TABLE 92.— CHARACTERISTICS OF SOME CARBON ARCS* 



105 



Low intensity and high intensity carbon arcs 



Positive carbon 

 Low-intensity carbons 



10 mm low intensity 



12 " " " 



13 " " " 



High-intensity projection carbons 



6 mm "suprex" 



7 



9 

 11 

 13.6 



16 



' rotating positive 



High-intensity searchlight carbons 



10 mm rotating positive 



12 " " " 



16 " " " 



16 " " " 



20 

 32 

 40 



40 



SO 



70 



85 



115 



125 



150 



170 



225 



100 

 120 

 150 

 195 



Arc t 

 volts 



55 

 55 

 55 



37 

 37 

 40 

 58 

 55 

 68 

 78 

 75 

 75 



75 

 75 

 78 

 90 



Carbons 



Vertical trim ac and dc flame arcs 



Upper 



i"WF 

 Photo t 



¥ 2F § 



Lower 



ywF 



Photo t 



Amperes 



40 

 40 

 40 

 40 



Alternating-current high-intensity carbon 



A 



arcs 



Carbon 



7 mm 



8 mm 



9 mm 



Amperes 



65 

 80 

 95 



Arc 



volts 



26 ac 

 29 ac 

 26 ac 



Lumens per 

 arc watt 



14.9 

 15.7 

 16.3 



28.6 

 29.7 

 34.6 

 26.4 

 32.5 

 27.0 

 35.0 

 33.6 

 32.2 



32.3 

 33.0 

 32.0 

 31.5 



Lumens per 

 arc watt 



39 



55 

 50 

 44 



Lumens per 

 arc watt 



60.5 

 61.5 

 68.5 



* Data furnished by W. W. Lozier of National Carbon Co. 

 tional" white flame photographic carbons, rare earth cored. 



t All direct-current power. % "Na- 



§ "National" 2F carbon, neutral cored. 



TABLE 93.— EFFICIENCIES OF SOME EARLY INCANDESCENT LAMPS OF 



ABOUT 60-WATT SIZE" 



Lumens 

 per watt 



Edison's early carbon lamp 1.8 



Treated carbon lamp 3.2 



Gem lamp 4.0 



Nernst glower 5.0 



Tantalum lamp 4.9 



Osmium lamp 4.9 



Tungsten lamp (1907) 7.8 



Tungsten lamp (1949) coiled coil 14.0 



Life 



600 hr 



600 



600 



600 



900 



1,000 

 1,000 



"Forsythe, W. E., and Adams, E. Q., Bull. Denison Sci. Lab., vol. 32, p. 70, 1937. 



SMITHSONIAN PHYSICAL TABLES 



