388 abstracts: physics, electricity 



PHYSICS. — The relation of the horsepower to the kilowatt. Circular 34, 

 Bureau of Standards, 1912. 

 A unit of power should not vary in magnitude from place to place, 

 and hence the horsepower should be defined in such a way as to be equiv- 

 alent to a fixed number of watts. The Standards Committee of the 

 American Institute of Electrical Engineers in 1911 adopted the most 

 frequently used equivalent, namely, 746 watts, as the precise value of 

 the horsepower and this value is now recommended by the Bureau of 

 Standards. The "continental horsepower," used in Europe, is similarly 

 best defined as 736 watts. In accord with the trend of modern practice, 

 particularly in electrical engineering, it is recommended that the kilowatt 

 instead of the horsepower be used generally as the unit of power. 



J. H. Dellinger 



ELECTRICITY. — Electric wire and cable terminology. Circular 37, 

 Bureau of Standards, 1912. 



On account of the growing need for precise definitions in the field of 

 conductor terminology, the Standards Committee of the American Insti- 

 tute of Electrical Engineers requested the Bureau of Standards to pre- 

 pare a circular on the subject. As a result of extensive correspondence 

 and consultation it was found possible to formulate a reasonably con- 

 sistent body of definitions without introducing radical departures from 

 existing general practice. Seventeen of the most important terms have 

 been defined. 



It was found necessary to give the most care and thought to the terms 

 "strand" and "cable." In the strong preponderence of current opinion, 

 "strand" implies a component part of a cable or stranded conductor, 

 each part being either a combination of wires or a single wire. It fortu- 

 nately happens that this is precisely in accord with the non-technical 

 meaning of "strand." A "cable" is defined as either: (1) a stranded 

 conductor, i.e., a conductor composed of a group of wires; or (2) a com- 

 bination of conductors insulated from one another. The first kind of 

 cable may be either bare or insulated. The component conductors of 

 the second kind of cable may be either solid or stranded and the whole 

 may or may not have a common insulating covering. 



From the main terms defined, the minor germs should follow logically 

 and most or all of the confusion which has existed in this subject should 

 disappear. J. H. Dellinger. 



