39 



TABLES 378-379. 

 REFLECTION AND ABSORPTION OF LONG-WAVE RADIATIONS- 



TABLE 378. Long- wave Absorption by Gases. 



Unless otherwise noted, gases were contained in a 20 cm long tube. Rubens, Wartenberg, Verb. d. Phys. Ges. 

 13, P- 7Q6, IQU. 



* Tube 40 cm long. 



t Pentane vapor, pressure 36 cm. 



TABLE 379. Properties with Wave-lengths 108 M . 



Rubens and Woods, Verb. d. Phys. Ges. '13, p. 88, 1911. 

 With quartz, 1.7 cm thick: 60 to 8o/x, absorption very great; 63/1,99%; 82/1,97.5; 97M. 83. 



(a) PERCENTAGE REFLECTION. 



Wave-length. 



X = 82/Z*.. 



X = io8/it- 



T ; land 

 spar. 



Marble. 



43- 



25.8 

 20.3 



Sylvile 



36.0 

 19-3 



KBr 



82.6 

 SX.l 



Kl 



29 6 



35-5 



5"' Glass. Water. Alcohol 



te 



19.7 



20.2 



19.2 



9.6 



II. 6 



* Restrahlung from KBr. 



f Isolated with quartz lens. 



(b) PERCENTAGE TRANSPARENCY. 

 Uncorrected for reflections. 



Solid. 



Thickness. 



Transparency. 



Liquid. 



Thickness. 



Thickness 

 precipi- 



liquid. 



Trans- 

 parency. 



Paraffin 



Mica 



Hard rubber 



Quartz 1 1 axis 



Quartz, amorph 



Rock salt 



Fluorite 



Diamond 



Quartz J_ axis 



3-03 



0.055 



0.40 



2.00 

 3-85 

 0.21 

 0-59 

 1.26 

 2.00 



'4:8 



57-o 

 16.6 

 39-o 

 62.6 



o 

 21. 5 



5-3 

 45-3 

 81.3 

 66.4 

 49.8 

 35-5 

 29.0 



Benzene . . . 

 Ethyl alcohol. . . 

 Ethyl ether .... 



Water 



Water 



Vapors: 



Alcohol 



Ether 



Benzene ... 



Water 



CCh... 



I. 00 



0.158 

 0.158 

 0.029 

 0.044 



2.00 

 2.00 



2.00 

 4.00 



2.00 



0.023 

 0-350 

 0.063 



O.2I 



56.8 

 7-9 

 37-1 

 25.8 

 13.6 



88 

 33-S 



IOO 



19.6 



IOO 



(c) TRANSPARENCY OF BLACK ABSORBERS. 



Method and wave-length. 



Black silk 



paper, 

 .025 mm thick 



Opaque black 



paper, 

 o.i i mm thick 



0.4 mm thick. 



Spectrometer 



Fluorite " restrahlung " 

 Rock salt "restrahlung" 

 Quartz lens isolation 



2/4 



4 

 6 



12 

 26 



52 

 108 







0.9 

 1.7 



8.2 

 24.2 



46-0 

 61 . 5 







o 







1.4 



3-2 



.6 



0.5 

 8.6 

 16.0 

 37-6 

 76.7 

 91-3 

 91.5 



SMITHSONIAN TABLES. 



