132 Moonlight and Colour. 



Having made the preceding experiments in the manner 

 suggested, it will be interesting to notice how much the effect 

 of tinted moonlight may be increased by operating in a dark 

 room, with only one opening for the lunar rays. Under such 

 circumstances, if the moon be nearly full, and a piece of bright 

 red glass held opposite an opening of moderate dimensions, a 

 distinct dark red tint may be thrown on white paper, or linen, 

 but no noticeable colour can be communicated to dark objects 

 unless their surface is highly reflective. A looking-glass 

 shows the colour well, and, still better, the convex surface of a 

 white china cup, which has a good glaze. A striking effect 

 may also be produced by receiving the tinted light on a round 

 white glass bottle full of water, which in a red light becomes 

 "warm gules." Green glass succeeds very well, so does blue, 

 but the colour is less powerful. The strongest effect is ob- 

 tained by holding a good reflecting surface near the glass, but 

 a noticeable tint may be thrown across the room on a white 

 ground. 



Having obtained distinct coloration in this way, introduce a 

 lamp, turned down so as to yield scarcely any light, and then gra- 

 dually turn it up until the colours give place wholly or partially 

 to the homogeneous, yellowish-white light which the lamp 

 diffuses. By this means we get a notion of the strength or 

 weakness of lunar tints, but we have to consider their effects 

 from another point of view. 



In daylight we see coloured objects for the most part in 

 contrast or harmony with other colours, and the effect of each 

 is thus modified to a considerable extent. Thus a grey pattern 

 on a yellow ground looks violet, that being the accidental or com- 

 plementary colour of yellow. A blue ground, in like manner, 

 makes a grey pattern thrown on it appear tinged with orange, 

 which is the complementary of blue. All eyes that are not 

 very defective are sufficiently affected by complementary colours 

 to modify very materially the impression produced by surround- 

 ing objects, but tin- Bensitiveness of eyes to colour-action of 

 this or any other kind depends partly upon their constitution, 

 and very much upon the amount of intelligent exorcise their 

 owners hare given them. Most persons arc content to go 

 through life half blind, because they arc too lazy or too stupid 

 to make a rational use of the organs bestowed upon them. 



Bui even good and practised eyes differ much in sensitiveness 

 to particular coloure and in ability to be affected by accidental 

 ei. lours. Most people can seethe accidental colour of a blue 

 or red wafer held forafew moments in Btrong sunlight, but have 

 to look very steadily and for BOme time in order to sco it de- 

 veloped in a somewhat shady room. Moonlight is too feeble 

 to affect our visual organs much through accidental colours, 



