Well if you oriental, still believe in ghost and lives under a rock like I do, it's easy to understand. It's like a "ghost" pushing things off your shelf, they don't have a mass but could affect this dimension and they can appear if they have enough energy. The mist has similar characteristics and it's at its peak, that's why it's very visible to the naked eye. What this professor looking for is medium to reach the other dimension which I think technically impossbile -if it possible then in reality we'd be seeing ghost every second. In my opinion, a ghost-communication-box-device thingy is one way to solve such problem, Nikola also tells us to think in term of energy, hence ghost's capability to manipulate electromagnetic. So considering Lelei is a great magician, she might know the answer on how to go to the other dimension in an orthodox way. Just like that one time my preacher lift the barriers on both of my eyes and I start seeing grotesque creatures from another dimension, not a fun ride.
Not a scholar but that is more or less the perspective from my religion and from what I experienced. Can't wait to see the next chap, shit's getting more interesting each page.