MOUNTING OF MICROSCOPIC OBJECTS. 2J 



lac, turned upon a whirling table with the point of a pen-knife, at 

 an immense expenditure of time and patience; others of wax, bone, 

 tin, hard and soft rubber, curtain rings, and a host of other sub- 

 stances; anything, in fact, but those, or rather that possessing the 

 one quality needful for a dry cell, namely, the quality of remaining 

 dry. For be it distinctly understood, that though a 

 cell may be made and hermetically sealed, in which 

 no appearance of moisture will ever occur, such an 

 event is an anomaly and can never be duplicated 

 with any certainty. No matter how dry the specimen may appear 

 to be, nor the atmosphere of the room or the surface of the covering 

 glass, sooner or later the under side of latter will become covered by 

 a mist like substance, which obscures and spoils the view of the im- 

 prisoned specimen. This of course is the case only with such pre- 

 parations, as are mounted on the bottom of a cell of any depth, 

 the cover being used merely as a protection from dust and other in- 

 jury. Where diatoms, the scales of insects, or other minute objects 

 are mounted directly upon the under surface of the cover itself, this 

 cloudy or watery appearance is either never observed at all, or else 

 in so slight a degree as to cause no annoyance. When it does occur 

 in a cell such as is usually used, and for the preparation of which 

 the books give us so many elaborate directions, the only remedy is 

 to remove it, (broken of course,) and replace with a fresh one; the 

 latter in due time being predoomed to share a like fate. 



" Is there no remedy for this," you will ask, and I answer un- 

 hesitatingly yes, if you will sacrifice your artistic cells of wax or 

 what not, with their pretty colored rings of varnish, and be content 

 with those of humbler but far more useful qualities. Paper, from 

 which such dissimilar articles are now manufactured, as love letters 

 and car wheels, is our friend in need in this emergency. Not sized 

 or glazed or calendered, but soft, porous paper of various thick- 

 nesses, to suit our needs; a thick blotting pad being exceedingly 

 useful, for cells containing objects sufficiently thick to require such 

 a depth. If a still deeper cell than this be needed, then a slip of 

 wood, 3x1 inches, and the thickness of an ordinary glass slide, with 

 a hole bored through the middle is most useful; and here again 

 comes in our friendly paper to form the bottom, all of which will be 

 dwelt upon in due course. 



The requisites then, for our dry mounting in the manner to be 



