440 
CAPTAIN ABNEY AND MAJOR-GENERAL BESTING 
as yellow ochre diluted or mixed with white or black. The red about C, and below, 
appeared to him as yellow mixed with increasing quantities of black. A very 
interesting feature in his case is that one part of the spectrum which we definitely 
determined to be at X 5020, scale number 51, is to him absolutely neutral in colour. 
He describes all tints on one side of this point as being composed of blue, and on the 
other of yellow, mixed in each case with varying proportions of white or black. 
Dr. Pole is a most accurate observer; in very nearly every case did his three 
observations of intensity come to precisely the same point on the scale. Fig. 6, Plate 24, 
shows the comparison between his curve and ours. From this it would appear that 
there is a deficiency both in the red and green. To us his neutral point appeared a 
cerulean-blue, which to make white requires the addition of a large proportion of 
The colours of the illuminated shadows for different parts of the spectrum he 
described as follows :— 
Candle. 
Spectrum. 
At 52 spectrum scale 
Yellow. 
Blue. 
51 
Yellowish. 
Blue. 
50 
Certainly yellow, but grey. 
Grey, slightly blue. 
49 
Grey. 
Grey. 
47 
Grey, with a trifle of blue. 
Yellowish. 
45 
Paine’s grey. 
Decided yellow. 
It thus appears that at 49, which is A. 5386 in the spectrum, the shadows seem of 
f he same tint to Dr. Pole, while to us at that point the candle light appeared burnt 
sienna, and the spectrum light emerald-green, whilst the colours of the shadows 
appear to us the same at 46-g or about D. 
