THE YOUNG SCIENTIST. 
77 
the standard, and up to the other end of the 
bender, drawing it tight, so as to spring the 
Fig. 12. 
bender to a bow shape, just as you see in 
Fig. 13. Now you see that one side is bent 
more than the other, the side A being the 
least bent. Now, let us see if that isn't the 
side that was a little the heaviest when we 
balanced the bender. Yes, it is; I thought 
so., Now we will take a piece of sandpaper 
and reduce that side a little, and that will 
Fig. 13. 
make the bend and the weight both right. 
If you want to see how much it is out of 
true, Just look at the distance between the 
dotted lines and the bender on each side. 
Our sandpapering you see has made it just 
jight." 
^^But suppose the bender had been ex- 
actly balanced, and then didn't bend right, 
Uncle?" 
"I am just coming to that, Harry. You 
see that, in Fig. 13, one side of the bender 
is marked A, and the other B, while the 
string bending it is marked C on one side 
and D on the other. Now the lengths of 0 
and D must be just equal, and we make 
them equal by slipping the twine in the 
notch, which, you remember, we made in 
the end of the standard, that is at E. When 
we have made them equal, we tie the twine 
tightly to the standard near the end E, 
using another piece of twine, and letting its 
ends hang down in a loop to tie the tail to. 
Next we take a piece of twine and tie it to 
one end of the bender, drawing it just tight, 
but not enough to bend the bender, and 
fastening it to the standard, where it meets 
the bender — that is, it will occupy the 
position of one of the dotted lines in Fig. 
13. We next fasten another piece the same 
way on the other side, and then, instead of 
the dotted lines, we shall have pieces of 
twine. If one side of the bender wants a 
little more bending, we must draw the piece 
of twine last added a little tighter, and if 
this slackens one of the lines C or D, we 
must tighten the latter again. We next 
take another piece of twine and tie it to one 
end of the bender, draw it just tight enough 
to feel the strain, and pass it straight across 
to the standard, tying it there; then pass it 
straight across to the other end of the 
bender, draw it just taut, and tie it there; 
and then our frame is made." 
"Is there any way of testing if it is the 
right shape and evenly balanced?" 
"Yes; here is our kite frame (Fig. 14) all 
finished, and if you measure and compare 
the length of A on one side with that of A 
on the other, you will find them equal, and 
so it is with the lines B on each side, and 
the lines 0 — all are of equal lengths, while 
C on each side is an equal distance from the 
curve of the bender. This proves that the 
frame is even shaped, and so there is as 
much surface, for the wind to strike against, 
on one side of the kite as there is on the 
other. Now for the balance; all we can do 
