Last week, several aging veterans were watching congressional bailout hearings on TV as lawmakers castigated chief executives of the Detroit Three automakers.
The automotive chieftains were blamed for mismanagement, lack of competitiveness, massive losses, and inability to boost fuel economy in American cars.
"Well, at least, they didn't demand to see the secret 200-mile-per-gallon carburetor that's been hidden for 50 years," I said, facetiously.
General Motors Corp. and Ford Motor Co. bought up those inventions and destroyed the drawings, one veteran assured us.
Big oil companies and the OPEC nations are suppressing dozens of fuel-saving inventions, another of the group told us.
The German army developed hugely efficient carburetors in World War II but managed to explode them before the Allies learned the secrets, one of the old-timers said, with authority.
No, you've got it wrong, another countered: Americans put such superior carburetors in their tanks that they were able to outrun German tanks in Africa in the early days of the war.
The 200-mpg carburetor is one of the most enduring urban legends, and, thanks to the power of the Internet, new versions spring up all the time.
Many of the stories, old and new, involve corporate or government intrigue.
One popular Internet site, snopes.com, has debunked a number of the tall tales, such as a mistakenly released "miraculous car that gets 200 miles to the gallon [that] is reclaimed by the factory and never seen again after its owner calls to congratulate the manufacturers about its miraculous performance."
A similar one in the snopes collection is the couple who drive a new car for thousands of miles on very little gasoline, but find someone tinkering with their car in the driveway, after which their gas mileage is normal.
Other versions: "No-nonsense business types show up to make a fabulous offer for the car, which is accepted," and "the owner wakes up one morning to find the car vanished without a trace."
Many of the stories are traced to an actual event: A Canadian inventor, Charles Nelson Pogue, got four U.S. patents for his "vapor carburetor" in the 1930s and also got a lot of publicity.
For example, one Nevada newspaper's headline proclaimed "Claims Mysterious Carburetor Will Give 400 Miles on a Gallon of Gasoline."
Naturally, no one was allowed to test this magic carburetor, and it was debunked by numerous publications, including Automotive Industries magazine in 1936.
But that didn't stop the legend, which continued to grow - despite some experts saying that anything close to such mileage would require an engine far more efficient than 100 percent, an obvious impossibility.
The miracle-carburetor story resurfaced in a big way five years ago, when a retired English mechanic said he found some of Mr. Pogue's original drawings hidden underneath a sheet of plywood in an old toolbox.
That story, too, got tremendous publicity - at least until one expert who examined the drawings concluded that the carburetor could deliver very good gas mileage "if you're prepared to [take] 10 minutes to accelerate from 0 to 30 mph."
Nowadays, of course, carburetors aren't going to be any help: Cars are fuel-injected.
It's possible, even likely, that the Big Three automakers will vastly improve fuel mileage on cars, maybe even up to the 50 mpg range someday.
But it will be because of smaller, lighter vehicles, more efficient engines, electric-gasoline hybrid technology, and perhaps alternative fuels.
It won't be because of a miracle carburetor kept secret for decades.