1893] NEW-YORK MICROSCOPICAL SOCIETY. 83 



niounts can be made without the employment of any cell. Spin 

 with the turn-table a guide ring of India ink, about one-sixteenth 

 of an inch larger in diameter than the intended cover, upon 

 either the upper or lower surface of the glass slip ; place a mi- 

 nute portion of the glycerin — the proper quantity for different 

 sized covers being soon found under a little practice — in the 

 centre of this ring with a rubber bulb " dropper " to avoid 

 bubbles ; insert the object in this glycerin by means of needles ; 

 lower the cover glass upon the object very slowly ; avoid 

 squeezing out the glycerin beyond the cover, using only deli- 

 cate pressure with the needles, sufficient to cause the fluid to 

 spread to the entire periphery of the cover ; seal the mount at 

 once with a solution of brown shellac in alcohol, used as thick 

 as will flow easily, which shellac will form a jelly by union with 

 the glycerin at the edge of the cover, thus preventing the run- 

 ning in of cement subsequently applied ; set the mount aside 

 for twelve or twenty-four hours ; and then finish with a cement 

 consisting of equal parts of Japan gold size and ordinary asphalt 

 varnish. One coat of this cement will hold for a long time, but 

 it is belter to use successive coats, laid on at intervals of twelve 

 or twenty-four hours, until a smooth, bevelled ring covers the 

 edge of the mount. 



In the use of a cell of any considerable depth, where it is not 

 so easy to avoid excess of glycerin, after the cover is gently pressed 

 down, apply a spring clip of very moderate force, only sufficient 

 to maintain its own position when the slide is handled ; wash 

 away the excess of glycerin by holding the mount slightly in- 

 clined under a gentle stream of water, about the diameter of a 

 lead pencil ; avoid drawing out the glycerin by attempting to 

 wipe the cover or its joints, but blow away the adhering water 

 with smart puffs of breath ; place the mount on the turn-table, 

 with the spring clip still in its position, and seal at once with the 

 shellac solution, and after twelve or twenty-four hours cement 

 with the black mixture as before. 



