I have passed unnoticed the great subject of the manufacture of machinery by itself--the invention of the slide-rest, the planing-machine, and many other contrivances by which engines can be constructed with almost mathematical correctness.

I have said nothing adequate about the railway system, or the electric telegraph, nor about the calculus, or lithography, the airpump, or the voltaic battery; the discovery of Uranus or Neptune, and more than a hundred asteroids; the relation of meteoric streams to comets; nothing of the expeditions by land and sea that have been sent forth by various governments for the determination of important astronomical or geographical questions; nothing of the costly and accurate experiments they have caused to be made for the ascertainment of fundamental physical data.

I have been so unjust to our own century that I have made no allusion to some of its greatest scientific triumphs: its grand conceptions in natural history; its discoveries in magnetism and electricity; its invention of the beautiful art of photography; its applications of spectrum analysis; its attempts to bring chemistry under the three laws of Avogadro, of Boyle and Mariotte, and of Charles; its artificial production of organic substances from inorganic material, of which the philosophical consequences are of the utmost importance; its reconstruction of physiology by laying the foundation of that science on chemistry; its improvements and advances in topographical surveying and in the correct representation of the surface of the globe.

I have said nothing about rifled-guns and armored ships, nor of the revolution that has been made in the art of war; nothing of that gift to women, the sewing-machine; nothing of the noble contentions and triumphs of the arts of peace--the industrial exhibitions and world's fairs.
What a catalogue have we here, and yet how imperfect! It gives merely a random glimpse at an ever-increasing intellectual commotion--a mention of things as they casually present themselves to view.

How striking the contrast between this literary, this scientific activity, and the stagnation of the middle ages! The intellectual enlightenment that surrounds this activity has imparted unnumbered blessings to the human race.