Ma)icJicstcy Memoirs, \'ol. xliv. (1900), No. II. 11 



mc to proceed far in this direction, as, in addition to the 

 lart^e amount of power absorbed and the high velocities 

 required to produce a workable amount of thrust, an actual 

 aviating machine would of necessity require two sustain- 

 ing screws revolving in opposite directions to prevent the 

 machine from accjuiring a rapid rotator}- motion in the 

 direction of a single screw. Moreover, in addition to 

 the complicated mechanism involved in this arrangement, 

 the amount of friction created by the concentration of the 

 entire weight of the machine upon two sustaining points 

 would be very considerable and greatly diminish the 

 efficiency of the motor used for driving the screws. 



28. Although my experimental investigations cjn the 

 possibility of aerial locomotion have so far been of a nega- 

 tive character, the confidence I have in the ultimate 

 solution of the problem still remains unshaken. The fact 

 that man has been able to transport himself through the 

 air across the Irish Sea, to and from the Continent, 

 and has reached a height of nearly seven miles above the 

 surface of the earth, is sufficient encouragement to inspire 

 inventors in the field of aeronautics to further efforts till 

 the object of their ambition is attained. 



29. Notwithstanding the large amount of attention 

 that has been given to the subject of aviation since the 

 time of Leonardo da Vinci, the world is yet waiting the 

 advent of a flying machine sufficiently energetic to trans- 

 port a man from one place to another, as in ordinary 

 balloon practice. It is also to be observed that, not only 

 are most of the proposals for navigating the air mere 

 repetitions of those already known, but they manifest a 

 strange disregard of the fundamental conditions that must 

 be fulfilled before aviation can rank with man's achieve- 

 ments in locomotion on land and on water. 



