Science and Progress 547 



could carry. Later, having domesticated the horse, he learned to 

 ride. By degrees he developed drags to carry his goods, then 

 solid-wheeled carts, and, after centuries, the four-wheeled wagon 

 with spokes and tires. The stage coach lines were his first regular 

 transportation system. 



A marked step forward in transportation was taken when 

 Stevenson, early in the 19th century, adapted the stationary steam 

 engine to transportation and produced a practical locomotive to 

 draw cars on rails. Gradually railroads linked communities to- 

 gether. Locomotives grew in power and better cars and tracks 

 kept pace with their development. Today Science has made possi- 

 ble engines that draw more than a hundred loaded freight cars, 

 and high speed engines which draw passenger trains equipped with 

 all conveniences for day and night travel. Now Science is going 

 a step farther by using electric locomotives which haul trains 

 across plains and over mountain ranges, utilizing the power of 

 distant waterfalls. 



Science triumphed again when, in the closing years of the 

 19th century, the gas engine made possible the development of the 

 automobile. Science has steadily improved the automobile until 

 ' its use has become practically universal in this country, both for 

 business and pleasure. Local and long distance automobile truck 

 and bus lines for freight and passengers are rapidly increasing in 

 number. 



The invention of the gas engine made possible the airplane, 

 man's most rapid means of transportation. In the quarter century 

 since the Wright Brothers developed the first practical flying 

 machine, Science has steadily improved the airplane until we have 

 machines capable of sustained flights of thousands of miles at an 

 average speed of more than 100 miles per hour. During this same 

 period the dirigible balloon has been developed into a practical 

 machine. The airplane and dirigible are bringing about new won- 

 ders in transportation. 



Modern Science has also brought about marked progress in 

 water transportation. From the straddled log and primitive dug- 

 out, man slowly evolved the galley of early Egypt, Greece, and 



