About twenty minutes

From A treasury of American anecdotes; sly, salty, shaggy stories of heroes and hellions, beguilers and buffoons, spellbinders and scapegoats, gagsters and gossips, from the grassroots and sidewalks of America by Benjamin Albert Botkin. 

Men used to gather in Uncle Jeb’s store on winter evenings to discuss. When their arguments seemed beyond agreement, they referred decision to the aged storekeeper.

Jeb was old, all right. He had been tending the counter now long before most of the men were born. Their most blatant disputation failed to excite him.

Tonight the men were equally divided over the matter of fence posts. Half of the men believed white oak fence posts would last longer than chestnut posts. The other half believed just the opposite.

Finally, the men thought they’d like to settle the matter once for all and consult Uncle Jeb.

“Now, Unc,” says Ben, “what we want to know is, which’ll last the longest, white oak fence posts or chestnut fence posts?”

By and by, Jeb’s rocker came to a standstill. Slowly his pipe came from his lips and he said, “Oak.”

The chestnut men were silent.

At last Will spoke up. “Well, Uncle Jeb, if you say oak lasts longer, how much longer?”

Again everyone was quiet while Uncle Jeb stopped rocking. “About twenty minutes.”