Sir James Dewar...inventor of the vacuum flask (or thermos bottle, as it's come to be known.

...and I'll custom-rewrite the old joke so that it fits...

A panel of some of the world's most distinguished scientists are asked to name the one great invention that exhibits the ingenuity of man.

They meet and spend hours tossing around ideas...could it be the computer? The laser? The internal combustion engine? No two of them can agree and the discussion goes on long into the night.

Not knowing that the meeting is still going on the old janitor comes into the room to perform his usual nightly duties. One of the scientists seizes on this opportunity, "Gentlemen, perhaps we have been overthinking the whole thing! Here is a common working man...I suggest that we ask him what the greatest invention in the world is...perhaps his simple mind can find the solution that eludes us."

The janitor isn't quite pleased to be referred to as "simple" but promises to do his best. After some thought, he says, "I guess that the world's greatest invention has got to be the thermos bottle."

The scientists can't believe this answer and the lead panel member asks why the janitor thinks that the thermos bottle is the greatest invention in the world.

"Well," he says, "in the Winter, when it's cold, my wife fills it with hot soup and it keeps the soup hot. And in the summer, when it's hot out, my wife fills it with ice cold lemonade and it keeps that cold."

"So how" asks the scientist, "does that make it the greatest invention in the world?"

The janitor narrows his eyes and whispers conspiratorially, "...how does it know?"

It's an old joke...but Sir James Dewar, a Scot, figgered out how to make it work.


Best

AA