[ Robbie Remarked in 150703 MMDigest:

>[ Player piano vacuum is measured in inches water column; 30 inches
>[ vacuum is pretty loud!  The automotive vacuum gage reads to around
>[ 30 inches of mercury column, so it will barely move when connected
>[ to a player piano.

So that explains why my Duo-Art played so loudly when I set it to 30"
of mercury!  <lol>  Isn't the density ratio roughly times 13?

Eli Shahar

 [ Yes; at room temperature the density of mercury is 13.6 times that
 [ of water.  Lead and steel will float upon mercury!  -- Robbie