84 APPENDIX. 



gold size and Brunswick black are most commonly used. 

 To form a cell, simply charge a camel-hair brush with the 

 varnish, and enclose with a broad black ring a small circular 

 apace on the centre of the slide. When quite dry, it is ready 

 for use. Place the object, with a small quantity of fluid, in 

 the cell ; and having lightly touched the edges of the thin 

 glass cover with gold size, drop it gently on the specimen ; 

 the superfluous fluid will escape over the sides of the cell, 

 and may be removed by small pieces of blotting-paper, 

 taking care, however, that none of the fluid is drawn from 

 the interior of the cell ; in which case an air-bubble would 

 immediately appear. To make the cell air-tight, gradually 

 fill up the angle formed by the edges of the cover with the 

 cell, by running several rims of varnish round it. In order 

 to prevent the cement from running into the cell and spoiling 

 the specimen, each layer should be dry before another is 

 placed upon it. 



The student should always have a stock of cells on hand 

 ready for immediate use. Dozens of these cells may be made 

 in half an hour by an ingenious little turntable, the inven- 

 tion of Mr. Shadbolt, and which may be obtained for a few 

 shillings. 



The limits of this little work have precluded us from 

 giving little more than general directions respecting the 

 permanent preparation of microscopic objects. Our object 

 has been merely to give a few plain instructions, which, if 

 carefully followed, will enable him to prepare some of the 

 most popular objects exhibited by the Microscope. 



THE END. 



ROBERT HARDWICKE, PRINTER, 1Q2, PICCADILLY, 



