Carbon nanotubes exist in achiral and chiral forms. The chiral nanotubes exist as two enantiomers which are each others' mirror image. By means of symmetry arguments it can be shown that a magnetic field imparts a linear momentum to the chiral nanotube. Inversely, a moving chiral nanotube generates a magnetic field. In order to quantify the first effect, the chiral nanotube is approximated by the quantum mechanical model of a free electron on a helix. (C) 2004 Elsevier B.V. All rights reserved.