Physics 551 



a lack of confidence in the feasibility of extensive aerial navi- 

 gation by any of the methods then proposed, except by float- 

 ing with the air current in a balloon of sufficient size and 

 of sufficient impermeability to gas to enable it to maintain 

 a high elevation for some time. As might be expected, he 

 counseled more extensive experimentation on land before 

 crossing the ocean was attempted. 



The Report for 1863 contains an elaborate account by 

 Arago of several balloon ascensions made in the interest of 

 the advancement of science, and also a brief sketch of some 

 of Mr. Glaisher's ascents. The subject is continued in subse- 

 quent Reports, one paper, " On the Various Modes of Flight," 

 in 1867, deserving especial mention, on account of the great 

 amount of information it contains and its clear enunciation of 

 fundamental principles. It is a reprint from the Proceedings 

 of the Royal Institution of a lecture given by Doctor James 

 Bell Pettigrew. A careful study of the flight of birds, bats, 

 and insects is followed by a discussion of the possibility of 

 human flight, and the importance of a "screw" in aerial navi- 

 gation is enlarged upon. 



In the Report for 1869 the matter of flight in the animal 

 kingdom receives attention in the publication of Marey's 

 celebrated lectures on that subject. In the Report for 1889 

 there is a reprint of a very able discussion of the subject 

 of aerial locomotion by F. H. Wenham, first read before the 

 Aeronautical Society of Great Britain, and published in the 

 annual report of that society for the year 1 866. 



In the mean time the study of the whole question of 

 aerial navigation, whether by animals or by men, was destined 

 shortly to receive a new impulse through the labors of a small 

 number of scientific investigators who, undismayed by the 

 prevailing belief in the absurdity of the thought of practical 

 flying machines, had attacked the problem in a manner in 



