"I'm glad you agree," he said simply. "You see you could not possibly live for a second in electrically produced atmosphere which was so thick that you couldn't hear yourself speak. Death would be instantaneous. It couldn't have been our unknown professor's wireless experiments after all. Yet it seems impossible that a sudden new power should crop up suddenly at one spot like this. Imagine what would happen if this had occurred in a city, in a crowded street. Hundreds would have been stricken blind, then hundreds would have been suffocated. Vehicles would have run amok, and the result would have been an indescribable chaos of the maimed, mangled and distraught. A flash like this green ray (which blinded Miss McLeod and her dog, deluded the General, and nearly suffocated us) at the mouth of a harbour, say, the entrance to a great port--Liverpool, London, or Glasgow--would be responsible for untold loss of life. If this terrible phenomenon spread, Ewart, it would paralyse the industry of the world in twenty-four hours. If it spread still farther the face of the globe would become the playing-fields of Bedlam in a moment. Think of the result of this everywhere! Some suffocated, some blinded, and millions probably mad and sightless, stumbling over the bodies of the dead to cut each other's throats in the frenzy of sudden imbecility." "Don't, Garnesk," I begged. "It won't bear thinking about. We have enough troubles here to deal with without that!" "Yes," my companion admitted, "we need not add to them by any idle conjectures of still more hideous horrors to come. But it is an interesting, if terrible speculation. And it means one thing to us, Ewart, of the very greatest importance. We must solve the riddle somehow." "You mean," I cried, as I realised the tremendous import of his words--"you mean that the sanity of the universe may rest with us! You mean that if we can solve this riddle we, or others, may be able to devise some means of prevention, or at least protection? You mean that we are in duty bound to keep at this night and day until we find out what it is?" "That is just what I do mean," he replied seriously. "It is a solemn duty; who knows, it may be a holy trust. Ewart, we agree to get to the bottom of this? We have agreed once, but are we still prepared to go on with this now that we know we may be crushed in the machinery that controls the solar system and lights the very sun?" "I shall certainly go on," I replied eagerly. "But we can hardly expect you to run risks on our behalf." "It may be in the interests of civilisation," he answered, "and in that case it is our duty. Now look here, Ewart, this will have to be a secret. It is essential that we should not get ourselves laughed at because, for one thing, the scoffers may get into serious trouble if they start investigating our assertions in a spirit of levity. You and I must keep this to ourselves entirely. What about your friend?" "I can trust him," I replied simply.