THE YOUNG SCIENTIST. 
9 
streets and stores of New York aud elsewhere for a 
dollar. 
Wishing to see how much could be done with 
such a microscope, we made one a few days ago, 
and tested it. We found that we could see dis- 
tinctly a great many of the interesting objects 
about which we read in the books, and although 
we would not advise any of our readers to depend 
upon such a microscope for work or study, yet, as 
it would be a good exercise to make and test one, 
we will give the way in which we made ours. 
We picked out a piece of thin window glass, quite 
flat and free from specks and air-bubbles. The 
sharp edges were removed by means of an old file, 
and the glass carefully washed with washing soda 
and water, no soap being used. We then took some 
Canada balsam, or balsam of fir as it is called, and 
boiled it hard on a second slip of glass. The heat 
must be moderate, and all bubbles and specks must 
be removed by means of a pin point. A single 
bubble in the lens will spoil it. A drop of this 
clear balsam, made liquid by heat, was placed on 
the first slip and made as nearly circular as possi- 
ble. The slip was then laid flat and face down- 
wards to cool and harden, being supported by a 
small box to keep the balsam free from dust and 
from contact with anything. The lens was now 
made. Its action was greatly improved, however, 
by placing a thin blackened card with a small hole 
between it and the eye. 
A holder for such a lens may be made in a few 
minutes, with a pocket knife. Ours is shown in the 
engraving. The handle is simply a piece of wood, 
Fig. 1. 
round, and with two saw cuts in the top, in which 
the glass slip, A, and the card, D, are stuck. To 
hold the object, we made the stage, shown in Fig. 2, 
and which is carried by a wire, F, stuck in the han- 
dle. The stage is a piece of wood, with a small hole, 
F, by which it slides on the wire, and another 
larger hole, H, to allow the light to pass through 
the object. Eubber bands, R R, serve to keep in 
place the glass sUp, B, carrying the object. As 
similar letters refer to like parts in both figures, it 
will be easy to understand the disposition of the 
several parts. 
After having made it, we went through our cab- 
inet to see what we could do. Finding a piece of 
trichinous pork, we, with a sharp razor, shaved off 
a very thin slice (not thicker than tissue paper), 
which we moistened with glycerine and laid on the 
Fig. 2. 
glass slip, covering it with a thin scale of mica, 
(used for stoves, and sometimes called isinglass). 
We had plenty of thin glass, but wished to use only 
such things as could be found in any country vil- 
lage. We saw the trichina, or pork worms, beauti- 
fully. There they lay coiled up in their cysts, or 
bags, and any one might, by the aid of such an ex- 
temporized microscope, have told whether this 
sample of pork was dangerous or not. 
We then took a speck of sour paste, and after 
mixing it with a little water, placed it on the glass 
slip, strewed a few short pieces of hair (cut from 
our own head) amongst it, covered it with mica 
and examined it. The object of the hairs was to 
prevent the mica from crushing the eels, and when 
we have not the regular appliances they should 
always be used in the examination of animalcules. 
Seen by our penny microscope, the eels appeared 
very large and distinct, with their internal organs 
clearly seen through their transparent skins. 
The most beautiful object, however, was the so- 
called globe animalcule {volvox glohaior). This ob- 
ject can be readily found in most localities in ponds 
of clear, still water. We have found it in New Jer- 
sey during every month in the year. It is too ex- 
quisitely beautiful to be described, and our readers 
should search for it until they find it. 
The magnifying power of the microscope we used 
was about twenty diameters. Great confusion of 
ideas prevails in the popular mind in regard to 
magnifying power, aud this confusion has been 
increased by street opticians, who claim " a thou- 
sand times" for microscopes which do not magnify 
as much as the one we have just described. This 
has produced a reaction the other way, and we have 
