AND THE THEORY OF LIGHT. 57 



84. Having already, without previously developing auy 

 formal theory, exhibited the process of reasoning which 

 compelled me to refuse my assent to the commonly re- 

 ceived theory of light, I will proceed to describe the experi- 

 ments, which served to demonstrate the above propositions, 

 just as they were made, and rude and elementary though 

 they sometimes were. The theory will develop itself out 

 of the experiments, and the above propositions will be 

 proved by the sum of the evidence adduced, although pos- 

 sibly not in the order announced. 



8^. The first thing then to be proved is, that colour can 

 be produced without the aid of refraction. 



The wafer experiment, the card experiment and the 

 candle experiment were so very interesting and, according 

 to the view which I had taken of them, so very instructive, 

 that I was resolved to make them the basis of my new 

 experiments — that is, to produce, if possible, the same 

 effects mechanically. But seeing that the whole optical 

 science of the day was so much opposed to my idea, I na- 

 turally felt some reluctance in attempting to verify it by 

 experiment. As, however, neither the emission theory, 

 nor the wave theory, nor the theory of complementary 

 colours, could account for the effects produced, I became 

 disposed to yield to my own convictions, and the more so, 

 as I could see no defect in my process of reasoning, after 

 having subjected it over and over again to the most rigid 

 scrutiny I could apply to it. 



86. Accepting it as a well established fact, that light is 

 not perceived until it falls upon and is reflected from some 

 material substance, I concluded that if a beam of white 

 light could be made to r-aove rapidly over a space which 

 reflected little or no light, I should be able to change the 

 colour of the light ; for, by thus reducing the number of 

 vibrations, I considered that the efi'ect would be analogous 

 to that produced by a refracting substance. At all events, 



SER. IJI. VOL. I. I 



