The need for an equilibration time for the drug crystals to settle as well as the choice of paramagnetic medium also need to be considered.

Crystals, like other bodies, are either paramagnetic or diamagnetic, i.e. they are either attracted or repelled by the pole of a magnet.

The nitrogen of the air is, as regards the magnetic force, neither paramagnetic nor diamagnetic, whether dense or rare, or at high or low temperatures.