196 



Table 1 92. 

 TRANSMISSIBILITY FOR RADIATION. 



Color Scieens. Jena Glasses. 



Kind of Glass. 



Maker's 

 No. 



Color. 



Region Transmitted. 



Thick- 

 ness, 

 mm. 



Copper-ruby 

 Gold-ruby . 



Uranium . 



Nickel . . . 

 Chromium 



Green copper . 

 Chromium. . 

 Copper chromium 

 Green-filter 



Copper . . , 

 Blue-violet 



Cobalt 

 Nickel 

 Violet 

 Gray. 



2728 

 459'" 

 454°^ 

 455"^ 

 440°^ 



414"' 



433"" 

 431 in 



432'" 

 436"' 

 437"^ 

 438"^ 

 2742 



447'° 



424^ 



450' 

 452" 

 444^ 

 445" 



Deep red 

 Red . . 



Bright yellow . . . 



I Bright yellow, fluo- 

 I resces. 



Bright yellow-brown 



Yellow-green . 

 Greenish-yellow 

 Green .... 

 Yellow-green . 

 Grass-green 

 Dark green . . 



Blue, as CUSO4 

 Blue, as cobalt glass 



Only red to o.6fi 



I Red, yellow ; in thin layers also 

 j blue and violet. 

 ( Red, yellow, green to Et ; in ) 

 J thin layer also blue J 



1-7 



Blue . . 

 Dark violet 



I Gray, no recog- J 

 j nizable color ) 



i Red, yellow, green (weakened), ) 

 ( blue (very weakened) ) 



Yellowish-green 



Red, green ; from 0.65-. 50^ . . . 



Green, yellow, some red and blue . 



Yellowish-green, some red . . . 



Green 



Green (in thin sheets some blue) . 



Green 



Green, blue, violet 



Blue, violet 



Blue, violet, blue-green (weak- ) 

 ened), no red J 



Blue, violet, extreme red . . . . 



Violet (G-H), extreme red . . . 



Violet (G-H), some weakened . . 



All parts of the spectrum weakened 



16. 



II. 



10. 

 5- 

 2-3 



2-5 



5- 

 5- 



5-12 

 5- 



2-5 



%' 



7- 

 0.1-8 

 0.1-3 



See " IJber Farbglaser fiir wissenschaftliche und technische Zwecke," by Zsigmondy, Z. fiir la 



strumentenkunde, 21, 1901 (from which the above table is taken), and "Ober Jenenser Licht 



filter," by Grebe, same volume. 



(The following notes are quoted from Everett's translation of the above in the English edition o: 



Hovestadt's " Jena Glass.") 

 Division of the spectrum into complementary colors : 



1st by 2728 (deep red) and 2742 (blue, like copper sulphate). 

 2nd by 454"' (bright yellow) and 447"' (blue, like cobalt glass). 

 3rd by 433'" (greenish-yellow) and 424'" (blue). 

 Thicknesses necessary in above: 2728, 1.6-1.7 mm.; 2742, 5; 454"^, 16; 447"^, 1.5-2.0; 433" 



2-5-3-5; 424"'. 3 mm. 



Three-fold division into red, green and blue (with violet) : 

 2728, 1.7 mm. ; 414'", 10 mm.; 447'", 1.5 mm., or by 

 2728, 1.7 mm. ; 436'", 2.6 mm. ; 447"', 1.8 mm. 

 Grebe found the three following glasses specially suited for the additive methods of three-colo: 

 projection : 



2745, red ; 438'", green ; 447'", blue violet ; 

 corresponding closely to Young's three elementary color sensations. 

 Most of the Jena glasses can be supplied to order, but the absorption bands vary somewhat ii 



different meltings. 



See also " Atlas of Absorption Spectra," Uhler and Wood, Carnegie Institution Publications 

 1907. 



Smithsonian Tables. 



