DEVELOPMENT OF HIGHWAY TRAVEL MITMAN 327 



as human carriers, but the horse continued to be, because of his 

 fleetness of foot, man's favorite personal carrier. 



II 



In 1914 Berth old Laufer ^ wrote: 



Whatever our modern progress in the perfection of land transportation may 

 be, whether we consider our steam-engine or motor cars, they all depend upon 

 the basic principle of the wheel — that wonderful invention of prehistoric days, 

 of the time, place, and author of which we are ignorant. 



Archeological researches have yielded no evidence as to the in- 

 ventor of the wheel, and it is unlikely that any evidence will ever be 

 found because of the great antiquity of the invention. Egypt had 

 neither the horse nor the wagon until they were introduced by in- 

 vaders from the East about 3500 B. C. Europe knew nothing of the 

 wheel, the plow, or domesticated animals until well in the Bronze 

 Age, approximately 1500 B. C, and it was about this same time that 

 China first heard of them. It is quite reasonable to assume, there- 

 fore, that the wheel and cart were devised in Asia, possibly about the 

 time, 8000 B. C. to 6000 B. C, that man first taught the horse to 

 drag his plow for him. 



There are two schools of thought regarding man's discovery of 

 the wheel. Both schools are agreed that he first devised the sled 

 to transport objects and food too heavy for him to carry on his own 

 back. Both assume too that he knew at a very early period how to 

 convert sliding friction into rolling friction by placing round logs 

 under his sled to facilitate its movement and that this suggested the 

 wheel. From this point on the two schools differ. The older and 

 larger one thinks along evolutionary lines and believes that by slow 

 degrees the roller under the sled became a revolving axle with thin 

 sections of larger logs or disks attached to its ends. Then followed 

 the discovery that when a hole was made through the center of the 

 disk so that it could revolve freely on the axle instead of the axle 

 turning, the rudimentary form of the wheel of today was evolved. 

 To reduce the weight of the solid disks man subsequently successfully 

 tried thinner disks reinforced with crossbraces, and by the gradual 

 elimination of excess wood and the addition of more crossbraces, the 

 wheel composed of felloes and spokes resulted. 



The second and newer school does not believe in the evolutionary 

 development of the wheel but does believe that as soon as the value 

 of the roller became known some individual proceeded directly to 

 perfect a wheel by forming a circle of twisted reeds or grasses, which 

 was kept in shape by crossbraces and prevented the wheel from col- 



1 Laufer, Berthold, Some fundamental ideas of Chinese culture. Journ. Race Deyelop- 

 ment, vol. 5, no. 2, October 1914. 



