Old Temperature Controller

I happened to bid Yahoo auction, hi-temp therm controller by chance at 2,000 yen the other day. The purpose is making use of it for US made Muffle NEY Burnout Oven with no controlling of thermometer and mooring program, probably the controller card might be broken. It looked fully mechanical controller as it did, imagined I that I could control NEY Muffle by just connecting it and also it's mechanical construction might be relatively easily understood how to do that. My own shallow and frivolous thought brought troublesome at all. First of it is huge body than expected, too big sized it is!
Second, it disappointed me so much when the service door in the front is opened, 3 pieces of glass tube containing Mercury were observed, how come, what are they for? Remembering the very specific switching system invited for the Automatic Air Force Flap in Japanese fighter while the WW2, US Code name George.
The glass cylindrical switches with mercury moving terminals are controlled by some cum construction moved by the servo motor, mechanically so complicated.
Though the construction inside is so polite and refined, it's hidden potentials are above my understanding, in spite of  tens years of manufacturing, the company is still now operating condition, am I going to ask them to share any information about this ancient temperature controller?