328 MANAGEABLE AIR -SHIPS. 



animals, if only the fundamental condition be fulfilled, 

 which consists in this, that we have machines as light 

 and powerful as the motor muscles of flying animals 

 and which do not require a much larger supply of 

 combustible material. When such a machine is invented, 

 every skilled mechanician can make a fly ing -machine. 

 The inventors however always begin at the wrong end, 

 and invent flying mechanisms without having the power 

 for moving them. Still worse is it with the manageable 

 air-ships. The problem of their construction has been 

 long ago solved in principle, for every air-balloon may, 

 in perfectly calm weather, be slowly propelled in any 

 direction by a suitable mechanism applied in the car. 

 Progress however can only be slow, because in the 

 first place power -machines of sufficient lightness are 

 still wanting to drive the voluminous balloon at greater 

 speed through the air or against the wind, and secondly 

 because the material of the balloon would not stand a 

 strong counter -pressure of the atmosphere, even if we 

 possessed such machines. The oblong form, which the 

 inventors give the balloon, in order that it may better 

 cleave the air, increases its weight with equal volume 

 and is therefore worthless. The like holds good of the 

 application of inclined planes, which are intended to 

 facilitate the supporting of the weight. 



Besides these two problems there are a number 

 of others on which inventors squander time and money 

 by failing to perceive that the means for carrying 

 them out are not yet at the disposal of applied science. 



