This description of Tesla's "magnifying transmitter", which supposedly used electrical resonance to transmit energy (similar to resonant inductive coupling?) states that the coils (or at least part of them) are submerged in liquid air, which "causes an extraordinary magnification of oscillation in the resonating circuits".
What effect would submerging a coil in liquid air actually have? Does it just decrease resistance of the coils? I know with resonant inductive coupling, efficiency is improved with higher Q factor of the RLC circuit, and Q is improved by reducing the resistive component, so would this make some sense?
Does it have any other effects? Electrical conductivity, magnetic permeability, etc?