When the thread was formed it extended through the upper part of the tube and lost itself in the lower end.  If it possessed rigidity it resembled, not exactly an elastic cord stretched tight between two supports, but a cord suspended from a height with a small weight attached at the end.  When the finger or a magnet was approached to the upper end of the luminous thread, it could be brought locally out of position by electrostatic or magnetic action; and when the disturbing object was very quickly removed, an analogous result was produced, as though a suspended cord would be displaced and quickly released near the point of suspension.  In doing this the luminous thread was set in vibration, and two very sharply marked nodes, and a third indistinct one, were formed.  The vibration, once set up, continued for fully eight minutes, dying gradually out.  The speed of the vibration often varied perceptibly, and it could be observed that the electrostatic attraction of the glass affected the vibrating thread; but it was clear that the electrostatic action was not the cause of the vibration, for the thread was most generally stationary, and could always be set in vibration by passing the finger quickly near the upper part of the tube.  With a magnet the thread could be split in two and both parts vibrated.  By approaching the hand to the lower coating of the tube, or insulated plate if attached, the vibration was quickened; also, as far as I could see, by raising the potential or frequency.  Thus, either increasing the frequency or passing a stronger discharge of the same frequency corresponded to a tightening of the cord.  I did not obtain any experimental evidence with condenser discharges.  A luminous band excited in a bulb by repeated discharges of a Leyden jar must possess rigidity, and if deformed and suddenly released should vibrate.  But probably the amount of vibrating matter is so small that in spite of the extreme speed the inertia cannot prominently assert itself.  Besides, the observation in such a case is rendered extremely difficult on account of the fundamental vibration.

The demonstration of the fact—­which still needs better experimental confirmation—­that a vibrating gaseous column possesses rigidity, might greatly modify the views of thinkers.  When with low frequencies and insignificant potentials indications of that property may be noted, how must a gaseous medium behave under the influence of enormous electrostatic stresses which may be active in the interstellar space, and which may alternate with inconceivable rapidity?  The existence of such an electrostatic, rhythmically throbbing force—­of a vibrating electrostatic field—­would show a possible way how solids might have formed from the ultra-gaseous uterus, and how transverse and all kinds of vibrations may be transmitted through a gaseous medium filling all space.  Then, ether might be a true fluid, devoid of rigidity, and at rest, it being merely necessary as a connecting