1872.] Natural and Artificial Flight. 203 
was attacked in a manner and with an energy which left 
little doubt in my mind that it played quite a subordinate 
part in the great problem before me. The necks of the 
birds were stretched out, and their bodies to a great extent 
rigid. They advanced with a steady stately motion, and 
swept past with a vigour and force which greatly impressed, 
and to a certain extent overawed, me at the time.* Their 
flight was what one could imagine that of a flying machine 
constructed in accordance with natural laws would be.” 
So much for Natural Flight ; and now for a few words on 
Artificial Flight. 
“* How to Construct an Artificial Wing on the Insect Type.— 
The following appear to me to be essential features in the 
construction of an artificial wing :-— 
The wing should be of a generally triangular shape. 
It should taper from the root towards the tip, and from 
the anterior margin in the direction of the posterior margin. 
It should be convex above and concave below, and slightly 
twisted upon itself. 
It should be flexible and elastic throughout, and should 
twist and untwist during its vibration, to produce figure-of-8 
curves along its margins and throughout its substance. 
Such a wing is represented at Fig. 15, and as it is forced 
into undulations when it is made to vibrate, I propose to 
designate it the wave wing. 
If the wing is in more than one piece, joints and springs 
require to be added to the body of the pinion. 
In making a wing in one piece on the model of the insect 
wing, such as that shown at Fig. 15, I employ one or more 
tapering elastic reeds, which arch from above downwards 
(a b) for the anterior margin. To this I add tapering elastic 
reeds, which radiate towards the tip of the wing, and which 
also arch from above downwards (g, , 7). These are so 
arranged with reference to the anterior margin of the wing, 
that they confer a certain amount of spirality upon the wing as 
a whole. The anterior (a 6) and posterior (c d) margins are 
disposed in different planes, and appear to cross each other. 
I then add the covering of the wing, which may consist of 
india-rubber, silk, tracing cloth, linen, or any similar 
substance. 
The artificial wave wing just described is endowed with 
the very remarkable property that it will fly in any direction, 
demonstrating more or less clearly that flight is essentially 
* The above observation was made at Carlow-on-the-Barrow, in October, 
1867, and the account of it is abstracted from my note-book. 
