CONTENTS XV 



309. Black-body spectrum intensities (/ x ), 50 to 20000 K 314 



310. " " " " " 25 to 6oo° K. . . . . . 315 



311. " " " " " 8oo° to 25000 K 316 



312. " : Auxiliary table, / x , any tem- 



perature 317 



313. Black-body spectrum intensities, J x , various temperatures C. . . . 317 



314. Spectral energy distribution, luminosity. Relative / x 318 



315. Luminosity relative to maximum value at each temperature . . .318 



316. Spectral energy distribution and luminosity. Luminosity factors . 319 



317. " " Variation with C 2 . 319 



318. Radiation emissivities : Relative emissive powers for total radiation. 320 



319. " Metals and oxides 320 



320. Some intrinsic properties of tungsten [300 to 3655 K.] .... 321 



321. Spectrum emissivity of tungsten (percentage) [1800 to 3400 K.] 322 



322. Temperature scale for tungsten [1700 to 2400 ° K.] 322 



323. Radiation characteristics of tungsten [500 to 3500 K.] .... 322 



324. and other properties of tantalum [300 to 3300 K.] . . 323 



325. " " " " " molybdenum [273°-2895° K.] . 323 



326. Relation brightness and color temperatures for various substances . 32$ 



327. Color minus brightness temperature for carbon 323 



328. Percentage emissivities of metals and oxides 324 



329. Emissivities, metals [Au, Ni, Ta, Pt, Ag, Fe, nichrome] 324 



330. Total radiation from bare and soot-covered nickel (watts/cm-) . . 324 



Cooling by Radiation, Conduction, and Convection 



331. Cooling by radiation and convection : At ordinary pressures . . . 325 



332. " different pressures . . . 325 



333. " Platinum wire in copper en- 

 velope 326 



334. Cooling by radiation and convection : Effect of pressure and temp. 326 



335. Conduction of heat across air spaces (ordinary temperatures) . . 327 



336. Convection of heat in air at ordinary temperatures 327 



337. and conduction of heat by gases at high temperatures . 328 



(a) s as function of a/B 328 



(b) (j> in watts per cm as function of absolute temperature . 328 



338. Heat losses from incandescent filaments 329 



(a) Wires of platinum sponge 329 



(b) " " bright platinum 329 



The Eye and Radiation 



339. Spectral variation of sensitiveness as a function of intensity . . . 330 



340. Threshold sensibility as related to field brightness 330 



341. Heterochromatic threshold sensibility 331 



342. Contrast or photometric sensibility 331 



