In MMD 2004.07.16.08 Charles D. Lightfoote asked about the effect of
heat and humidity on pitch as it relates to pipe organ tuning.  Partial
replies were given in MMD 2004.07.17.01-02 and 2004.07.19.06.

Having earlier discussed this to some depth in the MMD Pipes Forum
I ventured to rework my material into a short technical article:
Sound Speed and Pipe Tuning.  It was reviewed by Pipes Forum members
and now appears in revised form at

  http://mmd.foxtail.com/Tech/soundspeed.html and/or
  http://mmd.foxtail.com/Tech/soundspeed2.html [formulae as images]

Johan Liljencrants
Stockholm, Sweden