856 PROFESSOR PIAZZI SMYTH ON COLOUR, 
1. OXALATE OF CHROMIUM AND POTASSIUM—continued. 

Solution ;}> tried; though so weak in colour to the eye, it notably dulls the green— 
cuts off the violet and the yellow, leaving the red pure and bright. 

Wave-number | Colour Region by 
Intensity. in in Brit. Inch.| Wave-number. 
| Red black light begins. 5 : 5 25:27 34 223 | Crimson RED 
Maximum brightest Rep light 25°70 | 39 777 | ORANGE 
0 
: 6 
Red light ends, green begins. : } 5 26:07 43 802 | YELLOW 
Green ends, blue begins : : ‘ 3 26°85 51 177 | Guaucous 
| End all 0 27°73 | 58 038 | VIOLET 

Solution 335. Though colour is so pale, yet the spectrum is very strongly banded. 

25°26 34 095 | Crimson RED 
25°65 39 170 | ORANGE 
26:02 43 309 | YELLOW 
26°22 45 249 | CrTRON 
26°46 47 710 | GREEN 
26°85 51 177 | GLaucous 
27°38 55 463 | BLUE 
Red light begins 
Maximum Rep Licutr 
Red light ends in dark haze 
Middle of dark haze band . 
End of dark band 
Green light ends, and blue ‘begins 
End all 
COWNMFDYP FP O&O 


Solution = ;3,5. A fine line clearly seen in the red band: a red band and a 
green-blue band are now the only spectral lights. 


Red light begins 25°30 34 626 | Crimson RED 
Fine black line!!! 25°42 386 311 | Rep 
Maximum Rep Licut : ; 25°60 38 344 | ScARLET 
25°76 40 502 | AMBER 
26:00 43 103 | YELLOW 
26°17 44 743 | YELLOW 
26°53 48 379 | GREEN 
26°92 51 813 | Guaucous 
2 25 54 496 | GLaucous 
Shady ending of red in black light 
Sodium line, made in gas flame . 
Chief blackness of dark band 
Shady ending of dark band 
Maximum of § green-blue light 
End all : , 
Sons rFonw Ff FS 


Solution 4. The line in the red is now very black, as well as neat and sharp, while the 
spectrum shows only as to light a red band and a fainter green-blue band. 



Diary 34 223 | Crimson RED 
25-42 36> 311 > |aReD 
25°46 36 928 | RED 
25°65 39 170 | ORANGE 
26°73 50 100 | Guaucous 
26:90 51 653 | GLAUCOUS 
27:09 53 305° | Guavcous 
Red light faintly begins 
Strong black spectral light 
Maxmum Rep Licut 
Red light ends in hazy black 
Light begins again hazily and greenly 
Maxnroum of such faint light 
End all 
ONOrF B® we 



