Russell McMahon wrote: > The question is not HOW it works from a descriptive point of view or > what happens but how the existence of a particular fraction of a given > gas is "known" about by the same gas on the other side of the > membrane. It doesn't work that way. The mechnism is actually much simpler than that. It's basically about the probability of what each molecule does on its own, then the average effect scaled to the macular level. You're overthinking this. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist