OR COLOUR BLINDNESS. 
TaB.e JI. 
Experiments with Polarized Light. 
177 
observation. 
Degrees of the 
Nos. of order of 
— 
BE Scarasaen | 
13 
circle. 
Colours according to my sight. 
Circle—right. 
Blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Whitish blue. 
Bluish white. 
Yellowish white. 
Whitish yellow. 
Light straw yellow. 
Darker straw yellow. 
Straw yellow. 
Deeper yellow. 
Deeper yellow. 
Deeper yellow. 
Brass yellow. 
Lemon yellow. 
Dull deep lemon. 
Deep dirty yellow. 
Light brown yellow. 
Fawn yellow. 
Deep fawn yellow. 
Chocolate brown. 
Red chocolate. 
Purple lilac. 
Violet purple. 
Indigo. 
Lapis lazuli. 
Prussian blue. 
Deep azure. 
Circle—left. 
Greenish yellow. 
Deeper greenish yellow. 
Deeper greenish yellow. 
Deeper greenish yellow. 
Brown yellow. 
Chocolate brown, 
Lilac brown. 
Purplish lilac. 
Lilac purple. 
Fine violet. 
Lapis lazuli blue. 
Less deep blue. 
Cobalt blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Sky azure. 
Hazy blue. 
Dull grayish blue. 
Grizzle blue. 
Gray blue. 
Dull blue. 
Bluish gray. 
Yellowish blue. 
Yellowish green white. | 
Very light greenish yel. 
Dull white. 
Light greenish yellow. 
Greenish yellow. 
Yellow a little greenish. 
Fine yellow, 
Colours according to the daltonian. 
Circle—right. 
Blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Bluish white. 
Undecided white. 
Dull white. 
White less dull. 
Fine white. 
Yellowish deal wh. 
Yellowish. 
Fine yellow. 
Fine yellow. 
Greenish yellow. 
Orange yellow, 
Yellow. 
Dead yellow. 
Greenish yellow. 
Light green. 
Fine grass green. 
Walnut-leaf green. 
Reddish green. 
Fine red. 
Fine deep blue. 
Same blue. 
Same blue. 
Lightish blue. 
Prussian blue. 
Same blue lighter. 
Circle—left. 
Straw yellow. 
Darker yellow. 
Darker yellow. 
Lighter yellow. 
Light reddish, 
Fine red. 
Finer red. 
Undecided blue. 
Deep blue. 
Blue like No. 9. 
Like No. 9. 
Like No. 9. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Lighter blue. 
Very light blue. 
Lighter blue. 
Very light blue. 
Grayish blue. 
Whitish blue. 
White gray. 
Weak bluish white. 
Dull white. 
Dull white. 
Yellowish white. 
Undecided yellow wh. 
Weak yellow. 
Light yellow. 
I chose rather to pass thus from one colour to another by 
a gradual transition than to proceed by abrupt intervals, which 
would have given me more decided results. 
In verification I 
have noted the colours of the two circles for the first sixty de- 
grees of the second quadrant, although they were only the re- 
petition of those which we had obtained in the first, with the 
sole difference of a change of their positions. 
Allowance being made for the very great difficulty which is 
met with when a tint little different from another belonging to 
the same colour has to be specified, it will be seen by inspection 
of this table that D *** sees the blue, white and yellow as we 
do; but that he mistakes in the purple, lilac and brown, con- 
founding them with red and blue. 
Mr. Taylor and I noted the yellow and blue tints of the six- 
teenth observation as equal in brightness, and the daltonian 
made the same remark on the tints of the same name of the 
thirty-first reading, which is not distant from them 90°. It re- 
VOL. IV. PART XIII. 
N 
