When Mayor Marion Barry and his advisers met the other day to decide how to bail the District out of its financial crisis, they considered several options, including an increase in the restaurant tax and a news sales tax on gasoline.

They rejected the restaurant tax, saying it would hurt businesses in the District and make it harder for poor people and some middle-class folk to eat out. They chose the gas tax, saying it would raise a lot of money for the city and also encourage people to deep-six their gas guzzlers and use mass transit.

Edward M. Meyers, a city revenue aide who has been advising Barry on tax matters for years, sat in on the deliberations. In no way, Meyers assured a reporter the other day, was the rejection of the restaurant tax linked to the fact that restaurateurs contributed an estimated $40,000 to Barry's 1978 campaign.

Public transportation may be inadequate in some Washington neighborhoods, Meyers conceded. But many poor people don't drive anyway, he said. And it's better to force middle-class people out of their cars and into the subways than to force restaurant customers out of the District.

"The middle class, with the gas price increase, is a group that's ripe to be influenced to use mass transit," Meyers said. "If you discourage the use of the automobile, you get a shift to mass transit. If you discourage restaurant meals in D.C., people will go into Maryland."

That decision makes a lot of cents, especially in the city treasury.

Right not, for example, a three-piece chicken dinner at the Holly Farms store at 3131 Rhode Island Ave. NE costs $2.39 plus 20 cents tax, and a gallon of unleaded sells for $1.26 at Anderson's Exxon down the street. For slightly fancier culinary connoisseurs, the buffet lunch at The Chef's Table, 4414 Benning Rd. NE, is $4.50 plus 36 cents tax and a gallon of unleaded is $1.30 at the Daniels Gulf Station nearby.

If Barry had chosen to increase the restaurant tax from 8 to 10 percent, the chicken dinner would cost four cents more and the buffet nine cents more. Instead, he proposed a 6 percent sales tax on gasoline -- 6 cents more on every dollar's worth purchased. These days, chicken and collard greens at your favorite restaurant usually go a bit further than a gallon of gas.

Money had to be a factor when the decision was made. The gas tax is expected to bring in $13 million a year as compared to $10 million for the restaurant tax. But by Barry's own logic, as outlined in an explanation passed out to reporters, a restaurant tax is nothing to scoff at when it comes to raising funds.

It is a "good steady revenue" source derived from "what is often considered a luxury purchase," the paper reads. Much of the cost actually falls on businesses through employe expense accounts. And many of those actually paying the tax would be suburbanites and tourists. Not to mention -- and the mayor's explanation didn't -- that the building of the downtown convention center is likely to bring more restaurants and restaurant customers to town.

But the District's restaurant tax is already nearly twice as high as that in the suburbs, and why give the city's food service a further burden to bear in their competition with suburban neighbors, the paper agrued. What were the statistics used to substantiate that assertion, Meyers was asked. There were none, he responded. Just "general overall knowledge of the business."

There is at least one statistic to suggest something else. The U.S. Commerce Department reported last year that more consumer dollars go to restaurants and bars in the District than any other retail business. In 1977, sales totaled $379 million at eating and drinking establishments as compared to $355 million at food stores and $204 million at department stores.

Meyers said he was not familiar with such statistics. But in the final analysis the decision to propose the gas tax was made because of its fringe benefit. Not only would it raise money, but it would encourage the use of mass transit as well.

That is a familiar rationale at city hall these days. That's why 13th Street NW is two-way at all times instead of one-way during rush hours. That's why the District government has become a hard-liner on parking violations and expanded its platoons of ticket-writers, towers and booters. That's why the city pushes the federal government to make its employes pay commercial rates for parking.

The city is under real pressure from the Environmental Protection Agency to reduce air pollution, to minimize congestion in neighborhoods and to maximize its revenues in a time of increasing demands and shrinking government dollars.

But the gas tax could produce less than expected. For many, it may simply mean not buying gas in the District and going instead to cheaper stations in the suburbs.

The D.C. Tax Revision Commission recognized that possibility in its report, issued two years ago, when it said, "a higher gasoline tax in the District might not seriously reduce sales."

The Barry administration is not waiting for all the evidence to come in. It has forwarded its proposal to the City Council and said that if the gas tax and other measures are not approved by May 1, up to 5,000 city employes will be laid off.

Meyers knows that if this tax proposal passes, some nighttime joy rides will have to be abandoned. But he predicts harder times for the families who need their cars to get everyone back and forth to work and back and forth to school.

Maybe even the taxi drivers will be back before the Public Serivce Commission soon, asking for another fare increase to cope with rising operating costs.

But any tax is hard. And let's be realistic, Meyers said. "It'll discourage some. But the vast majority of those who drive today will continue to drive. It's not like we're gonna turn everybody into bus riders."

So why not tax the restaurants?