206 THE MICROSCOPE. 
HOW TO DISPOSE OF EXCESS OF MEDIA ON SLIDES. 
Get the cover-glass in center of the slide on a turn-table; then 
spin a ring of the medium around the edge of cover, all that it can 
take without getting it on top of cover, using a small brush and 
scraper made of pine or linden, four or five inches long, one-fourth 
inch wide and one-eighth inch thick, one inch of the ends tapered 
down to one-sixteenth inch thick, and beveled like a carpenter’s 
chisel, which can be held on a slide while it revolves, so as to force 
the medium away from the mount or toward it. If the medium is 
too thick to spin around the mount, thin it with turpentine or 
benzol, if a solvent; or water, if it is a solvent of the medium. 
Then remove overplus of media with a scraper or a brush moistened 
in solvents, first with turpentine, finishing with benzine,* and 
patches of heavy muslin or linen wrapped double around a 
block of wood or cork about an inch square, with which the slide 
can be dried and polished, if mounted with balsam, damar, ete. 
When slides are mounted with Farrant’s medium, gelatin, glycerin, 
etc., proceed in the same manner, using water instead of oily 
solvents. Strips of thick harness leather, three-eighths or one- 
half inch wide and three or four inches long, can also be used with 
advantage to remove moisture, and clean and polish slides. 
Slides are thus easily manipulated into a neat condition to dry 
and harden, while avoiding the almost certain vexations of breaking 
or misplacing covers, or causing air-chambers in your mount while 
removing the hardened medium—a great drawback, and frequently 
the ruination of the most valuable specimens. 
It sometimes happens that a slide is more or less daubed, the 
medium spreading over a greater part of the slide while the micro- 
scopist is removing air-bubbles. Inevitable fibres which fly through 
the room are bound to get into sections, and innumerable kinds of 
dirt which stare us in the face. 
When the specimen is mounted, and a neat ring formed around 
it, the overflow or deluge of medium, sometimes unavoidable, is 
easily washed away with solvents, while fresh and soft, in the 
manner already described; but if laid away in such an unsightly 
condition to harden, it is much more difficult to remove and clean 
without ruining it. When plenty of medium is spun around the 
edge of the cover, it feeds the mount during the process of harden- 
ing. While the volume of medium is diminished through evapo- 
ration, a vacuum, or air chambers, is sure to form under the covers 
* As benzine is highly explosive, or inflammable, I keep only a one-dram vial of it 
while using a lamp, and have no fear of using in this manner. 
