1 6 THE POPULAR SCIENCE MONTHLY. 



What, now, should be the mechanical construction of a successful 

 flying-machine ? How should it be built ? In what way should the 

 I)o\ver be applied ? I have tried to make clear what seem to me the 

 principles involved, but the best method in which to apply them can 

 only be found by patient and intelligent study and experiment. Many 

 men have been and are now working at the problem, and that it will 

 be eventually solved seems certain. A bird's muscles, while strong, are 

 not as strong as steel, and while his power in proportion to his weight 

 is great, we can exceed it ; and let us not admit that we can not equal 

 his intelligence in applying it. 



One of our illustrations shows the flying-machine invented by Mr. 

 ileuson in England in 1842, and deserves mention as being the first 



Fig. 4.— Henson's Aerostat. 



of importance designed to fly without the aid of muscular power. 

 The chief feature was the very great expanse of its sustaining planes, 

 which were larger in proportion to the weight than in many birds. 

 The machine advanced with its front edge a little raised, and the air 

 acting upon the lower surface, when the proper speed had been at- 

 tained, was expected to lift and sustain it. This speed at the start-off 

 was to be got by running down an inclined plane or hill, and the ob- 

 ject of the screw-propeller was simply to keep up the motion. It is un- 

 necessary to say that this machine did not work, and yet Ilenson 

 evidently had a glimmering of what is required. He introduces the 

 inclined plane and propeller, but does not apply them in a practical 

 way. Such a machine, of course, would be completely at the mercy 

 of the winds ; and while he might find a convenient hill to roll down 

 in order to get the required velocity, in coming to earth again there 

 might be trouble. 



Lnndell's flying-machine, invented in 18G3, was also provided with 

 an extensive aero-plane, but differs in having screws acting vertically 

 to sustain the machine in addition to those for driving it forward. 

 Capping all are two parachutes, intended to open and prevent a sudden 

 fall in case of accident. There are four sets of blades on each ver- 

 tical screw-shaft, on the principle, one would think, that if one set 

 would be a good thing, four sets would be four times as good. They 



