CHAPTER V. 



NEW APPLICATIONS OF LIGHT PHOTOGRAPHY. 



O portrait, bright and wonderful ! 



Wrought by the sun-god's pencil true ; 

 What grace of feature, glance of eye ! 



The soul itself beams out from you. 



New marvel of a marvellous age ! 



Apelles old, whose'art 'twas said 

 Rivalled reality, than this 



Had never limned a lovelier head. 1 



THE improvements in the mode of production of light 

 for common use, discussed in the previous chapter, are 

 sufficiently new and remarkable to distinguish this cen- 

 tury from all the ages that preceded it, but they sink 

 into insignificance when compared with the discoveries 

 which have been made as to the nature of light itself, its 

 effects on various kinds of matter leading to the art of 

 Photography, and the complex nature of the Solar 

 Spectrum leading to Spectrum Analysis. This group of 

 investigations alone is sufficient to distinguish the 

 present century as an epoch of the most marvellous scien- 

 tific discovery. 



Although Huygens put forward the wave-theory of 

 light more than two hundred years ago, it was not ac- 

 cepted, or seriously studied, till the beginning of the 



1 The above translation of the Pope's Latin verse on Photography 

 is by my friend, Mr. F. T. Mott, of Leicester. 

 Expressa soils spiculo O mira virtus ingeni, 



Nitens imago, qnam bene Novumque monstrum ! Imaginem 



Frontis decns, vim luminum Naturae Apelles gemulns 



Refers, et oris gratiam. Non pulchriorem pingeret. 



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