THE YOUNG SCIENTIST. 
97 
upon its readers the wide range of experi- 
ments which may be performed with yery 
simple means : " It is true that almost all 
the more important facts and laws of the 
physical sciences can be illustrated and 
explained by the help of experiments 
made without special or expensive ap- 
paratus, and requiring only the familiar 
objects of common life for their perfor- 
mance. The greatest exponents of popu- 
lar science— and amongst them notably 
Faraday— delighted in impromptu devices 
of this kind. It is indeed surprising how, 
throughout the whole range of natural 
philosophy, the hand of the master can 
turn to account the very simplest and 
rudest of apparatus. A silver spoon, a 
pair of spectacle lenses, a tumbler of 
water, and a few sheets of jmper suffice to 
illustrate half the laws of geometrical 
optics. A few pieces of sealing-wax, some 
flannel, silk, writing paper, pins, and 
glass tumblers will carry the clever ex- 
perimenter a long way into the phe- 
"nomena of electricity. These are things 
which any person can procure, and which 
any person can be taught to use. But 
their right use depends on the possession 
of accurate scientific knowledge, and a 
clear understanding of what the various 
experiments are to prove." To all which 
we say— Amen ! 
The first illustration which Ave take 
from La Nature is an old experiment 
tolerably familiar to the boys of half a 
century ago. The author of the article on 
" Ph3^sics Without Apparatus," gives it 
simply as an illustration of a lever, which 
it certainly is not. The old problem was : 
" Can you lift a bottle with a straw with- 
out tying the straw to the bottle ? ' ' The 
uninitiated were always obliged to give it 
up, but those who were familiar with the 
trick carefully selected a sound straw, free 
from bends or bruises, and then t^fter 
bending it as shown in the figure, intro- 
duced it into the bottle or decanter. 
Then, on taking hold of the upper end of 
the straw, the bottle was easily raised. 
On examination we find that the straw is 
here pulled at one point and compressed 
at another. A straw subjected to a pull- 
ing strain will lift much more than the 
weight of a decanter, but if used as a lever 
it will bend and break with a tithe of that 
weight. The other part of the straw is in 
a state of compression. When we pull on 
the long or upper part it is prevented 
from coming out because the bend cannot 
slip up without shortening or compress- 
ing the other part of the straw. If the 
straw is strong enough to resist this the 
decanter will be held. 
It certainly cannot be said that the 
straw is here used as a "lever." The 
principle by which we are enabled to lift 
the decanter is that a sound straw is able 
to resist a very considerable force when 
the latter is applied directly, either to ex- 
tend or to compress it. 
It will be found that it is much more 
important that the straw be perfect be- 
tween the angle and the lower end, than 
between the angle and the upper end. 
Indeed, the slightest bruise or imperfec- 
tion in this part will allow it to bend, and 
then it will be drawn out of the decanter. 
As an illustration of the nature and di- 
rection of strains, and the ability of ma- 
terials to resist them, this experiment is 
very instructive. 
The American Institute. 
THE Fair of the American Institute 
promises to present unusual attrac- 
tions this year. Amongst other new fea- 
tures, is the admission of the work of 
amateurs and apprentices free of charge. 
Amongst the judges in this department 
are some prominent ladies. So long as 
the Institute seeks by all legitimate means 
to foster education and the improvement 
of the young in industrial and artistic 
pursuits, just so long will it retain a firm 
hold upon the hearts of the i)eople and 
secure that permanent success which can 
come only to earnest and worthy efforts. 
One of Our Pond-Dwellers. 
THOSE who take pleasure in examining 
the living creatures which find a home 
in our ponds and rivers, must often have 
come across the beautiful rotifer, of which 
we give an engraving. It is a conspicuous 
object, easily seen and examined under 
ordinary microscopes. 
Figure 1 shows the Noteus qtiadricornis 
