494 POPULAR SCIENCE MONTHLY. 



larly as to tlie skeleton) has likewise been advanced, as previously 

 referred to, in marvelous manner by the application of the " X " or 

 Rontgen 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 ]STature. Above all must be noticed here the forces ac- 

 quired by the control of steam, conquering all resistance and giving 

 birth to those noble children of the century — railroads and steam- 

 boats. 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. An- 

 other child of this our century is the phonograph, whose astonish- 

 ing achievements remind us of fairy tales; and another is the art of 

 photography, which, as already said, has with an unanticipated suc- 

 cess 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 occur- 

 rence 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 at- 

 tained ; and also of smokeless powder, which may prove benef- 

 icent in abating or even completely abolishing the great conti- 

 nental 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 applica- 

 tion 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 extraordi- 

 nary 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 cook- 

 ing of food by means of it become common, then is foreshadowed an 

 almost paradisiacal state, in place of the conditions of existence now 



