ANATOMY AND PHYSIOLOGY. 113 
horizontal plane. But as she lies obliquely on the 
air in fight this plane slopes downwards and back- 
wards, so that the down stroke of the conjoined 
wings must be delivered forwards. 
It is quite unnecessary to say that a mere flapping 
of the wings, to and fro, however rapid, regular, or 
long-continued, could not do anythmg in the way of 
flight; it would disturb the air and nothing more. 
Some arrangement must be adopted to render the 
stroke more effective in one direction than the other. 
To explain how this is accomplished will require, and 
must excuse, a long digression on the mechanism of 
flight. 
The problem of flight has always attracted much 
attention, and, from the time of Deedalus downwards, 
mechanical invention has been strained to contrive 
flymg machines on the most various principles, all 
agreeing only in one point, that of failmg to accom- 
plish their object; all legends to the contrary not- 
withstanding.* The Aéronautical Society of Great 
Britainf has had no better success as yet than private 
adventurers in the same field of air, but we are much 
indebted to it for having elicited an essay from 
Mr. Wenham,{ explainmg the correct principles on 
* See Browne’s ‘ Religio Medici,’ Gairdner’s edition, p. 38, and 
Appendix C, for references on this subject to Du Bartas and others. 
+ ‘ First Annual Report,’ small 8vo, London, 1866, records some 
very curious experiments on aérostation, and enumerates no less than 
forty patents which have been taken out since 1842 in connection 
therewith. 
t On Aérial Locomotion, and the Laws by which heavy bodies 
impelled through the air are sustained. ‘Engineering.’ Ap. 19, 1867, 
p. 360, and ‘ Annual Report,’ sup. cit. 
I 
