"That line's too long, too," I told the cabbie for the fourth time. "Keep circling until you come to a savings and loan with a shorter line."

"That's up to you, Mac," the cabbie said. "But I can tell you I've been all over town this morning, and there aren't any short lines. What the hell's going on anyway? There a run on the banks or something?"

"Surely you know about the new All Savers certificates," I told him. "They've finally gone on sale, and I'm not about to miss out on a good thing."

"Can't say as I blame you," the cabbie said. "If I make enough driving you all over the place looking for short lines, maybe I'll invest a few thou myself," he chuckled. "Seriously, though, I have to tell you, the whole thing makes no sense to me."

"How can it not make sense to earn a couple thousand dollars tax free?" I demanded.

"That's not what I'm talking about," he said. "The part that makes no sense to me is what good it will do for the economy. That's what it's supposed to be about, isn't it? How does it work anyway?"

I explained it to him. The certificates, I told him, are one-year instruments that pay 70 percent of the yield on one-year Treasury bills.

"So why don't I just drive you over to the Treasury Department. That way you can get the full 100 percent instead of only 70. And besides, there's no line at all over there."

I explained that 70 percent was a good deal because I would have to pay taxes on the earnings from a T-bill, while the earnings on an All Savers certificate are tax free, up to $2,000 for a married couple.

"That's enough to offset the 30 percent differential?" he asked incredulously.

"It is if you're earning 30 thou or more a year," I told him.

"I should have known," he said. "This is just another one of those damn loopholes for the rich. The little man pays taxes on every dime he earns, while you fat cats get a free ride. I guess you've already had your expense-account lunch."

I assured him that it takes a lot more than $30,000 a year to qualify as a fat cat and, besides, the All Savers certificates were a good deal for his "little man," too.

"It can't be good for me if I don't have the money to put up, No. 1; and No. 2, you've just explained to me that even if I did, I don't make enough to get in on your rich man's gravy train."

I hate teaching elementary economics, but I did have some time to kill. "Look," I told him. "All that money the people in these lines are investing will then become available for mortgage loans, which means that people like you--the 'little man,' as you say--will be able to buy homes. It works out for everybody."

"There's got to be a catch somewhere," he insisted. "Where did the people in the lines get the money to start with? It seems to me that people are just taking their money out of savings accounts and what you call your money market funds and stuff and then buying these All Savers certificates. How does moving money from one institution to another help me get a mortgage loan?"

I admitted that I had just cashed in some CDs to finance my intended purchase of an All Savers certificate, but I pointed out that S&L industry officials had predicted that a lot of the purchases would be made with "new" money.

"You kidding?" he said. "You mean you rich people have that kind of cash just laying under the mattress?"

"Lying," I corrected.

"I thought you were," he said. "But even if you were telling the truth, what's to guarantee that the people selling these All Savers certificates will lend the money out for mortgages?"

I assured him that the law requires them to do precisely that. At least 75 percent of the money will have to be lent to home buyers.

"They are going to put name tags on your dollars so they can tell them from any other dollars they have? It stands to reason that they are going to lend more money in mortgages than they take in with that All Savers jazz--in fact, they're lending out that much as it is. I don't see where that 75 percent requirement helps at all.

"And one more thing: you say this tax break is good for only one year, right? So you cash in your CDs and invest in All Savers certificates. And then what happens a year from now? You take your money out and put it right back in T-bills, that's what. The S&Ls get your money for a year, and then they turn around and lend it to me for 30 years? You better explain that one to me."

I would have, too, but just then I spotted a line that was only three blocks long. And just as well; he probably wouldn't have understood anyway.