io8 TEE POPULAR SCIENCE MONTHLY 



tical nature led them to the execution of great engineering works, their 

 roads, aqueducts and baths still remaining for our admiration to-day. 

 After the fall of the Romans succeeds the long night of the dark ages, 

 learning being kept alive only by the Saracens, and the achievements 

 of the Greeks being so far forgotten as to require to be discovered anew. 

 Finally came the fall of Constantinople with the dispersal in Europe of 

 many Greek scholars, the Eenaissance, and the revival of learning. 

 Conditions were then ripe for the prosecution of all sorts of intellectual 

 pursuits, and we find the study of nature for itself taking on a develop- 

 ment never before dreamed of. To these the church, in many cases, 

 did not offer a welcome. Accustomed, during the middle ages, to the 

 supreme domination over men's minds, she did not look with favor on a 

 movement destined to set them free from all bonds except the truth. 

 Copernicus died too soon to come into conflict with the power of the 

 church, but upon his follower Galileo she wreaked her vengeance, and 

 Giordano Bruno she burned at the stake. Nevertheless, the powerful 

 genius of Galileo gave rise to so many and so important discoveries as 

 to constitute him the father of modern science. Not satisfied with the 

 introspective methods of the Greeks, who often contented themselves 

 with considering how nature ought to work, he developed the modern 

 method of the direct appeal to nature, by means of experiment finding 

 out how she actually did work. When in the presence of the scoffing 

 schoolmen he dropped the heavy and the light weight from the top of 

 the tower of Pisa, and found them both to reach the ground together, he 

 sounded the death-knell of the old and outworn Aristotelian philosophy. 

 It is not my intention here to consider the history of science, and 

 its development from the small beginnings of the cinquecento through 

 its glorious burst in the eighteenth century to full fruition in the 

 nineteenth. Let us briefly recapitulate some of the changes which the 

 works of science have made in the face of the earth, and of mankind 

 inhabiting it. First and most important is the production of power, 

 by which man's energies are inconceivably multiplied. The discov- 

 ery of coal at just the right time to be utilized in the invention of the 

 steam engine enabled man to command hitherto undreamed of forces, 

 making the constructions and manufactures of the ancients seem like 

 child's play. The raising of cotton, made practical by the invention of 

 the cotton gin, largely transformed the clothing of the world, while the 

 development of the iron and steel industry revolutionized methods of 

 construction. With the command of power in centralized units came 

 the development of the industrial system, and the tendency to crowd 

 together into cities, leading to so many scientific problems yet un- 

 solved. With the tremendous increase in the wants of humanity 

 brought about by the increased power to supply them, the supply of 

 natural energy in the form of coal, which at first seemed inexhaustible, 



