As time passed and manufacturing methods were im- 

 proved, the automobile proved more and more reliable. 

 Service facilities were more frequently to be found, and the 

 brawny hand of the blacksmith was laid less often on the 

 machine in need of repairs. Garages with mechanics and 

 replacement parts appeared, and women took up the art of 

 driving as the risk of breakdowns became less. 



Interchangeability of parts, upon which ease of replace- 

 ment and assembly-line manufacture both depend, was 

 dramatically demonstrated when the Royal Automobile 

 Club of Great Britain in 1908 presented the Sir Thomas 

 Dewar trophy to Cadillac for the most meritorious per- 

 formance in any trial held by the Club during the year. 

 The trial consisted of completely disassembling three new 

 1 -cylinder Cadillac automobiles, mixing all the parts, and 

 reassembling the vehicles from parts picked at random. 

 After the assembly the engines were started easily, and test 

 runs of 500 miles were made. 



This trial showed that the manufacture of parts to toler- 

 ances permitting assembling without slow, skilled hand fit- 

 ting was a workable American practice. Assembly-line 

 manufacture based on this practice has made possible the 

 high production records of the automobile industry in 

 peace and war since 1908. 



Since November 28, 1895, the date of America's first 

 automobile race, many speed contests and reliability trials 

 have been held in this country, and both types of events 

 have had a telling effect on the automobile. These con- 

 tests, in which machines vied with one another, led the 

 manufacturers and engineers to develop increasingly better 

 tires, alloys, lubricants, and other components of the auto- 

 mobile, resulting in the long-lived and serviceable vehicle 

 we know today. 



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