-> And looking back at that issue,  I eventually found a magnet  
-> enthusiast who stated that the device's upper limit comes when a  
-> ball finally slams into the next magnet at a speed sufficient to  
-> shatter it's fragility - they're a bit like glass, apparently... 
  
Ceramic magnets are, yes. 
  
On the other hand, a friend of mine was once assembling a big 
electromagnet. He neglected to tighten the bolts sufficiently, so when 
he turned the thing on, one pole-piece crashed into the other. He 
couldn't separate them by force, so he reversed the windings so the 
pole-pieces repelled each other. When he energized the coils, one 
pole-piece broke free, flew across the room, and smashed through the 
wall into the next room. He retrieved it from there, undamaged. 
  
                                 dow 
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