22 



TABLE 8.— FORMER ELECTRICAL EQUIVALENTS* 



Abbreviations : int., international ; emu, electromagnetic units ; esu, electrostatic units ; 

 cgs, centimeter-gram-second units. 



int. amperes (England, 1906- 

 int. amperes (England, 1909- 



( France, before 



Capacity : 



1 international farad = 

 0.99949 absolute farad 

 1 absolute farad = 

 1.00051 int. farads 

 1 "practical" emu 

 10~' J cgs emu 

 8.98776 X 10 u cgs esu 



Inductance : 



1 international henry = 



1.00051 absolute henries 

 1 absolute henry = 

 0.99949 int. henry 

 1 "practical" emu 

 10 B emu 

 1.11262 X 10- 12 cgs esu 



Energy and power: 



(standard gravity = 980.665 cm/sec" 2 ) - 

 1 international joule = 



1.00041 absolute joules 

 1 absolute joule = 

 0.99959 int. joule 

 10 7 ergs 



0.737560 standard foot-pound 

 0.101972 standard kilogram-meter 

 0.277778 X 10-° kilowatt-hour 



Resistivity : 



1 ohm-cm = 0.393700 ohm-inch 



= 10,000 ohm (meter, mm 2 ) 

 = 12,732.4 ohm (meter, mm) 

 = 393,700 microhm-inch 

 = 1,000,000 microhm-cm 

 = 6,015,290 ohm (mil, foot) 

 1 ohm (meter, gram) = 5710.0 ohm (mile, 

 pound) 



Magnetic quantities : 

 1 int. gilbert = 0.99995 absolute gil- 



bert 

 = 1.00005 int. gilberts 

 = 1.00046 absolute 

 maxwells 

 1 absolute maxwell = 0.99954 int. max- 

 well 

 = 0.7958 ampere-turn 

 = 0.7958 ampere-turn 



per cm 

 = 2.021 ampere-turns 



per inch 

 = 1 line 



= 10~ 8 volt-second 

 1 maxwell per cm 2 = 6.452 maxwells per 

 in. 2 



* This table is now superseded by the adoption of the new system of electrical units in January 1948 

 and is given for reference only. 



Resistance: 

 1 international ohm = 

 1.00051 absolute ohms 



1.0001 int. ohms (France, before 1911) 

 1.00016 Board of Trade units (England, 



1903) 

 1.01358 B. A. units 

 1.00283 "legal ohms" of 1884 

 1.06300 Siemens units 

 1 absolute ohm = 

 0.99949 int. ohms 

 1 "practical" emu 

 10 e cgs emu 

 1.11262 X 10- ,2 cgs esu 



Current : 



1 international ampere = 

 0.99995 absolute ampere 

 1.00084 int. amperes (U. S. before 1911) 

 1.00130 int. amperes (England, before 



1906) 

 1.00106 



08) 

 1.00010 



10) 

 1.00032 int. amperes (Germany, before 



1911) 



1.0002 int. amperes 

 1911) 



1 absolute ampere = 

 1.00005 int. amperes 

 1 "practical" emu 

 0.1 cgs emu 

 2.99776 X 10 9 esu 



Electromotive force : 



1 international volt = 

 1.00046 absolute volts 

 1.00084 int. volts (U. S. before 1911) 

 1.00130 int. volts (England, before 1906) 

 1.00106 int. volts (England, 1906-08) 

 1.00010 int. volts (England, 1909-10) 

 1.00032 int. volts (Germany, before 



1911) 

 1.00032 int. volts (France, before 1911) 



1 absolute volt = 

 0.99954 int. volt 

 1 "practical" emu 

 10 s cgs emu 

 0.00333560 cgs esu 



Quantity of electricity: 

 (Same as current equivalents.) 

 1 international coulomb = 



1/3600 ampere-hour 



1/96494 faraday 



1 absolute gilbert 

 1 int. maxwell 



1 gilbert 



1 gilbert per cm 



1 maxwell 



SMITHSONIAN PHYSICAL TABLES 



