1835.] Composition of White Light . 179^ 



colours to insensibility of tRe eye arising from fatigue or 

 exhaustion ; because the preparation for this formation 

 commences instantaneously, and two colours, complemen- 

 tary to each other, as we have seen in a former experiment, 

 may be both exalted by the most rapid transition. 



I have before noticed that the motion of the eye-lids 

 preserves the power of the eyes to distinguish colours. 

 From some observations I have since made, I am disposed 

 to attribute this to the influence of the accidental colours 

 of the objects in view; formed in the eyes when they are 

 closed, though, from the rapidity of the motion, they are 

 not visible. In making some experiments with the green 

 centre of a hearth-rug, in order to determine the shortest 

 time in which its accidental colour might be seen, I found 

 that a beautiful crimson, approaching to scarlet, was pro- 

 duced, by looking at the rug only time enough to form a 

 distinct perception of its colour, which occupied less than 

 a second ; and that if the eyes were closed a little more 

 deliberately than when it is done by the usual involuntary 

 motion, the accidental colour was seen, before the eyes were 

 quite closed. Upon repeatedly opening and closing the 

 eyes, so as just to give time to form a distinct perception of 

 the primary and accidental colours in succession, I observed 

 that the colour of the rug, so far from being lessened in 

 intensity, was rendered more vivid than when the eyes 

 were first directed to it. 



The accidental colour in this experiment, is not correctly 

 complementary, in consequence of the more ready admis- 

 sion of the red than the violet light, through the eye-lids ; 

 after the accidental image has been some time formed, it 

 approaches nearer to its proper colour. P. C. 



To the Editor of the Records of General Science, 

 Weston Super Mare, July 16, 1835. 



Note hy the Editor. — It is an interesting circumstance, that 

 while so many of our pages have been devoted to inquiries 

 into the nature of light and its modifications, the same sub- 

 ject should be taken up by a foreign contemporary. M. 

 Plateau, in a very excellent paper published in the Annales 

 de Chimie et de Physique, Iviii. 337, proposes a theory for 

 the explanation of accidental colours, after disscugsing at 



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