P3D Re: DIRDS not SIRDS (how about BIRDS? ;-) )

[jacob@xxxxxxxxxxxxxx (Gabriel Jacob)]

John R writes,
>For the use of the Pulfrich effect for stereo viewing, I have a question:
>did the observation of the effect come first, or did the idea come first,
>followed by development of a way to utilize it?

Here is an interesting excerpt from Zap Science from Klutz, that answers
most of your question.

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Meet Carl Pulfrich

Perhaps the most interesting thing about this illusion is that it was
predicted before it was discovered. Carl Pulfrich, the man for whom it
is named, understood vision so well that he knew this illusion would
exist before anyone had ever stumbled onto it. He ran the whole thing
in his head. Then told his laboratory assistants exactly what to do,
exactly what to expect, and he was exactly right. Pulfrich, incidentally,
never saw the illusion himself. He was BLIND in one eye!
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Gabriel


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