100 The Microscope. 



glass, or otherwise arranged as may seeni best. But 

 before taking leave of " prepared slides/' a few words 

 must be added on a class of microscopic objects which 

 the reader has most probably met, and viewed with 

 surprise and curiosity. I mean the Microscopic Pho- 

 tographs. They may be classed as wonders of the 

 photographic camera, rather than of the microscope ; 

 but as they cannot be seen without the help of the 

 latter instrument, a notice of them may be considered 

 not out of place in the present work. 



A few specimens of these may generally be formed 

 in collections. To the unassisted eye they look much 

 like other objects mounted in balsam; all that is 

 visible on the slide is a neat little disc of thin glass, 

 with a tiny grey dot in its centre, smaller than a pin's 

 head. But the slide bears a label, oddly contrasting 

 with the scientific matters suggested to us by the 

 slides which we have hitherto considered, and showing 

 that the object ia a miniature of some well-known 

 engraving, portrait, or inscription. "We place it on 

 the stage, and see it magnified to the dimensions of 

 an ordinary book illustration, and appearing like a 

 tolerably good lithograph. An observer unaccustomed 

 to the microscope can scarcely believe that a number 

 of well-executed faces and figures, or several lines of 

 clearly legible printing, can be contained in a space so 

 extremely small ; and the ocular proof that it really is 

 so, affords much interest and surprise, and at the 

 same time conveys a tangible idea of the micro- 

 scope's power. These little photographs have ac- 

 quired considerable popularity; and I do not wish 



