[ Ref. Rowland Lee in 150818 MMDigest
 [ http://www.mmdigest.com/Archives/Digests/201508/2015.08.18.02.html 

If you count the magnet valves on the main section of the chest, there
_are_ 58 of them.  There are two other magnet valves located on the
side section that operate large valves.  One could guess that they are
stop controls, one for each of the two rows of 58 reeds (?) visible in
the photos.

Larry Kerecman