Page:The Fun of It.pdf/85

Rh much on which to base knowledge of one’s position in space. Only the instruments which have been developed in the last few years can be trusted to tell whether one is upside down or right side up. The poor old senses, which serve us so well so often, don’t send the correct impressions to the brain in this instance at all.

Just how far one may be deceived in this way was once clearly shown to me by a certain test. I was blindfolded and put in a chair which could be noiselessly revolved. The examining physician began to turn the chair slowly to the right.

“Which way are you turning?” he asked.

“To the right,” I answered smartly.

“Now which,” he asked a moment later.

“Left,” I answered promptly.

“Lift up the bandage and look.”

I did. I wasn’t turning at all.

“If you had not made the mistake you did, you would not have been normal,” said the doctor cheerfully.

Then he explained that when he first began to turn the chair the direction registered on my brain correctly. If he changed the speed of rotation or stopped, I received the impression I was turning in the opposite direction. Nothing but the sight of objects I recognized or some instrument which could not be fooled could make me believe the direction of the turn was not reversed.

The following is an interesting test which you may experiment for yourself: