THE LANGLEY AERODROME. 



213 



and which will enable it to move of its own volition, as it were, in a 

 horizontal course. 



Now the reader may be prepared to look at the apparatus which 

 tinally has flown. (See diagram.) In the completed form w^e see two 

 pairs of wnngs. each slightly curved, each attached to a long steel rod 

 which supports them both, and from which depends the body of the 

 machine, in which are the boilers, the engines, the machinery, and the 

 propeller wheels, these latter being not in the position of those of an 

 ocean steamer, but more nearly' amidships. They are made sometimes 

 of wood, sometimes of steel and canvas, and are between 3 and -Jt feet 

 in diameter. 



The hull itself is formed of steel tubing. The front portion is closed 

 by a sheathing of metal which hides from view the fire grate and appa- 

 ratus for heating, but allows us to see !i little of the coils of the boiler 



Diagram of the aerodronu'. 



and all of the relatively large smokestack in which it ends. The coni- 

 cal vessel in front is an empty float, whose use is to keep the whole 

 from sinking if it should fall in the water. 



This boiler supplies steam for an engine of between 1 and li horse- 

 power, and, with its fire grate, weighs a little over 5 pounds. This 

 weight is exclusive of that of the engine, which weighs, with all its 

 moving parts, but 26 ounces. Its duty is to drive the propeller 

 wheels, which it does at rates varying from 800 to 1,200, or even more, 

 turns a minute, the highest number being reached when the whole is 

 speeding freely ahead. 



The rudder, it will be noticed, is of a shape very unlike that of a ship, 

 for it is adapted both for vertical and horizontal steering. It is impos- 

 sible within the limits of such an article as this, however, to give an 

 SM 1000 15 



