148 Experiments with Lord Rayleiglis Colour Box. [June 5, 



Number 2 



March 4, 1889 -2 



Jan. 20, 1890 



April 23, 1890 -1 



Number 4 



March 5 S 1889 +5 



May 6, 1890 -3 



Number 9 



March 6, 1889 -4 



March 20, 1889 -3 



April 25, 18yO -2 



May 7, 1890 -7 



Number 14 



March 6, 1889 -7 



May 5, 1890 -6 



Number 15 



March 6, 1889 +1 



May 6, 1890 +3 



Number 21 



March 20, 1889 -6 



May 2, 1890 -8 



Number 25 



March 21, 1889 +4 



May 6, 1890 + 3 



Number 26 



March 24, 1889 -2 



May 6, 1890 -7 



Most of these observations show no change, and are indeed remark- 

 ably consistent. I must except, however, number 4, who is a very 

 irustworthy observer; and number 26 (Professor Dixon). In the 

 latter case, a change seems almost certain either in his eye or in 

 mine. We both observe, however, as Clerk Maxwell has done, that 

 the matches are not quite the same according as one looks straight at 

 the coloured patches, or a little to one side ; this would support the 

 view that the absorption in, the yellow spot plays an important 

 part. 



There is no evidence as to a difference in reading between the right 

 and left eye, except in one case. Generally speaking, the reading 



