CHAPTER XXXII 



HOW MACHINES LIGHTEN LABOR 



Labor-saving devices. - To primitive man belonged the ardu- 

 ous tasks of outdoor life, such as the clearing of paths through 

 the wilderness, the hauling 

 of material, the breaking 

 up of the hard soil of bar- 

 ren fields into soft loam 

 ready to receive the seed, 

 and the harvesting of the 

 ripe grain. 



The more intelligent races 

 among men soon learned to 

 help themselves in these 

 tasks. For example, our 

 ancestors soon learned to pry stones out of the ground (Fig. 

 151) rather than to undertake the almost impossible task of 

 lifting them out of the earth in which they were embedded ; 

 to swing fallen trees away from a path by means of rope at- 

 tached to one end rather than to attempt to remove them sin- 

 gle handed ; to pitch hay rather than to lift it ; to clear a field 

 with a rake rather than with the hands ; to carry heavy loads 

 in wheelbarrows (Fig. 152) rather than on the shoulders; to 

 roll barrels up a plank (Fig. 153) ; and to raise weights by ropes. 

 In every case, whether in the lifting of stones, or the felling of 

 trees, or the transportation of heavy weights, or the digging of 

 the ground, man used his brain in the invention of mechanical 



289 



FIG. 151. Prying a stone out of the ground. 



