"Why should we wait? Why should we run the risk of having our cities destroyed and our lands desolated a second time? Let us go to Mars. We have the means. Let us beard the lion in his den. Let us ourselves turn conquerors and take possession of that detestable planet, and if necessary, destroy it in order to relieve the earth of this perpetual threat which now hangs over us like the sword of Damocles." Chapter II. This enthusiasm would have had but little justification had Mr. Edison done nothing more than invent a machine which could navigate the atmosphere and the regions of interplanetary space. He had, however, and this fact was generally known, although the details had not yet leaked out--invented also machines of war intended to meet the utmost that the Martians could do for either offence or defence in the struggle which was now about to ensue. A Wonderful Instrument. Acting upon the hint which had been conveyed from various investigations in the domain of physics, and concentrating upon the problem all those unmatched powers of intellect which distinguished him, the great inventor had succeeded in producing a little implement which one could carry in his hand, but which was more powerful than any battleship that ever floated. The details of its mechanism could not be easily explained, without the use of tedious technicalities and the employment of terms, diagrams and mathematical statements, all of which would lie outside the scope of this narrative. But the principle of the thing was simple enough. It was upon the great scientific doctrine, which we have since seen so completely and brilliantly developed, of the law of harmonic vibrations, extending from atoms and molecules at one end of the series up to worlds and suns at the other end, that Mr. Edison based his invention. Every kind of substance has its own vibratory rhythm. That of iron differs from that of pine wood. The atoms of gold do not vibrate in the same time or through the same range as those of lead, and so on for all known substances, and all the chemical elements. So, on a larger scale, every massive body has its period of vibration. A great suspension bridge vibrates, under the impulse of forces that are applied to it, in long periods. No company of soldiers ever crosses such a bridge without breaking step. If they tramped together, and were followed by other companies keeping the same time with their feet, after a while the vibrations of the bridge would become so great and destructive that it would fall in pieces. So any structure, if its vibration rate is known, could easily be destroyed by a force applied to it in such a way that it should simply increase the swing of those vibrations up to the point of destruction.