800

INVENTIONS OF NIKOLA TESLA.

forcibly expresses it in the description of his admirable experi-ments, in which liquid oxygen is handled as one handles water,and air at ordinary pressure is made to condense and even tosolidify by the intense cold. Experiments, which serve to illus-trate, in his language, the last feeble manifestations of life, thelast quiverings of matter about to die. But human eyes shallnot witness such death. There is no death of matter, forthroughout the infinite universe, all has to move, to vibrate, thatis, to live.

I have made the preceding statements at the peril of treadingupon metaphysical ground, in my desire to introduce the subjectof this lecture in a manner not altogether uninteresting, I mayhope, to an audience such as I have the honor to address. Butnow, then, returning to the subject, this divine organ of sight,this indispensable instrument for thought and all intellectual en-joyment, which lays open to us the marvels of this universe,through which we have acquired what knowledge we possess, andwhich prompts us to, and controls, all our physical and mentalactivity. By what is it affected ? By light! What is light ?

We have witnessed the great strides which have been made inall departments of science in recent years. So great have beenthe advances that we cannot refrain from asking ourselves, Isthis all true, or is it but a dream? Centuries ago men havelived, have thought, discovered, invented, and have believed thatthey were soaring, while they were merely proceeding at a snail’space. So we too may be mistaken. But taking the truth of theobserved events as one of the implied facts of science, we mustrejoice in the immense progress already made and still more in tjieanticipation of what must come, judging from the possibilitiesopened up by modern research. There is, however, an advancewhich we have been witnessing, which must be particularlygratifying to every lover of progress. It is not a discovery, oran invention, or an achievement in any particular direction. Itis an advance in all directions of scientific thought and experi-ment. I mean the generalization of the natural forces and phe-nomena, the looming up of a certain broad idea on the scientifichorizon. It is this idea which has, however, long ago taken pos-session of the most advanced minds, to which I desire to call yourattention, and which I intend to illustrate in a general way, inthese experiments, as the first step in answering the question“What is light?” and to realize the modern meaning of thisword.