1183 
The numbers for / were obtained from those for « by a shift 
of 1' (the difference in the minimum deviation for the two wave- 
lengths). 
The final results are contained in the following table: 
D L Wp ah ee ee re Colour 
21030’ hom an Bag a A 29.5 red (weak) 
21045’ HOR ed rare 
2200’ 279 DEE | aos [ee yell 
15/ 424 | 69 31 te | green-yellow 
30’ OTN NE Pee 8.4 green | | 
rs ae NEE | 96 | 4 17.0 |. blue 
2300’ 41 | 9 4 en a of 
| | | ‚ white 
30 | 437 dn | 16.9 
2400’ =| _ 408 re ne ati CH en 
250’ | 362 98 2 | ayy eee 
i | 
In this table the letters have the following meaning: 
D angle of deviation; Z intensity of the light; W°/, and C°/, 
percentages of white and of colour; G the colour-number in Perntrr’s 
(Maxwk.1’s) colour-triangle, the last column gives the corresponding 
colour. 
Fig. 3 shows the dependence of Z on D; from which it appears 
that the refraction-theory gives a maximum at a distance of more 
than 22°30’. The observations on the other hand show, that the 
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3 
