Tables 375, 376. 



TRANSMISSIBILITY OF RADIATION. 



TABLE 375. — Color Screens. Jena Qlasses. 



307 



Kind of Glass. 



Copper-ruby 

 Gold-ruby . 



Uranium . 



Nickel . . . 

 Chromium 



Green copper , 

 Chromium . 

 Copper chromium 

 Green-filter 



Copper . . , 

 Blue-violet 



Cobalt 



Nickel 

 Violet 

 Gray. 



Maker's 

 No 



2728 



459"' 

 454'" 

 455"' 



440"' 



414"' 

 433"' 

 431"' 

 432"' 

 436"' 

 437"' 

 438'" 

 2742 

 447'" 



424 

 450'' 

 452'' 

 444" 



445" 



Color. 



Deep red 

 Red . . 



Bright yellow . . . 



^ Bright yellow, fluo- 

 I resces. 



Bright yellow-brown 



Yellow-green . . . 

 Greenish-yellow . . 



Green 



Vellow-green . . . 

 Grass-green . . , 

 Dark green . . . . 



Blue, as CUSO4 . , 

 Blue, as cobalt glass 



Blue 



Dark violet . . . 



I Gray, no recog- 

 f nizable color 



Region Transmitted. 



Only red to o.6fi 



J Red, \ ellow ; in thin layers also 

 I blue and violet. 

 J Red, yellow, green to Eb ; in / 

 ] th.n layer also blue ) 



k Red, yellow, green (weakened), 



/ blue (very weakened) 



Yellowish-green 



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

 Green, yellow, some red and blue . 

 Yellowish-green, some red . . . 



Green 



Green (in thin sheets some blue) . 



Green 



Green, blue, violet 



Blue, violet 



J Blue, violet, blue-green (weak- J 



I ened), no red \ 



Blue, violet, extreme red . . . . 

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

 Violet (G-H), some weakened . . 



All parts of the spectrum weakened 



Thick- 

 ness, 

 mm. 



1-7 



16. 



II. 



10. 



5- 

 2-3 



2-5 



5- 

 5- 



5-12 

 5- 



2-5 



%' 



7- 

 0.1 -J 

 0.1-' 



See " Uber Farbglaser fiir wissenschaftliche und technische Zwecke," by Zsigmondy, Z. fiir In- 

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

 filter," by Grebe, same volume. 

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



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'", 31"^. 

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

 2728, r.y 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-color 

 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 in 



different meltings. 

 See also "Atlas of Absorption Spectra," Uhler and Wood, Carnegie Institution Publications, 1907. 



TABLE 376.— "Water. 

 Values of a in I = Iq e ***, d in c. m. lo; I, intensity before and after transmission. 



First 9; Kreusler, Drud. Ann. 6, tgoi; next Ewan, Proc. R. Soc. 57, 1894, A'schkinass, Wied Ann.. 



5S> iSps; last 3, Nichols, Phys. Rev. 1, i. 

 See Rubens, Ladenburg, Verb. D. Phys. Ges., p. 19, 1909, for extinction coeft., reflective power and 



index of refraction, i /( to iS ^. 



8.VIITHS0NIAN Tables. 



