16 



ANIMAL LOCOMOTION. 



a high speed in a horizontal direction, describes a looped' 

 and then a waved track, from the fact that the figure of 

 8 is gradually opened out or unravelled as the animal 

 advances. 



That the wing acts after the manner of a kite, both during 

 the down and up strokes. 



I was induced to address the above to the French Academy 

 from finding that, nearly two years after I had published my 

 views on the figure of 8, looped and wave movements made 

 by the wing, etc., Professor E. J. Marey (College of France, 

 Paris) published a course of lectures, in which the peculiar 

 figure-of-8 movements, first described and figured by me, 

 were put forth as a new discovery. The accuracy of this 

 statement will be abundantly evident when I mention 

 that my first lecture, " On the various modes of Flight in 

 relation to Aeronautics," was published in the Proceedings 

 of the Royal Institution of Great Britain on the 2 2d of 

 March 1867, and translated into French (Revue des cours 

 scientifiques de la France et de TEtranger) on the 21st of 

 September 1867; whereas Professor Marey's first lecture, 

 '* On the Movements of the Wing in the Insect " (Revue des 

 cours scientifiques de la France et de I'Etranger), did not 

 appear until the 13th of February 1869. 



Professor Marey, in a letter addressed to the French 

 Academy in reply to mine, admits my claim to priority in 

 the following terms : — 



" J'ai constats qu'efiectivement M. Pettigrew a vu avant 

 moi, et repr6sent6 dans son M6moire, la forme en 8 du par- 

 cours de Taile de Tinsecte : que la m^thode optique a laquelle 

 j'avais recours est a peu pres identique a la sienne. . . . Je 

 m'empresse de satisfaire a cette demande legitime, et de laisser 

 entierement la priorite sur moi a M. Pettigrew relativement 

 a la question ainsi restreinte." — (Comptes Rendus, May 16, 

 1870, p. 1093). 



The figure-of-8 theory of walking, swimming, and flying, 

 as originally propounded in the lectures, papers, and memoirs 

 referred to, has been confirmed not only by the researches 

 and experiments of Professor Marey, but also by those of M. 

 Senecal, M. de Pastes, M. Ciotti, and others. Its accuracy is 



