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AERONAUTICS. 



tainly have a very graphic account of artificial wings in the 

 De Motu Animalium of Borelli, published as far back as 

 1680, i.e. nearly two centuries ago.^ 



Indeed it will not be too much to affirm, that to this dis- 

 tinguished physiologist and mathematician belongs almost all 

 the knowledge we possessed of artificial wings up till 1865. 

 He was well acquainted with the properties of the wedge, as 

 applied to flight, and he was likewise cognisant of the flexible 

 and elastic properties of the wing. To him is to be traced 

 the purely mechanical theory of the wing's action. He figured 

 a bird with artificial wings, each wing consisting of a rigid 

 rod in front and flexible feathers behind. I have thought fit 

 to reproduce Borelli's figure both because of its great antiquity, 

 and because it is eminently illustrative of his text.^ 



The wings (1) cfoe a), are represented as striking vertically 

 downwards {g h). They remarkably accord with those de- 

 scribed by Straus-Durckheim, Girard, and quite recently by 

 Professor Marey.^ 



Borelli is of opinion that flight results from the application 

 of an inclined plane, which beats the air, and which has a 

 wedge action. He, in fact, endeavours to prove that a bird 

 wedges itself forward upon the air by the perpendicular vibra- 



^ Borelli, De Motii Animalium. Sm. 4to, 2 vols. Romje, 1680. 

 ^ De Motu Animalium, Lugduni Batavorum apud Petrum Vander. Anno 

 MDCLXxxv. Tab. XIII. figure 2. (New edition.) 

 ^ llevue des Cours Scientifiques de la France de I'Etranger. Mars 1869. 



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Fig. 113.— Borelli's Artificial Bird. 



