THE YOUNG SCIENTIST. 
jaws, as shown, then work it off some- 
thing like the shape shown in Fig. 5. This 
handle may be fastened to the jaw by a 
small screw or a little wedge or key, which 
Fig. 5. 
may fit into a slot left in the handle, as 
shown. 
On the saw ends of the jaws it is desir- 
able to have ferrules made of tin, copper, 
or brass, nicely fitted on, as they prevent 
them from splitting when the clamps are 
screwed in. These ferrules, or thimbles, 
can be obtained in any hardware store ; if 
not, a couple of common thimbles, filed 
down and nicely fitted on, make excellent 
substitutes. 
Eor a clamp to hold the saw, we know 
of nothing in the market so cheap and 
efficient as the one shown in Pig. 6, which 
can be obtained from most hardware 
stores for about twenty or twenty-five 
cents a pair. The shank on each one is 
Tig. 6. 
from one and three-quarters to two inches 
in length, and has a thread cut on one end 
for about an inch in length, the other end 
having a thumb-nut and screw, as shown. 
Great care must be taken to get these 
clamps in straight and true, and to pre- 
vent the ends of the jaws from splitting. 
When the clamps are in place, the 
handle on, the saw made fast, and the 
cord tightened up, the work is nearly com- 
pleted ; all that is then to be done is to 
sandpaper the whole work, and give it 
two or three coats of raw linseed oil, rub 
in, then wipe off surplus oil with a clean 
cloth, and you will have a saw complete in 
every particular, for the small sum of 
forty cents. You will also have received a 
lesson in practical mechanics that is worth 
more to any boy than the value of a dozen 
saw frames. 
67 
Drawing Lessons— II. 
BY JOHN CLARK CENTER. 
NOW that you understand the difference 
between perpendicular, horizontal, 
and oblique lines, let us turn our atten- 
tion to angles and their peculiar relations 
to some standard of measurement. 
Eight angles are easily recognized when 
we have to deal with perpendicular and 
horizontal lines; but if they should be 
Fig. 1. 
placed in an oblique position their charac- 
ter is not so obvious. A right angle is con- 
tained between any two lines proceeding 
from the centre of a circle, which include 
one-fourth part of the circumference or 
ninety degrees. If even a single degree less 
than this it becomes an acute angle, and if 
larger than ninety degrees it is an ob- 
tuse angle. To impress on the mind the 
Fig. 2. 
appearances of these angles in different 
positions, the student should devote some 
time to drawing them and studying their 
relations. 
A square is a figure circumscribed by 
