It was after 11 p.m., and the crowd at the Alexandria City Council chamber had dwindled to a handful when John F. Herrity was called to testify.

Herrity was the 29th of 31 scheduled witnesses at an unusual congressional hearing called by Rep. Herbert E. Harris II (D-Va.) to get his constituents' views on President Carter's proposal to cut impact aid to local school districts.

"I think he (Harris) figured I would leave, but I fooled him," said Herrity, who is chairman of the Fairfax County Board of Supervisors and an announced candidate for the Republican nomination to oppose Harris this fall.

Impact aid pours $19 million a year in federal funds into Northern Virginia school systems, and asking suburbanites if they oppose Carter's plan to take away about $13 million of that is like asking if grass is green.

None of the speakers liked the idea including Herrity, although he said after sitting through the four-hour hearing, "I couldn't detect who we were trying to influence."

That appeared to be a fair comment since the three congressmen who attened the hearing were as much in favor of continuing the aid as were the school superintendents, PTA presidents, teacher union leaders and civic association officers who preceded Herrity to the microphone.

Rep. Dale E. Kildee (D-Mich.), a former teacher, presided in the absence of Rep. Carl D. Perkins (D-Ky.), chairman of the House Subcommittee on Elementary, Secondary and Vocational Education.

Kildee sounded like Howard Baker at the Senate Watergate hearing, repeatedly asking one question of witnesses. Kildee's was this: If the Carter plan is approved, will you have to raise taxes or cut programs? And the witnesses dutifully replied: both.

Rep. Cecil Heftel (D-Hawaii), whose entire state is a single school district that receives heavy does of impact aid, feigned amazement and indignation at the revelations.

"HEW should be exposed to such a hearing," Heftel announced.

Harris, as the host, set the tone for the evening by admitting, "Washington-area suburban school districts have often been pointed to as examples of flaws in the basic program. Some people say that these school districts are wealthy and that impact aid should be targeted to more needy districts."

Then, as if to validate the criticism, the committee heard from two representatives of Fairfax County schools, which by some estimates are in the wealthiest county in the nation.

"We are not as affluent as assumed by many," protested Rodney F. Page, chairman of the Fairfax County School Board. Besides, he added, "We already have high taxes."

Barry Morris, an associate superintendent of the Fairfax system, bitterly recalled the 1974 "reform" of the impact aid program, which made 15,700 Fairfax children ineligible for aid - children whose federally employed parents work outside Virginia, presumably across the river in the District.

The Carter proposal would eliminate another 9,000 of the 26,500 Fairfax pupils, who now are counted in determining federal impact aid package, by making children whose parent work outside the county ineligible.

Heftel suggested that HEW under Carter was "expoiting the willingness of the school districts to compromise."

But Heftel's assessment was too much even for Harris, who said the "HEW position (already) represents a compromise from where they want to be."

Shirley Hines, administrative assistant of Stafford County schools, complained that Stafford County, 40 miles south of Washington, "is hardly a wealthy suburb." But before she could work up sympathy from the audience. Hines testified to a 20-to-1 pupil-staff ratio that must representatives of the wealthier systems wince with envy.

Speaker after speaker testified to the horrors that would follow a reduction in impact aid, but many cited statistics that were based on elimination, instead of reduction, of the program, and other appeared to be comparing apples and oranges.

But this was no hard-hitting congressional investigation, and the soft figures were often followed by even softer questions from the congressmen.

Dr. Thomas L. Penn, chairman of the Arlington County School Board, wondered out loud how much revenue in taxes the county would have if the Pentagon were tract houses and industries instead of a non-taxable federal facility.

Heftel suggested that Arlington school officials might have to tell the government that "you can no longer educate those children (of federal employees) unless we can tax the Pentagon."

In the end, after the camera crews had packed up and all but the most dedicated, had gone, Herrity approached the witness table and read his statement.

"Good evening, Mr. Chairman and members of the committee," he began, managing not to mention Harris by name. Herrity said later he didn't mention Kildee because he had expected to see Perkins. "I didn't know that joker's name," Herrity addmitted.

Herrity didn't complain about his place in the speaking order, although he allowed himself the satisfaction that "I certainly didn't get any preference."

An aide to Harris was asked how the speaking order had been determined.

"By category," he replied. First came the school superintendents and financial officers, then school board members. PTA officers, teacher representatives, civic association leaders, and military base school representatives.

"And then, Herb Harris' political opponents?" the aide was asked.

"The question of politics was farthest from our mind," the aide answered, repressing a grin.

Harris conducted another congressional hearing last Saturday, in Springfield on the subject of Saturday mail delivery.

Herrity didn't bother to sign up for that one.