20 



The mean international units to which the above equations refer are the 

 averages of units as maintained in the national laboratories of the six countries 

 (France, Germany, Great Britain, Japan, U.S.S.R., and U.S.A.) which took 

 part in this work before the war. The units maintained by the National Bureau 

 of Standards differ from these average units by a few parts in a million, so 

 that the conversion factors for adjusting values of standards in this country 

 will be as follows : 



1 mean international ohm U.S. = 1.000495 absolute ohms 

 1 mean international volt U.S. = 1.000333 absolute volts 



Other electrical units will be changed by amounts shown in Table 5. The 

 factors given should be used in converting values given in international units 

 in National Bureau of Standards certificates to the new absolute system. 



TABLE 5.— RELATIVE MAGNITUDE OF THE OLD INTERNATIONAL 



ELECTRICAL UNITS AND THE NEW 1948 ABSOLUTE 



ELECTRICAL UNITS 



TABLE 6.— RELATIVE VALUES OF THE THREE SYSTEMS OF 

 ELECTRICAL UNITS 



Electromagnetic 



Absolute system 



Quantity Symbol unit emu 



Current strength ... I 1 ampere = 10" 1 abampere = 



Potential difference. . E 1 volt = 10 8 abvolts = 



Resistance R 1 ohm = 10 9 abohms = 



Energy W 1 joule = 10 7 ergs = 



Power P 1 watt = 10 7 ergs/sec = 



Capacitance C 1 farad = 10~ 9 abfarads = 



Inductance L 1 henry = 10 9 abhenries = 



Charge Q 1 coulomb = 10 _1 abcoulomb = 



* Where 3 occurs it is to be taken as 2.99776 (from velocity of light), 

 exponent), it is the square of this number. 



Electrostatic 



system * 



esu 



3 X 10° statampere 



1/300 statvolt 



(1/9) X 10- u statohm 



10' ergs 



10 7 ergs/sec 



9 X 10 u statafarad 



(1/9) X 10- n stata- 



henry 

 3 X 10 9 statcoulomb 



Where 9 occurs (not as an 



SMITHSONIAN PHYSICAL TABLES 



