AND THE THEOllY OF LIGHT. 93 



allowed — wliich no created being, no one but a divine 

 arcbitect could contrive or conceive. For example : 



Tbe phenomena of thin plates which in the hands of 

 Newton have received a philosophical importance, from 

 having led him to invent his celebrated theory of fits of 

 easy transmission^ and fits of easy reflection^ is by the 

 experiments on the chromascope brought more within the 

 range of investigation. In producing these phenomena 

 nature simply places two or more transparent plates in 

 different planes^ or at different angles, to the incident 

 light, the one plane reflecting no-light, or virtually causing 

 a shadow, the other plane reflecting light, and colouring 

 that shadow, by this simple expedient performing the 

 same operation which we attempt to do by our diagrams 

 in motion. Our motion produces on the light not only 

 the effect of vibrations, but the light and shade, when iu 

 motion, produce an effect similar to that resulting from 

 the geometrical construction of a natural body, composed 

 of thin plates. In our method of operating, a slow motion 

 gives rise to one colour, and a quick motion to another . 

 but the natural process yields the same results by different 

 means. Nature analyses force; it 'does not resolve a com- 

 pound substance into its constituent parts; on the con- 

 trary, it may be rather said to compound a simple sub- 

 stance; or in other words, natural objects are all con- 

 structed so as to reflect or transmit more or less of this 

 impinging force, which we call light, and all the colours 

 in nature are produced by the combination of one simple 

 uncompounded substance with the negative element, which 

 is now demonstrated to be not only an essential but a 

 coordinate element of colour with the positive. 



144. The celebrated phenomena of soap bubbles, which 

 have amused the young and the old by the charming play 

 of colours on their surface, receive also an easy solution 

 by the same process of reasoning. 



