ON THE TEOGEESS OF AEEONAUTICS. 
373 
u Though we are still without a precise demonstration of 
the power required for flight in the way that a bird flies, the 
force to maintain which, in some species, must he very small, 
yet we have some evidence of the power required to lift a 
weight in the air by means of vertical screws. By this 
method it has been demonstrated that 100 pounds may be 
supported by a constant force of about 90,000 foot-pounds, or 
three horse-power. 
“ Now, in the work of Mr. Stringfellow, the society has 
brought out the remarkable fact that a one-horse power 
engine can be made to weigh only 13 lbs., thus showing the 
possibility of obtaining flight by the repudiated system of 
vertical screws, even with the enormous expenditure of power 
that this plan is known to require.” 
In order to ascertain what actual lifting power could be 
obtained with planes moving in horizontal orbits, Mr. Moy 
constructed new aero-plane wheels, 12 feet in diameter, with 
twelve planes to each wheel, the whole presenting 160 square 
feet of surface, driven by a steam-engine weighing 80 lbs. By 
placing the whole acting surface on these two wheels, an in- 
teresting experiment was carried out. 
It was palpable, however, that from the conditions of the 
actual trial the full lifting-power due to the surface, angle, and 
velocity could not be hoped for. These revolving planes were 
travelling all the time in one circle. They had not the advantage 
of obtaining an abutment upon a previously undisturbed body 
of air. The experiment was in an enclosed part of the build- 
ing. Great part of its power was expended in drawing down- 
wards a body of air. The whole weight of the machine was 
186 lbs. Levers were attached to the spindle of the aero- 
plane wheels, which were weighted to take off all over 120 lbs. 
This latter weight was raised from the floor — according to the 
independent testimony of Captain Greenfield, of the Boyal 
Artillery — as much as six inches under one aero-plane, and two 
inches under the other, this inequality being due to one wing- 
plane having broken. 
The engine, therefore, was proved capable of raising itself, 
and 40 lbs. additional weight, under great disadvantages. The 
revolutions of these two 12-feet aero-planes were sixty-seven 
per minute. 
The preparations for the experiments, which have here so 
easily been summed up, occupied winters and summers. Re- 
peated breakages, renewals, strengthenings, re-construction, re- 
adjustment, both in engine and apparatus, testify to the 
patient perseverance of the inventor, and those associated with 
him. And though lastly mentioned, yet by no means the least, 
was the constant leakage of the not too auriferous money- 
bag. 
