[non-math nonsense; delete quick to prevent potential reduction of fun]
=Henry Baker <hbaker1@pipeline.com> Some interesting facts: [...] There's even a scientist who is trying to extract ancient sounds from clay pots that were made on a potter's wheel. His theory is that the sounds modulated the surface of the clay during spinning, so it may be possible to play them back like a record.
Not to detract from the other interesting facts you cite, but I find this very dubious, though it was featured recently in the pop-sci media. Forgive this rant, but I'm finding there's more of this kind of pseudoscience about lately (though more typically in support of sociopolitical agendas). Here, the cited "research" apparently mostly involves manually rubbing a phonograph needle over pots and even painted surfaces and... just listening for... something... that sounds like... something (eg they claimed to just get the word "blue" from some splotch of blue in a large painting)! The potential for delusion in this sort of control-free activity is of course enormous. There are many amusing examples of this (most usually visual), such as that guy who sees clear evidence for tiny fossil unicorns in magnified mineral samples. On closer consideration, you'll find the whole idea is mechanically highly implausible. How did sufficient sound energy get focused in the first place to make the recording clear enough to pick up with a conventional needle (recall those Edison-era phonograph horns?) And since ambient sounds impinge all over the clay, why is the alleged signal spatially localized, instead of "holographically" imprinted? Else what mysterious mechanism somehow causes the potter's massive blunt fleshy finger to act as a precise stylus? And how do these subtle traces persist hanging on the side of a wet glob of mud until, and through, firing? Nah. If it were actually possible to record reliably extractable audio in this way it could be objectively validated by, for example, a simple well-designed double-blind experiment using wholly-mechanized processing to distinguish differently "imprinted" prepared pots. Instead, the advocates leap to seeking permission to scratch up the Mona Lisa in the absurd expectation of somehow "hearing" da Vinci, or his model, or random passersby ("Aren't you done in there yet?" "Klaatu barada nikto!" "Paul is dead."<;-). And why eschew applications? If such effects could be demonstrated at all the potential commercial impact would be significant; look out Napster! Bubble-gum blowing by concert attendees will be forbidden, so as to prevent pirate recordings, etc. Until there's extraordinarily good evidence to support these extraordinary claims, I'm afraid this particular "fact" should be treated (as the Australian Skeptics' site aptly puts it) as "crackpottery".