236 Aérial Locomotion. (April, 
described, and delineated by Dr. Pettigrew, and to this physio- 
logist undoubtedly belongs the high merit of first discovering 
the true principles of flight. 
Dr. Pettigrew published his discovery in the early part of 
1867,* and Professor Marey did not write upon the subject 
of flight till the end of 1868.t ‘There is, therefore, an in- 
terval of nearly two years in favour of Dr. Pettigrew. 
We think it right to draw attention to this circumstance, 
because Professor Marey does scant justice to Dr. Petti- 
grew, and because we detect in all Professor Marey’s wri- 
tings on flight traces of Dr. Pettigrew’s original discovery. 
This remark applies equally to Professor Marey’s theory 
and practice of flight. 
We hope to be able to prove the validity of our position, 
as we advance, by a series of parallel passages. The history 
of science demands that this course should be taken. We 
begin with the figure-of-8 itself. 
Professor Marey, in a letter addressed to the French 
Academy of Sciences, admitted Dr. Pettigrew’s claim to 
priority in the matter of the figure-of-8 movements made 
by the wing in space in the following terms :— 
“‘ T have ascertained that, in reality, Mr. Pettigrew has seen before me, and 
represented in his memoirt the figure-of-8 track made by the wing of the 
insect, and that the optic method to which I had recourse is almost identical 
Sects to satisfy this legitimate demand, and I leave entirely to Mr. Pet- 
tigrew the priority over me relatively to the question, as restricted.” 
(Comptes Rendus, May 16th, 1870, p. 1093). 
Since writing the above, Professor Marey has evidently 
been changing his views; for in his new work (‘‘ Animal 
Mechanism,” p. 187) he states that, “‘ notwithstanding this 
apparent agreement, our theory, and that of Dr. Pettigrew, 
differ materially from each other.” 
We have searched diligently for the points of disagreement, 
and find them trifling in character and few in number. The 
points of agreement, on the other hand, are numerous and 
important. 
Dr. Pettigrew, in his letter of “reclamation” to the 
French Academy,|| to which the foregoing, by Professor 
* «On the Various Modes of Flight in Relation to Aéronautics.”” Proceedings 
of the Royal Institution of Great Britain, March 22, 1867. 
‘© On the Mechanical Appliances by which Flight is attained in the Animal 
Kingdom.” Trans. Linn. Soc., vol. xxvi. (Read June 6th and zoth, 1867). 
+ Comptes Rendus. ‘Tome lxvii., No. 26, p. 1341. Dec. 28, 1868. 
+ “On the Mechanical Appliances by which Flight is attained in the Animal 
Kingdom.” By J. Bert PETTIGREW, MIEID).,  LEAIRES\. Trans. Linn. Soc., 
vol. xxvi. (Read to Linn. Soc. on June 6th and 2oth, 1857). 
|| Comptes Rendus. April, 1870. 
