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

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Wed, 31 Dec 1997 07:44:56 -0700
>From: jacob@xxxxxxxxxxxxxx (Gabriel Jacob)
>Subject: P3D Re: DIRDS not SIRDS (how about BIRDS? ;-) )

>Meet Carl Pulfrich

>[Quote]
>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!

Thanks for the answer to my question. I think it illustrates that both
reasoning and observation of phenomena are legitimate ways to make new
discoveries. Once the discovery was made, the Pulfrich technique could
be employed fairly inexpensively.

Similar cases:
- Buckminsterfullerene (C60) was proposed before it was manufactured.
  Then it was discovered that it isn't all that rare.
- Helium was discovered on the sun before it was discovered on earth.
- The existence of aluminum was known before it was extracted from its
  compounds. (And for a while, it was more expensive than gold. :-)

P3D and T3D appear to be a hotbed for thought experiments on 3D.
Hopefully some interesting things will eventually appear as a result.

John R


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