jranchcster Memoirs, Vo/. xliv. (1900), No. II. 13 



of the aeronaut to descend upon any point of the earth 

 can only be exercised witliin wide areas, while the 

 conditions of safety are wholly absent in general practice, 

 as the numerous fatalities recorded unhappily testify. 



^^^. I have already indicated (27) some of the diffi- 

 culties to be encountered in the construction and working' 

 of aviating machines the sustaining power of which is 

 derived from aerial screws. Even if these difficulties were 

 ultimately overcome, there would still remain the element 

 of danger arising from the accidental failure of the rotating 

 mechanism. The magnitude of this danger, with its con- 

 sequences, as I have said, is hardly realised or is altogether 

 ignored by aeronautical projectors. Those who have had 

 much experience with moving mechanism, with its liability 

 to derangement from various causes, will feel that the 

 penalty involved for human error and want of foresight is 

 too severe to warrant the belief that the sublime consum- 

 mation of successful aerial locomotion will be brought 

 about by a machine deriving its support from aerial 

 screws. 



34. The like observation in regard to the absence of a 

 principle of safety also applies to the various frying 

 machines projected, which derive their support in the air 

 from flapping wings actuated by a steam-engine or other 

 motor. 



35. Much attention has been given by aviators during 

 recent }'ears to the means by which the soaring of birds is 

 accomplished, with a view to adapting the principle to the 

 production of a soaring aerial machine. In the experi- 

 ments which have hitherto been made with this object, 

 stationary aeroplanes inclined upwards in the direction of 

 motion derive their ascensional power from their rapid 

 motion horizontalh' through the air, the driving power 



