• N AERIAL NAVIGATION, \~$ 



then to be strung equally on each side to the upper portion 

 of the shaft, and the little machine is completed. Wind 

 up the string by turning the flyers different ways, so that 

 the spring of the bow may unwind them with their anterior 

 edges ascending; then place the cork with the bow attached 

 to it upon a table, and with a ringer on the upper cork press 

 strong enough to prevent the string from unwinding, and 

 taking it away suddenly, the instrument will rise to the 

 ceiling. This was the first experiment I made upon this 

 subject in the year 17D6. If h» lieu of these small feathers 

 large planes, containing together 200 square feet, were si- 

 milarly placed, or in any other more convenient position, 

 and were turned by a man, or first mover of adequate 

 power, a similar effect would be the consequence, and for 

 the mere purpose of ascent this is perhaps the best appara- 

 tus; but speed is the great object of this invention, and this 

 requires a different structure. 



P. S. In lieu of applying the continued action of the 

 inclined plane by means of the rotative motion of flyers, 

 the same principle may be made use of by the alternate 

 motion of surfaces backward and forward ; and although Method sup- 

 the scanty description hitherto published of Mr. Degen's posed to bs 

 apparatus will scarcely justify any conclusion upon the sub- jvi/De^en." 

 ject; yet as the principle above described must be the basis 

 of every engine for aerial navigation by mechanical means, 

 I conceive, that the method adopted by him has been nearly 

 as follows. Let A and B, fig. 4, be two surface* or para- 

 chutes, supported upon the long shafts C and D, which 

 are fixed to the ends of the connecting beam E, by hinges. 

 At E, let there be a convenient seat for the aeronaut, and 

 before him a cross bar turning upon a pivot in its centre, 

 which being connected with the shafts of the parachutes by 

 the rods F and G, will enable him to work them alternately 

 backward and forward, as represented by the dotted lines. 

 If the upright shafts be elastic, or have a hinge to give way 

 a little near their tops, the weight and resistance of the pa- 

 rachutes will incline them so, as t » make a small angle with 

 the direction of their motion, and hemce the machine rises. 



A alight 



