820 PROFESSOR PIAZZI SMYTH ON COLOUR, 
3. Judson’s Dyes, MARONE RED. 
COAL-GAS LUMINOUS FLAME, as foundation. 

Wave-number | Colour Region 


LNB SST ce in Brit. Inch. | by Wave-nuimber. 
Falsestedolare yu gO |. ape bP 0 2436 | 29 087 | Ultra Rep 
First true red light . 4 } ; ; 1 25°18 33 102 | Crimson RED 
Slit, by sodium light, Istside . . . 11 26°01 | 43 015 | Yellow 
. 2d side . : : 11 26°03 43 203 | Yellow 
Maximum Licut, YELLow . , ; : 12 26:03 43 403 | Yellow 
End of all light at violet .  . ae | be 0 28:46 | 65 712 | Lavender 

Solution of strength = 4,5. Admits only one broad, red to yellow, band. 



Ieht beome | Ge ee 0 25°34 | 35 162 | Rep 
Maximum LIicutT r ; : ; : 8 25°82 41 152 | AMBER 
Ends. ; ; ; ‘ : e : 0 26:13 44 366 | YELLOW 

Solution of strength = 31,5. Shows one red band only. 

Light begins. : : ‘ ; ‘ 0 25°30 34 626 | Crimson RED 
Maximum Licut : . : : ; 6 25°72 40 016 | AMBER 
Endall_ .. ; : . : ; : 0 25°95 42 571 | AMBER 


Solution of strength = J,. 


Light begins. 4 F ; : , 0 25°33 30 026 | RED 
Maximum Licut ; i : : : 4 25°62 . 38 820 | ScARLET 
Endall . f ‘ - , ‘ . 0 25°78 40 717 | AMBER 



| 4. Judson’s CARDINAL RED. 
Like the above, but rather yellower. 
5. Judson’s Dyes—MAGENTA RED. 



COAL-GAS LUMINOUS FLAME, as foundation. 

Wave-number | Colour Region by 



Intensity. die in Brit, Inch. | Wave-number. 
False red glare . : a 4 ; : 0 24°86 29 087 | Ultra Red 
First true red ight . ‘ : : ; aD 25°18 33 102 | Crimson RED 
Shit, by sodium light, lst side . : : i) 26°01 43 015 | Yellow 
Ay 5 2d side. : : ila 26:03 43 203 | Yellow 
Maximum Licut, YELLow . : : ; 12 26:03 43 403 | YELLOW 

End of all light at violet . : : : 0 28°46 62 712 | Lavender 



