PRINCIPLES OF NAVAL ENGINEERING 



Table 7-3 gives some selected values for 

 mechanical units in British systems of mea- 

 surement. Table 7-4 gives some selected values 

 for mechanical units in metric systems of 

 measurement. Table 7-5 gives some British- 

 metric and metric-British equivalents. The ex- 

 amples given in these tables are chosen pri- 

 marily to help you develop an understanding of 

 the relative sizes of the mechanical units. More 

 complete tables are available in many physics 

 and engineering textbooks and handbooks. 



Bureau of Weights and Measures is in France, 

 Each major country has its own bureauor office 

 charged with the responsibility of maintaining 

 the required measurement standards, including 

 the basic standards of length, mass, and time. 

 In the United States, the National Bureau of 

 Standards (NBS) is responsible for maintaining 

 basic standards and for prescribing precise 

 measuring techniques. 



Length 



STANDARDS OF MEASUREMENT 



The importance of having precise and uniform 

 standards of measurement is recognized by all 

 the major countries of the world, and inter- 

 national conferences on weights and measures 

 are held from time to time. The International 



Until quite recently, the international stand- 

 ard of length was a platinum- iridium alloy bar 

 kept at the International Bureau of Weights and 

 Measures in France. By definition, the stand- 

 ard meter was the distance between two parallel 

 lines marked on this bar, measured at 0°C. 

 Copies of this international standard were main- 

 tained by other countries; the United States 



Table 7-3. —Selected Values of Mechanical Units 

 in British Systems of Measurement. 



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