812 PROFESSOR PIAZZI SMYTH ON COLOUR, 
COBALT-BLUE GLASS—continued. 

FOUR COBALT-BLUE GLASSES INTERCEPT. 




Intensity, Wave-number | Colour-Region by 
Max. =10. fs in Brit. inch. | Wave-number. 
Light begins at ; : MA 0:0 24:930 | 30 960 | Crimson RED 
Rises more decidedly at. : : : 1:0 25060 | 32 938 | Crimson RED 
Maximum Rep Licutat . : : , 22 25175 | 34 807 | Crimson Rep 
Shade ends sharply . : ; : : 0-0 25298 | 36 900 | RED 
After long dark space, faint green begins. 0:0 26030 | 45 147 | Crrron 
Said faint green band ends : i ' 0-0 267150 | 46 253 | CrrRon 
Light begins again Grreenish-black ; : 0°0 26545 | 49 826 | Citron 
Green-black shade ends. : : : 1:2 26°930 | 52 632 | Glaucous 
Maximum Buve Licut 4 F ; : 26 27260 | 55 127 | BLUE 
Violet light begins. ; : ; ‘ 15 27°720 | 58 720 | VIOLET 
End of all light ; . : ; 3 0:0 28°300 | 63 452 | LAVENDER 



Eight cobalt-blue glasses narrow and still farther remove apart the red and the blue bands 
of light, thus— 
Red band culminates at 36,200 Wave N*., or Between a and A, Solar. 
Blue band culminates at 56,660 Wave N*., or Between F and G, Solar. 
BLUE-LILAC GLASS. 


COAL-GAS FLAME’S CONTINUOUS SPECTRUM (REPEATED). 
False glare from internal reflections . : 0°5 24°642 | 26 596 | Ultra Rep 







True but faint black-red ight . ; : 0:3 24°965 | 30 864 | Crimson RED 
Strong red light, seen at. 4 : : 3°0 25:145 | 34 305 | Crimson Rep 
D slit, red side thereof , : : : 9-0 25°823 | 42 827 | AMBER 
»  yellowside . : . : ale oo 25°873 | 43 384 | YELLOW 
Maximum LIGHT : : : : : 95 25940 | 44 053 | YELLow 
Green light ends, blue begins at ; : 9-0 26220 | 46 948 | CrTRoN 
Blue light ends, violet light begins. 5 30 29°670 d8 140 | VIOLET 
All light ends at ; P : 0:0 28°430 | 64 516 | LAVENDER 
ONE BLUE-LILAC GLASS INTERCEPTS. 
False glare begins. : ' , 0-1 24.730 | 27 933 : | Ultra, Rip 
True lngiored hight begins ; ; : 0-2 24-970 31 546 Crimson RED 
Strong red light ’ ; : : : lari 25:170 | 34 722 | Crimson RED 
Full red light : ; : : : : 3°3 25:270 | 36 364 | RED 
Red colour ends, Maximum Licut, Green- 
yellow, begins : : : : : T4 25900 | 43 764 | YELLow 
Grass green. ; : : , : 50 26430 | 48 733 | Gruen 
Blue begins : : : : : ; 33 26°840 | 52 002 | Glaucous 
Violet begins. ; : 4 , ; 25 27°750 | 58 928 | VioLEer 
Violet colour, rich . ; 3 ; F 1:0 28°230 62 854 | LAVENDER 
End of all light : , ; ; ‘ 0:0 28°387 | 64 392 | LAVENDER 



