out, to disappear amid the commotions of the following age without leaving a trace behind them. Even after the art of the mechanical multiplication of writings and pictures had made the achievements of mind the common good of mankind; after the foundations of our present science had been laid, and it had been recognized that unchangeable laws lie at the bottom of all natural phenomena, and the only sure way of learning these laws lay in questioning Nature herself, through properly directed experiments—still, scientific and technical progress was toilsome, slow, and insecure. There was still needed a coming out of learning into public life, an infection of empirical art by the spirit of modern science, to release it from the ban of the traditional and mechanical and raise it to the dignity of a scientific art.
We older men among you have had the good fortune to be witnesses of the immense impulse that has been given to human activity, in nearly all departments of life, by the vitalizing breath of natural science. "We have also seen, on the other hand, how science has been advanced by the achievements of art; how art has brought to it a fullness of new phenomena and problems, and with these the stimulation to further investigations; and how, with the spread of scientific knowledge, a host of observers and fellow-workers have grown up to her, in whom, although they may not stand on the full height of scientific knowledge, the love of science has repeatedly made up for that lack.
I will not attempt here to follow up the history of the growth of natural science, and its offspring, scientific art, or to describe the powerful transforming influences which science and art together have exercised upon the spiritual and material development of our period. It has been done many times, in convincing words and a masterly manner.
For us older men it suffices to acquire a view of the great difference between the past and the present—to cast a brief glance back to our own youth. We can still recollect the time when steamboats and locomotives made their first feeble experimental trips; we still hear with credulous astonishment the news that light itself can be made to paint the picture which it renders visible to our eyes; that the mysterious new force, electricity, could transmit news with the velocity of lightning through whole continents and the oceans separating them; that the same force would separate metals, in fixed form, from their solutions; and that it could drive away the night with a light as clear as that of day. Who wonders to-day over these now self-evident things, without which our youth could hardly imagine a civilized life—to-day, in an age when, according to Reuleaux's calculations, several iron laborers work day and night for every civilized man; when millions of men and immense quantities of goods are carried great distances at velocities which were once hardly conceivable; when the world-binding telegraph is not sufficient for the wants of our commerce, and has to make way for the transmission of the living word through the tele-
