42 
THE YOUNG SCIENTIST. 
We have performed this experiment upon 
every scale, using in some cases a small ten 
cent magnet, and in others a row of a dozen 
electro-magnets— the poles being wide apart, 
and the current quite strong. The magnets — 
were all firmly fixed to the same bar of wood, 
which was considerably elevated. When this 
bar was struck lightly with a hammer, a perfect 
sheet of burning iron fell down, and the effect 
was almost indescribable. 
Oh! my!! 
What Power Shall we Use? 
It is a very common error to suppose that in 
order to see anything clearly it is necessary to mag- 
nify it very much. Some things undoubtedly re- 
quire very great magnifying power, bub the major- 
ity of objects that are examined or studied by 
young microscopists are best seen with a moderate 
power. We must remember that when a very great 
magnifying power is applied to ordinary objects, 
we are able to see only a very small portion of 
them; no clear idea can be formed of the relation 
of the different parts, and the result is very unsat- 
isfactory. At least 90 per cent of all the most 
interesting objects that are likely to present them- 
selves to young microscopists can be seen very well 
by means of powers under two hundred diameters, 
and the range of objects that can be seen with a 
power of less than one hundred diameters is very 
large. Let us enumerate a few. 
Almost all the opaque objects which are so cele- 
brated for their beauty, can be seen with a power 
of twenty-five diameters. The Ust includes min- 
erals, seeds, butterfly's scales, and other prepara- 
tions of plants and insects. The general structure 
of plants, as shown by sections of stems, leaves, 
etc., is also well worth examination by this power. 
It will also show the general appearance of the 
larger animalcules, and of very many of the smaller 
larvae of insects, as found in water. 
A power of fifty diameters may be applied with 
good results to many of the objects just named. 
Such a power shows well such objects as the eels 
in paste, trichina in pork, the Yolmx Globator, and 
many of the larger desmids and diatoms. The 
crystals of different salts, and particularly the 
active process of crystalization, are best seen under 
this power. The deposition of crystals of pure sil- 
ver, obtained by decomposing a salt of that metal, 
is one of the most magnificent sights known to 
microchemistry. 
With a power of 100 diameters, we can see the 
more minute structures of many of the objects 
named. Thus the eels in paste are seen not only 
as a whole, but their internal organs can be dis- 
j tinguished. We can also see the form of the blood 
corpuscles, and distinguish between the blood of 
the frog, the chicken and man. Some of the most 
wonderful sights can also be seen with this power, 
such as the circulation of the blood in the foot of 
the living frog. In short a description of the ob- 
jects which may be profitably examined under this 
power would fill a large volume. 
Paste-Eels. 
Since the mention of these in our first number, 
we have had numerous inquiries in regard to the 
best means of obtaining them. It is generally said 
that if well-boiled paste is allowed to stand for some 
time, until it becomes sour, it will swarm with 
them. Such has not been our experience. During 
the summer we have kept paste until it attained 
every stage of decay, but no eels made their ap- 
pearance, and we doubt very much if eels ever ap- 
peared in paste that had been well boiled, and had 
not been mixed with unboiled water. We have not 
been able to obtain them, except by the transfer of 
material known to contain them or their ova. 
These seems to be present in some samples of 
water, and when placed in paste they multiply with 
astonishing rapidity. 
Paste eels are a very curious object under th-e 
microscope — indeed there are few objects that are 
more interesting to young people and beginners. 
They are easily raised and kept. Make a little well- 
boiled paste, and allow it to stand until sour. Add 
some old paste, containing eels, and in a short time 
the entire mass will be alive with them. 
Our readers will doubtless ask, " Where shall we 
get the old paste ?" We have plenty of it. Either 
call on us, or send a three-cent stamp, and we will 
