834 PROFESSOR PIAZZI SMYTH ON COLOUR, 
38. OXFORD BLU E—continued. 

Solution of strength = Jy. This red of the Oxford blue is farther to the red than 
that of the Cambridge blue. 

Wave-number | Colour Region by | | 
Intensity. Te in Brit. Inch. | Wave-number. 
Light begins 0 25°19 33 223 | Crimson RED 
Maximum Rep LicHt 1 25°31 34 758 | Crimson RED 
Ends é . 0 2543 | 386 456 | Rep 
Light begins again 0 27°19 54 083 | GLAucoUS 
Maximum VIOLET 2 27:58 56 948 | BLUE 
End all 0 
28:08 60 248 | LAVENDER 
4. LITMUS. 
(9th March 1878.) 
A dark granulated solid, dissolving easily in water ; blue in small depths, 
verging to red for greater, in transmitted light, 
Solution 75357; is a light blue liquid, brightening the red, and dulling 
yellow and violet of Spectrum. 
Wave-number | Colour Region by 
Intensity. vr -in Brit. Inch. | Wave-number. 
Light begins 0 25°28 34 364 | Crimson RED 
Maximum Rep Licut ii 25-62 88 820 | SCARLET 
Beginning of faint dulness . + 25°81 41 034 | AMBER 
Brightens 2 : 4 26:12 44 267 | YELLOW 
Maximum Green light 5 26°41 47 304 | GREEN 
Maximum Blue. % 3 27°15 53 763 GLAUCOUS 
End all 0 28°04 59 988 | VIOLET 

Solution = sg55. Shows one burning red broad band, next a black band over yellow 
and citron; then a bright green band, and finally a faint blue band. 

25°30 34 626 Crimson RED 
25:58 | 38-344. | ScARLET 
25°75 40 388 | AMBER 
26:18 44 843 YELLOW 
26:60 48 972 | GREEN 
Darker and blue 26:90 51 653 GLAUCOUS 
End all . 27°96 59 453 | VIOLET 
ee a ee eee ee eee 
Light begins 
Maximum Rep Licut 
Light ends 
Begins again 
Maximum GREEN 
ow PrHOMO 

