The National Park Service, anxious to join the small band of U.S. agencies that turn a profit, is considering sprinkling the tourist-infested area between the Jefferson Memorial and the Smithsonian Institution with 1,114 pay parking meters.

Under the plan being studied by the National Capital Parks central region here, tourists and locals who visit many of the famous memorials by car--including the Washington Monument--would have to pay $2 an hour (in quarters only) for two hours of parking.

Unlike many of the meters run by the District government that are free on Sundays and weekday evenings, the NPS meters would require motorists to pay around the clock, and on holidays, too.

NPS officials, under orders from the White House to cut costs and/or raise revenues, have touched base with the District and learned that owning a parking meter is good business.

The District gets an average of about $600 a year from each of its parking meters, most of which run on six-day schedules and do not require payment after 6:30 p.m. or on Sundays.

Operating on extended hours seven days a week, the NPS figures each meter would make about $840 a year, most of it clear profit.

A top-level NPS memo on the subject of pay parking estimates that the agency would have to pay $289,640 to purchase and install the meters. The annual maintenance cost is put at $66,840 and collection costs are figured at $17,378.

The park service estimates that it would shell out a total of $373,858 the first year the meters were installed and ticking, but would take in $935,760--a most ungovernment-like return on an investment.

The memo from the superintendent of National Capital Parks to the regional director said the District could probably be persuaded to make the collections if it got a percentage of the action.

After the first year of operation, the memo said, "all costs of implementation would be amortized . . . and therefore $561,902 would be profit. For the second and succeeding years, the profit available would jump to $851,542 for each year. These estimates given are, in our view, very conservative."

A NPS spokesman confirmed that the plan is under study, but no final decision has been made.

Meantime, if you have out-of-town visitors coming in this summer tell them to bring, in addition to a sleeping bag, a bag full of quarters -- just in case.