Most any oil based varnish takes a long time to really harden up...as you're finding out. Very slow evaporation of solvents is part of what makes it easy to handle. You can add a little japan dryer to speed things up some, but it's the nature of the beast. The good is that once it does set hard it's a good(and good looking) finish. Another thing I've done is to modify their recommended application procedure. Thin a little (maybe 15 0r 20%) with mineral spirits, and use more like a wiping finish. The table I showed earlier was finished this way. It's the kind of thing you just can't rush, which is why industry has mostly gone to hotter solvent based and catalyzed finishes.
Counter intuitively, the fan may have slowed things down some. Force drying will tend to dry just the surface and create a sort of skin that traps the solvents in the underlying layers, thus slowing down the evaporation.
Time will be your friend.
