386 Flighty Aspirations. [June, 
The laws of Nature, fortunately for us, are unalterable, 
and as often as they have been questioned as to their 
adaptability for aerial suppport they have returned a favour- 
It may be conceded that a properly constructed plane 
surface, propelled against the air, will meet with sufficient 
resistance to enable its course to be deflected upwards at an 
incline obedient to the angle at which such plane is driven, 
and sooner or later according to velocity. 
An experiment is recorded in one of our annual reports 
which was made by M. de Louvrie. To a little carriage he 
fixed a thin plane surface, the angle of which he could alter 
at will. Placing this machine upon a level spot, he drew it 
along horizontally by means of a cord which was fastened 
to a dynamometer, and increased the speed until the 
machine left the ground, suspended by the pressure of the 
air on the plane. 
In a large machine, such as Mr. Lmfield s, where the 
balance cannot be adjusted with that facility which is 
readily attained with models launched from the hand, the 
difficulty will commence with the first tendency to rise. 
Supposing him to be unable to attain sufficient velocity with 
a new arrangement which he is constructing, his next step 
I presume would be to attach it to an engine on a railway, 
and repeat upon the largest scale the experiment just 
recorded. Now in such cases the laws of Nature are greatly 
in our favour, as proved by some experiments initiated by 
the Society to which I have the honour to aCt as Honoiary 
Secretary. It remains as a condition — hitherto unfulfilled 
—that man must attain to perfection in his appliances 
before he can evoke the utmost effeCt which is capable of 
being wrested from Nature in her passive mood. 
The experiments consisted in forcing a blast of air against 
various extents of surface presented to it at varying angles, 
in order to ascertain not only the force with which they 
would be driven back, but the weights which they would be 
able to lift by the air passing beneath the under surface of 
the various inclines. 
Like the sheet of stiff cardboard propelled by the slight 
pressure of the finger against the posterior edge, supported 
by the pressure of the air underneath, it was required to 
know what that pressure was which tended to lift or tilt it 
up, because that knowledge would enable us to ascertain 
what weight it would bear to keep it from so tilting up, and 
also what amount of pressure forward, represented by the 
finger, would be required to propel it. And this is one oi 
