies.

None of DOT's operating administrations had new chiefs yet and all of the old ones were gone, including such figures as highway safety administrator Joan Claybrook and federal aviation chief Langhorne Bond.

Who is running the FAA? spokesman Dennis Feldman was asked.

"It's on autopilot," he said.

There was, of course, no doubt that Carter-appointed heads would roll, but there was still widespread confusion over whose and when. Sources at DOT, for instance, reported that Secretary-designate Drew Lewis put out the word that he wants the holdovers out by Friday. The order apparently resulted from a difference of opinion with predecessor Neil Goldschmidt, who thought he had departed with a commitment that his people would be allowed to stay on board for 60 days.

At Education, similar confusion reined. Political appointees got the standard resign-or-be-fired notice, then heard they would be ejected by Monday evening, then were told to show up for work yesterday. Now they're uncertain about which end is up.

No one would dare suggest it will be government business as usual in this new economy-conscious, waste-scorning administration, but the Reagan transition office's litter seemed ominous. Among the items headed for the incinerators were four big looseleaf volumes containing a detailed report on the Office of Management and Budget, and a huge stack of official transition letterhead paper. The frugal would have converted it to notepads.