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92 



Marvels of the Universe 



Pliolo lii] 



[K. J. Spina, F.n.if.^. 



PART OF A DIATOM. 



This photo shows a small portion of the Diatom sho^vn at the foot of page 590. but under a much greater magnifying po\ver 

 of the microscope. Here the fine lines of the former photo are seen to consist really of minute dots. The scale of magnification 

 is 1.000 times the actual size. It is the summit of the photo-micrographer's ambition to thus resolve the lines into these dots. 



fact, this is one way of cleaning them. It is these " remains " that are of such interest to the micro- 

 scopist, for they are found in every variety of form, whether boat-shaped, circular, spindle-shaped, 

 or like a strip of tape, shaped as a basin or as a three-cornered hat. Sometimes forms are met with 

 twisted as a portion of a spiral. They all vary, too, in size, some only requiring a moderate-power 

 microscope to render them visible, whilst others need the highest of magnifications. But this is 

 not all. If the highest possible magnifying power be used, and every optical construction and 

 mechanical adjustment of the microscope be employed at its best, fine markings are revealed, called 

 " secondaries," or " secondary markings," which were invisible before. These consist of minute lines 

 ruled close together, dots or pearls and cavities. The wav in which these mirmte markings are 

 executed, their exquisite symmetry of design and their re.gularitv of arrangement, surpasses man's 

 comprehension, both as to the method by which the^' have been sculptured, as well as to compre- 

 hend or even speculate upon any possible purpose for which they can have been formed. It must 



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This photo shows a 

 are seen to be cavities- 

 portion shown. 



PORTION OF A DIATOM. 



smaller part of the Diatom shown above, but still more highly 

 -perforations of the valve. The scale of maeni heal ion here is 



[A". J. spdin. FJtM.s. 



magnified. In consequence the dots 

 3.200 times the actual size of the 



