378 BRITISH SEA-WEEDS. 



Japan varnishj gold size, and tliin pieces of gutta percha, 

 or other materials used for forming the cell in wliich the 

 object is to be preserved in a fluid state. 



Knives, forceps, and scissors, of various constructions. 



Saucers with and without lips, watch-glasses, hair-pencils, 

 chamois leather for cleaning glasses. 



Having these ready, with the help of a hair pencil a 

 square or circular space is marked off with varnish, exactly 

 on the centre of a glass slide, forming a narrow band or 

 cell, an eighth of an inch or so in diameter. The varnish 

 in this process should be laid on very thin, and a second ^ 

 coat should not be given till the first is quite dry. A third 

 or fourth may be added according to the depth required for 

 the specimen. In making the gutta percha cell, we will 

 suppose a portion of that material cut out with a knife or 

 punch, of the same size and form as that mentioned for the 

 one of varnish. With this ready, place a glass slide on 

 the hob, or other stand at the fire-place, till it is of such heat 

 as will barely allow of handling. A pair of forceps will 

 hold it on one side, while with the other the gutta percha 

 is dropped on the centre, and pressed gently down with 

 some flat substance. AVhen quite cooled, the cell may be 

 further cemented to the glass by several layers of vaniish 

 applied to the exterior edge. 



