THE YOUNG SCIENTIST. 
107 
He is too high for the trout, and so there 
is surely no danger. Perhaps it is the 
music of his wings, or more likely the 
the shadow of his body on the water below, 
that attracts the attention of the little 
archer-fish, as he roves around among the 
weeds and pebbles of the pond. 
Inspired by the prospect of a hearty 
meal, this water huntsman arms himself 
and is off. Slowly he! approaches the sur- 
face, so directing his course that when his 
nose rises above the water, it shall be at 
that point nearest to the game he seeks. 
No sooner is the surface reached than away 
goes a little crystal bullet — a drop of water 
— and down comes the fly. So sure was 
his aim, and so powerful the force of 
the blow, that, though often three feet dis- 
tant, and on the wing, the game is secured 
and borne down to the home among the 
pebbles. 
The little fish which has so proved his 
skill as a marksman, is seldom over six 
inches in length, and is know to naturalists 
by the name Texotes jaculator. It is found 
in some of the fresh-water lakes of J apan. 
It is easily domesticated, and when secured 
in the aquarium, is active in the practice of 
its art, and seldom fails to capture or bring 
down the game at which it shoots its crystal 
bullets. 
To Pkevent " Day Dreaming. " — Study 
mathematics; engage in solving problems; 
bring your mind down to matters of fact; 
read works on natural history, on the natu- 
ral sciences; give up romance, novels, etc. ; 
try your hand at mechanism; invent and 
use machinery; finish what you begin, and 
you will cultivate application and prevent 
the mind from wandering. 
Canada Balsam Microscopes. 
ri1HE article on penny microscopes in the 
first number of this journal was quite 
interesting to me, recalling to mind the 
balsam lenses I have made in times past. 
Of course these cheap lenses can not be 
used for scientific purposes, nor their per- 
formance be depended on for accurate 
work, nevertheless they may be made very 
instructive and entertaining, and with a 
good book, such as Kev. Wood's "Common 
Objects of the Microscope," or Lankester's 
"Half Hours with the Microscope," almost 
any person can learn enough to pay for the 
trouble of making the microscope and the 
money expended for the book. 
About two years ago — it was before the 
summer of 1876 — I made and experimented 
with some of these balsam lenses. I found 
it difficult to make a lower power than 
twenty diameters, with good definition, but 
the higher powers were much more easily 
made and gave far better results, but they 
had a ve^ry short working distance and were 
hard to use on that account. I used a pill 
box with a hole in both bottom and cover. 
Over the bottom (outside) was a thin piece 
of mica; on this mica, inside of the box, 
was a very small drop of balsam. For a 
diaphragm I used a piece of black tissue 
paper with a pin hole in it; this was 
gummed on the outside of the mica — the 
hole coming under the lens — and the edges 
turned down around the box, which was 
then covered with gilt paper. It then pre- 
sented a very neat appearance. 
The highest power I ever made, was 
three hundred diameters, and it had work- 
ing distance enough to use No. 1 covers. I 
used to take considerable pleasure in *' fight- 
ing " these balsam microscopes against 
cheap non-achromatic compound micro- 
scopes, such as Queen's and McAllister's 
" Household " etc. The balsam lenses would 
usually beat! 
This morning I came across a box con- 
taining four of these balsam microscopes, 
among them was the one magnifying three 
hundred diameters. I took a slide of 
Stauroneis Phoenicenteron from my cabinet, 
and was surprised to see how plainly I 
could see them. I got a glimpse of the 
lines but they did not show very plainly 
until I moved my hand so that sunlight 
could strike them, when, to my surprise, I 
