ABSTRACTS OF TECHNICAL ARTICLES 479 



3. The alloy of 50 copper-50 iron can be satisfactorily tinned com- 



mercially. 



4. Within the rang:e of alloys studied, corrosion resistance decreases 



with increase of iron content. Various corrosion tests indicate 

 that these alloys might prove corrosion resistant in inland rural 

 districts, but that they are unsuitable for use in marine at- 

 mospheres and would probably be unsatisfactory in most 

 industrial atmospheres, particularly in regions near the sea 

 coast. 



A Study of the Electromagnetic Field in the Vicinity of a Radiator.^ 

 F. R. Stansel. The complete equations for the electromagnetic field 

 of an infinitesimal current element are given. The integration of these 

 equations is considered for the case of a finite radiator having an 

 empirical current distribution. Tables are included to facilitate 

 computation and consideration is given to difference in phase of the 

 current in various portions of the radiator. 



An Analysis of Theater and Screen Illumination Data J S. K. Wolf. 

 During the past twenty years much information on theater and screen 

 illumination has been accumulated. The significance and reliability 

 of these data are discussed in the light of known physical factors 

 influencing proper illumination. As a first approximation to a stand- 

 ard, it is suggested that the data indicate a value of 8 to 12-foot candles 

 as representing satisfactory illumination. Variation of required 

 illumination with screen size is analyzed, and a solution of the problem 

 is suggested. The brightness of screen surroundings also is discussed. 

 It is concluded that improvement in projection may be made by 

 stricter application of existing information but that further investi- 

 gations are desirable. 



^Proc. I. R. E., May, 1936. 

 ' Jour. S. M. P. E., May, 1936. 



