Yet already Europe is furrowed by wagons drawn by flame-mouthed dragons. Distances have vanished before the patience of the humble workers of the world, which is reduced to pettiness by the genius of man. The longest journeys have become well-trodden promenades; the most gigantic tasks are accomplished under the potential and tireless hand of this unseen force; a telegraphic despatch flies, in the twinkling of an eye, from one continent to the other; without leaving our armchairs, we converse with the inhabitants of London and Saint Petersburg; yet these miracles pass unnoticed. We do not dream to what struggles, to what mortifications, to what persecutions, these wonders are due; and we do not reflect that the impossible of yesterday has become the actual of to-day. There are men who call to us: "Halt, ye small scientists! We do not understand you! Consequently, you cannot yourselves comprehend what you are talking about!" We may reply: However narrow your judgment, your myopia does not afflict all mankind. It must be declared to you, gentlemen, that in spite of yourselves, despite your ravings, the chariot of human knowledge advances further than ever before, and will continue its triumphal march towards the conquest of new powers. Like the spasms of Galvani's frog, certain crude facts, about which you are skeptical, reveal the existence of natural forces as yet unknown. There is no effect without a cause. The human being is the least known of all beings within our ken. We have learned how to measure the sun, to traverse celestial distances, to analyze starlight; yet we are ignorant as to what we ourselves are. Man is a double being, _homo duplex_; and this double nature remains a mystery to himself. We think; but what is thought? Nobody can say. We walk; but what is this organic action? Nobody knows. My will is an immaterial force; all the faculties of my soul are immaterial; nevertheless, if I will to raise my arm, this volition overcomes matter. How does this power act? What mediation serves for the conveyance of the mental command, in order to produce a physical effect? As yet no one can answer. Tell me how the optic nerve transmits to our mentality a vision of external objects! Tell me how thought conceives and where it resides, and of what nature is cerebral activity! Tell me...! But no! I could question you for ten years, without the greatest among you being able to solve the least of my riddles. In this, as in the cases before adduced, we have the unknown for our problem. I am far from saying that the force brought into play in these phenomena can some day be employed like electricity or steam. Such a notion would be neither more nor less than absurd! Nevertheless, though differing essentially from those, occult force is not the less real.