i6 



SOME HINTS ON THE PREPARATION AND 



Block-tin makes a very good cell, which may be attached to 

 the slide by Marine Glue the same as glass, and which will contain 

 fluid balsam quite as well ; but they must either be purchased of the 

 dealers, or made with a special and expensive punch. They are 



Fig. 10. Cells. 



more difficult to finish neatly than those of glass, and are only re- 

 commended by reason of their comparative cheapness. Brass 

 curtain rings may be substituted for them, and if carefully handled 

 in the mounting, may be found permanent and satisfactory ; but my 

 own experience has not been favorable toward the latter, either as 

 to convenience of handling, permanency, or neatness of appearance. 

 Fortunately we have a material, admirably adapted to making 

 cells, which any one can readily do for himself and at a trifling cost. 

 It is the ordinary white sheet wax used in artificial flowers and 

 which can be procured in three thicknesses, known 

 as "ordinary," "double thick, "and" pond lily." A punch 

 specially constructed for cutting cells from these 

 sheets, can be purchased from the opticians at the 

 small cost of a dollar and a half ; and enough to 

 mount a dozen or more slides may be punched in a 

 few moments. 



FIG. II. 

 WAX CELL PUNCH. 



A turn table is necessary for attaching these cells to the 

 slides, and some form of a self-centering one is recommended; the 

 enhanced first cost, being the only reason for hesitancy in making a 

 choice. A simple form of centering not ^//"-centering, mind you 



