28 THE MICROSCOPE 



be pulled from the wing and remain upon the paper. If now the 

 paper be divided^ and a clean cover-glass of the chosen size be 

 taken, it will be found that by breathing upon the cover, and then 

 at once putting down upon it first one and then the other of the 

 papers, scale side to the glass, the scales will adhere to the glass 

 cover, and then, by gently warming over a spirit-lamp one of the 

 slips prepared as described, the ring of cement will be softened, 

 and the cover-glass with scales may be pressed closely to it, and 

 when cold all will be found firmly fixed. If it is desired to mount 

 a small piece of the wing, see that the cell is sufficiently deep, and 

 then, placing the wing in the centre of the cell ; by warming the 

 cover-glass, and at once putting it down on the cement-ring, it will 

 attach itself firmly, and may be thus put on one side. In 

 mounting portions of butterflies' wings, it will be found that a 

 more pleasing effect will be produced by arranging it in such a 

 manner that the light will fall on the scales from a certain direc- 

 tion, which should be first ascertained, and the piece of wing 

 arranged on the sUde accordingly. 



For pure diatom gatherings or deposits that it is desired to 

 mount dry, it is only necessary, after sufficient cleaning and wash- 

 ing, to put a drop of the fluid containing them upon a cover- 

 glass, and allowing this to dry, not by heat, but by slow evapora- 

 tion ; then warming the slide and cell as described for butterfly 

 scales ; the cover may be pressed down and securely fixed. It 

 will be noticed that in all these processes either cover-glass or 

 slides must be warmed. This will be found one of the most 

 important advantages of this method, for it will prevent any possi- 

 bility of fungoid growths from imprisoned moisture, and the slides 

 will probably be permanent objects of interest. 



We will now try to give a few examples of dry mounting, 

 where a deeper cell is required than can possibly be made with 

 cement. Make as before a ring of cement upon a glass slip, pro- 

 vide cells of cardboard, metal, glass, etc. ; make the slip hot to 

 soften the cement, and the cell may be pressed on, and when cold 

 will be found fixed, and may at once be used for any object of 

 which it is advisable to show both sides. Of this class of objects 

 are some of the polyzoa, ferns with fructification and hairs, and 

 leaves with hairs or scales on both sides. Should the object be 



