158 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



when he was approaching the solution of the problem, in fact, had 

 attained it, is one of the tragedies of science, and a painful reminder 

 of the gap that still exists between the true scientist and the mass of 

 the community, even in highly civilized lands. 



It would, however, be inaccurate to claim for Langley absolute 

 priority for the idea that a heavier-than-air machine can be made to 

 fly. To think of an invention is a simple mental effort, and there are 

 few of the great inventions or discoveries of the modern time that 

 can not be found foreshadowed in the records of the past. A Greek 

 poet describes in set terms the invention of submarine warfare, when 

 Scyllus and his daughter, expert swimmers, dived at the sides of 

 Xerxes' ships, cut the mooring cables, and thus caused many ships 

 to drift to their destruction. 



About the time of the discovery of America that remarkable and 

 versatile genius, Leonardo Da Vinci, wrote an essay on the flight of 

 birds, and referred to the possibility of human flight. I have not 

 been able to consult the original essay, but notes thereon, by Da Vinci, 

 have been translated, 1 and from this text I make a few selections : 



I have divided the Treatise on Birds into four books: of which the first treats 

 of their flight by beating their wings; the second of flight without beating the 

 wings, and witli the help of the wind ; the third of flight in general, such as 

 that of birds, bats, fishes, animals, and insects ; the last of the mechanism of this 

 movement. * * * 



Remember that your bird should have no other model than that of the bat, 

 because its membranes serve as armor, or rather as a means of binding to- 

 gether the pieces of its armor, that is the framework of the wings. * * * 

 The bat is aided by the membrane which binds the whole together, and is not 

 penetrated by the air. 



Dissect the bat, study it carefully, and on this model construct the machine. 



The bird I have described ought to be able by the help of the wind to rise to a 

 great height, and this will prove to be its safety ; since even if all the above- 

 mentioned revolutions were to befall it, it would still have time to regain its 

 equilibrium ; provided that its various parts have a great power of resistance, 

 so that they can safely withstand the fury and violence of the descent, by the 

 aid of the defences which I have mentioned ; and the joints should be made 

 of strong tanned hide, and sewn with cords of very strong raw silk. And let no 

 one encumber himself with iron bands, for these are soon broken at the joints, 

 or else they become worn out, and consequently it is well not to encumber one's 

 self with them. 



It will be seen from these quotations that Da Vinci's plan w 7 as to 

 equip a man with wings to be operated by his muscles, probably 

 those of both legs and arms, for in another note he states that the 

 muscles of the legs are much more powerful than the ordinary work 

 done by them requires. He did not contemplate the use of machinery. 

 It must be borne in mind that in that day, no powerful, portable 

 prime mover was known. 



1 Leonardo Da Vinci's Note Books. Translated by Edward MeOurdy, A. M. London, 

 Duckworth & Co.. 190G. 



