ON STANDARDS FOB USB IN ELECTRICAL MEASUREMENTS. 43 



(8) L'intensite efficace est la racine carree du carre moyen de I'in- 

 tensite du courant. / 



(9) La force electromotrice efficace est la racine carree da carree moyen 

 de la force electromotrice. 



(10) La resistance apparente estlefacteur par lequel il faut multiplier 

 l'intensite efficace pour avoir la force electromotrice efficace. 



(11) Dans un accumulateur, la plaque positive est celle qui est reliee 

 au pole positif de la machine pendant la charge, et qui est le pole positif 

 pendant la decharge. 



(12) Le Congres recommande comme moyen de determiner le degi-e 

 d'incandescence d'une lampe, la methode proposee par M. Crova. 



Ces diverses propositions sont adoptees a I'unanimite. 



As an English equivalent of the above the Committee have adopted 

 the following resolutions, which they hope will meet with general ac- 

 ceptance. 



(1) The name of the practical iinit of work shall be the Joule. The 

 Joule is equivalent to 10^ C.G.S. units of work, ft is the energy ex- 

 pended during 1 second by a current of 1 ampere when traversing a 

 resistance of 1 ohm. 



(2) The name of the practical unit of power shall be the Watt. The 

 Watt is the rate of woi-king of a machine performing 1 joule per 1 

 second. The power of a machine would naturally be expressed in kilo- 

 watts instead of in horse-power. 



(3) The name of the practical unit of light intensity shall be the 

 Candle.' The Candle is equal to the twentieth part of the absolute 

 standard of light as defined by the International Conference of 1884. 



(4) The name of the practical unit of induction shall be the ' Quadrant.' 

 One Quadrant is equal to 10° centimetres. 



(5) The ' Period ' of au alternating current is the duration of a complete 

 oscillation. 



(6) The ' Frequency ' of an alternating current is the number of com- 

 plete oscillations per second. 



(7) The ' Mean Current ' through a circuit is the time average of the 



1 f^ 

 current and is defined by mean current^ ^1 idt, i being the current at 



TJo 



each instant of the time T. 



(8) The ' Effective Current ' io the square root of the time average of the 



square of the current. Thus, effective current=^ / < j-^ v^dt > 



(9) The ' Effective Electromotive Force ' is the square root of the time 

 avei'age of the square of the electromotive force. Thus, effective electro- 

 motive force =./< e^dt y ,e being the actual electromotive force at 



each instant of the time T. 



(10) The ' Impedance * is the factor by which the effective current 



' It will be seen that the Committee recommend the names ' Candle ' and ' Impe- 

 dance ' as the equivalents for the French terms ' Bougie d6cimale ' and • R6sistance 

 apparente ' respectively. With regard to the latter, they are of opinion that it is 

 desirable to restrict the term ' Resistance ' to actions purelj' dissipative. 



The candle is also very approximately equivalent to the English standard candle 

 and to one-tenth of the Carcel. 



