32 



MODE OF MOUNTING SPECIMENS. 



The algologist must now call in the aid of. doublets, or 

 of the compound microscope. 



In examining plants with the compound microscope, 

 if it be not intended to preserve the specimen, it is suf- 

 ficient to place it on a slip of glass, with a drop of water, 

 and cover it with another very thin piece of glass or 

 mica, when it is ready for examination. When it is 

 intended to preserve the specimen for further observa- 

 tion, or as a type of the species, the fragment must be 

 mounted in a more permanent manner. 



The plan most generally used by English microsco- 

 pists, is to make cells on glass slides, by drawing lines 

 with a camel's-hair brush dipped in varnish, or japanner's 

 gold-size, so as to enclose circular or quadrangular spaces. 

 When the varnish is dry, the cell is filled with some 

 preservative fluid, in which the object is placed, and 

 then covered with a thin piece of glass, of suitable size 

 and figure. The edges of the glass cover are coated with 

 varnish, to secure it to the slide, &c, and to prevent 

 the preservative fluid from evaporating. 



The glass slides and covers are sold at a moderate 

 price by the opticians, assorted in boxes. The former 

 are most commonly three inches long by one inch in 

 width. The algologist should write on the end of the 

 glass slide, with a writing- diamond, the genus and spe- 

 cies, with such other particulars as date, place where 

 found, &c, &c. 



