t 



of the prismatic Colours to beat and illuminate Objects. 26 



In the blue rays, very well. 



In the indigo rays, not quite so well as in the blue. 



In the violet rays, very imperfectly. 



3^ Experiment. Green paper. 



Red. I fix my attention on many faint points, in a space 

 between two bright double points. 



Orange. I see those faint points better. 



Yellow. Still better. 



Green. As well as before. I see remarkably well. 



Blue. Less bright, but very distinct. 



Indigo. Not well. 



Violet. Bad. 



^th Experiment. A piece of very clean turned brass. 



R. I remark several faint luminous points between two bright 

 ones. The colour of the brass makes the red rays appear like 

 orange. 



0. I see better, but the orange colour is likewise different 

 from what it ought to be ; however, this is not, at present, the 

 object of my investigation. 



Y. I see still better. 



G. I see full as well as before. 



B. I do not see so well now. 



1. I cannot see well. 

 V. Bad. 



5th Experiment. A nail. 



R. I remark two bright points, and some faint ones. 



O. Brighter than before ; and more points visible. Very 

 distinct. 



Y. Much brighter than before; and more points and lines 

 visible. Very distinct. 



Mm 2 



