THE MICROSCOPE. 



ovals, — are to be placed upon each end, when the appearance of 

 the whole mount will be extremely neat and handsome, and the 

 maker's mind need bear no troubles as to its future. Should any 

 appearance of moisture under the cover be seen (which is not at all 

 likely), a slight warming over the lamp will dispel the same, and 

 leave all in pristine brightness. 



Should our specimen be too bulky or thick to be contained 

 within the shallow depths of a cell made of the thinnest blotting 

 pad, we must have recourse to the wooden slips, which will be found 

 to form a cell deep enough for any mounting one may ever desire 

 to make. The method of so doing is precisely the same as that fol- 

 lowed with the glass slip, excepting that we must paste a strip of 

 cardboard, covered with the dead black paper, to the under side of 

 the slip to form the bottom of the cell. The slide is to be covered 

 with the papers, and labeled exactly the same as though it were of 

 glass. 



Should the black paper not be readily procurable, a very excel- 

 lent dead black for the bottom of the cell may be made with com- 

 mon lampblack water color, which dries with a dead surface very 

 agreeable and pleasant for mounting foraminifera and similar objects 

 upon. If a little gum arable be mixed with the water, and the 

 specimen placed upon the surface of the paint whilst still moist, it 

 will be found that the latter will form an excellent cement, as well 

 as background for holding the preparation. 



Illumination by means of a lieberkuhn, which throws the light 

 directly down upon the object without shadows, has been too much 

 neglected. In England it is a very ordinary method of viewing the 

 opaque objects, and a lieberkuhn is usually furnished with every ob- 

 ject-glass from a three inch to a four-tenths. But it is different 

 here, and I am quite sure that the great majority of our observers, 

 professional and amateur, are totally unacquainted with its use. I 

 think this is to be regretted, since they lose much, both in pleasure 

 and instruction from its non-employment. Hoping that its use may 

 become more general, I will give a hint or two as to the method of 

 mounting a preparation, to be examined by this form of illumina- 

 tion. 



The lieberkuhn is a concave speculum fitting over the mounting 

 of the objective so that the front lens of the latter project through 

 the middle of the lieberkuhn. Parallel rays of light are thrown up- 



