216 



AERONAUTICS. 



elude my present communication by describing an instrument 

 of this kind, which any one can construct at the expense of 

 ten minutes' labour. 



" a and h (fig. 1 1 1, p. 215) are two corks, into each of which 

 are inserted four wing feathers from any bird, so as to be slightly 

 inclined like the sails of a windmill, but in opposite directions 

 in each set. A round shaft is fixed in the cork (X, which ends 

 in a sharp point. At the upper part of the cork J is fixed a 

 whalebone bow, having a small pivot hole in its centre to 

 receive the point of the shaft. The bow is 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 finger on the upper cork press strong enough to 

 prevent the string from unwinding, and, taking it away sud- 

 denly, the instrument will rise to the ceiling.'' 



Cayley's screws were peculiar, inasmuch as they were super- 

 imposed and rotated in opposite directions. He estimated 

 that if the area of the screws was increased to 200 square 

 feet, and moved by a man, they would elevate him. Cayley's 

 interesting experiment is described at length, and the ap- 

 paratus figured in Nicholson's Journal for 1809, p. 172. In 

 1842 Mr. Phillips also succeeded in elevating a model by 

 means of revolving fans. Mr. Phillips's model was made 

 entirely of metal, and when complete and charged weighed 

 2 lbs. It consisted of a boiler or steam generator and four 

 fans supported between eight arms. The fans were inclined 

 to the horizon at an angle of 20^, and through the arms the 

 steam rushed on the principle discovered by Hero of Alexan- 

 dria. By the escape of steam from the arms, the fans were 

 made to revolve with immense energy, so much so that the 

 model rose to a great altitude, and flew across two fields 

 before it alighted. The motive power employed in the pre- 

 sent instance was obtained from the combustion of charcoal, 

 nitre, and gypsum, as used in the original fire annihilator ; 

 the products of combustion mixing with water in the boiler, 

 and forming gas charged steam, which was delivered at a 

 high pressure from the extremities of the eight arms. This 



