432 Mr. F. Merrifield and Mr. E. B. Poulton on 



The absorption was more marked in the transaiitted 

 light. 



Yellow tissue-paper (also rolled round sticks). Violet 

 cut off and blue much diminished ; hardly any blue in the 

 transmitted light, and iu the thicknesses of paper rolled 

 round sticks. 



Golden yellow oat-straw gave a very similar spectrum, 

 the blue and violet being absorbed and the rest 

 unaffected. 



Urifaded Iright yellowish-green tissue-paper (also rolled 

 round sticks). The red shortened and dimmed ; the blue 

 and violet much absorbed. Transmitted light similar, as 

 also the reflected light from the paper round sticks. 



Bright yellowish- gj^een art muslin. A similar spectrum. 

 Not much difference between transmitted and reflected 

 light, except that two thicknesses produced far greater 

 effects in the former. 



Dull green reeds. Whole spectrum somewhat weakened, 

 the blue most and then the red. 



Yellow metallic surface of brass {Dutch gold), also rolled 

 round sticks. Appears to give a strong continuous spec- 

 trum, but the yellow colour is due to absorption of the 

 blue end. 



Dead rerds. The lightest of them gave a typical yellow 

 spectrum with absorption of the blue end only ; in the 

 others there was diminution of all other regions, although 

 the blue end was still most reduced. 



Tmmed cylindrical wooden sticks (probably deal). A 

 very similar spectrum ; the blue end was still more 

 absorbed than any other part, although less so than in the 

 dead reeds. 



Dirty white paint gave a very similar spectrum with 

 some absorption throughout, most in the blue, least in the 

 green. 



White paper rolled round sticks, white calico, shaved white 

 sticks all gave a strong continuous spectrum with no se- 

 lective absorption. 



Yellow glass (used as screen). Blue and violet cut off, 

 the rest unabsorbed. 



Deep) green, glass (used as screen). The green almost 

 unabsorbed. The whole of the blue end, and nearly all 

 the red and orange absorbed. 



II. Coloured backgrounds eniployed by E. B. Poulton and 

 those who worked with him. 



