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f 520' . Gravitation and the Soaring Birds. - [June, 
| 
; 
force developed in the fall will be enough to supply the lateral 
force and still leave fifty-eight or fifty-nine pounds to go to waste 
by falling to the tension of the surrounding air. - 
But this would not be “ soaring,” as the plane will soon reach 
the ground, = 
If we now throw the plane over on an incline of one in five, or 
18°, we have an additional twelve pounds of lateral resistance to 
overcome, which the sixty pounds is entirely competent to effect, 
together with the one or two needed to carry the plane to ¢, and 
still have forty-six or forty-seven pounds more than is wanted left 
over. We now have the plane elevated as fast as it falls, so that 
its resultant passage to D is the horizontal translation of flight, 
and a body in falling does work enough to: not only lift it to the 
same height from which it fell, but to move it against air resist- 
' ance, and have a large surplus left over! 
This seems impossible. But the reason of such appearance, aS 
already shown, is that we are entertaining a fallacy. We are 
supposing the direction of the gravitating force to still be vertical 
after it has gone over eighteen and a hundred and eight degrees. 
We have, as a matter of fact, changed the direction of gravity 
more than we have slanted the plane. One-fifth of its total 
amount has gone over 108°. The plane has taken the same lib- 
erty with the great cosmical force of gravitation that it would 
with any other force. It refuses to be operated upon by any 
energy whatever of a mechanical kind while doing work on elastic 
- fluids, excepting in the two directions mentioned, and any force 
whatever, not in either of these, is instantly put there by the 
plane. To say that the gravitating force is still vertical, and 
has not gone over, is to increase the difficulties of the °as° 
= and not to abate them. In such event the law of fluid pressures 
is violated, which demands that they be at right angles to the 
compressing surface. The plane would also fall vertically with- 
_ out lateral motion, all of which is impossible. Some force is 
-~ actuating A’ B in its own plane and normal to it. From whence 
comes it? There is but one source of supply. The plane me 
simply resolved gravity until its perpendicular line has beer 
_ vacated, and re-located at right angles to the lateral force acting 
in the plane, which lifts no weight, and resists nothing whatever 
but friction. The plané, in its translation towards <, is moving 
= towards é, but not towards e’. It is going contrary to the abstract 
. eS pee ES E ee ee 
A 
