larly as to the skeleton) has likewise been advanced, as previously referred to, in marvelous manner by the application of the "X" or Röntgen rays to the illumination of the human body.
To the great progress in human knowledge must be added the no less gigantic advances in power accomplished by the nineteenth century, and effected by the greater knowledge and mastery of the forces of Nature. Above all must be noticed here the forces acquired by the control of steam, conquering all resistance and giving birth to those noble children of the century—railroads and steamboats. This has brought the powers of legendary giants under the commanding hand of man. A few decades have been sufficient to span the greater part of our globe with space and time annihilating messengers, and by means of the even more marvelous inventions of the telegraph and telephone to bring into direct communication with each other the most distant parts of the earth's surface. Another child of this our century is the phonograph, whose astonishing achievements remind us of fairy tales; and another is the art of photography, which, as already said, has with an unanticipated success been placed in the service of science (astronomy, telescopy, geography, and ethnography). Its instantaeous pictures have brought it about that the successive movements of a complete occurrence are separately reproduced before our wondering eyes as though we saw a repetition of the actual scene. This art, however, still awaits one of its greatest triumphs in the production of colored pictures. We must also mention the invention of dynamite, a product making practicable the exertion of unprecedented energy, and so indispensable wherever great mass effects are to be attained; and also of smokeless powder, which may prove beneficent in abating or even completely abolishing the great continental wars.
Finally, our century has witnessed the union of electric force with chemistry and technics in the form of electro-chemistry and electro-technics, which open the brightest vistas into the future. For the wonderful force of electricity excels in readiness of application and utility all other forces of Nature, and beyond any other vanquishes the checking barriers of space and time. It can, without any special means, be almost directly derived from or changed into all other forms of natural force, and proceeds with an extraordinary velocity through the prescribed paths of the conducting wires. It can, therefore, at any moment be conducted to any place where its effect is required. Dwellings are now illuminated by electricity almost everywhere, and if heating by the same agent and the cooking of food by means of it become common, then is foreshadowed an almost paradisiacal state, in place of the conditions of existence now
