Vhjing-fish FViijhf, 101 



arc, first, tlu; '' .salllii.!^ " or skiinniirig flight of Ijinls (sWiiUows 

 beiiiL^ usually mentioned), and, secondly, |);iracliute.s. 



For purposes ot" comparison in tlii.s examination, we will 

 take a typical flying-Hsli. I have the wings of one, \\liicli 

 flew on board a steamer on which 1 was travelling, before me 

 as I write. Its weight was just over a pound, and it had a 

 wing-area of ()2 square inches, very libeially computed. 



Let us consider the bird-flight first. Concerning this we 

 have certain recognized facts to guide us, for which I refer 

 3-eaders to Professor E. J. Marey^s work on ' Animal 

 Mechanism' (International Science Series, vol. xi. [)p. 22 L- 

 225, 1874). 



We are specially concerned in his acceptance therein of 

 the division of birds into two main classes, viz., those 

 largely given to '^ sailing '' or still-wing flight (which class 

 is found to be endowed with a large wing-surface), and those 

 which confine themselves more to the "rowinsr^^ or wins:- 

 flapping flight (which, as a class, has short and narrow 

 wings). 



" If,'' says Professor Marey {loc. cit. p. 22J), " we compare 

 together two rowing, or two sailing birds . . .," arranging as 

 far as possible " to have no difference between them except 

 that of size, we shall find a tolerably constant ratio between 

 the weights of these birds and the surface of their wings." 

 Tables are added of this ratio in various birds, as found by 

 dividing the square root of their wing-surface in square 

 centimetres by the cube root of their weight in grammes. 



1 will from these tables give this ratio for three of the 

 sailing-birds and for three of the rowing-birds, including the 

 two lowest ratios of the latter. I will add on my own 

 account the ratio for the flying-fish, which is quite properly 

 comparable with birds in this respect. (See table, p. 1()2.) 



Note the place of the flying-fish. It is quite in its proper 

 position as a very low order of wing-flapper, requiring great 

 wing-speed to sustain it in air. Note also the representative 

 of the swallow tribe, weighing considerably under an ounce, 

 in its proper place in the sailing class. The Ilirundo rustica^ 

 or swallow proper, would doubtless hold a higher place still — 

 our principal parallel, whose featherweight ought to have 

 protected us from the comparison. 



1 he figures should be convincing ; I will not, therefore, 

 comment more upon this, but proceed to another test, viz. to 

 find what size of wing a one-pound (453 grammes) fish would 

 recjuire to raise it into the sailing class. No birds are dealt 

 with by ]\Iarey of exactly one pound weight ; I will therefore 

 take the next above an<l the ne.Kt bcdow that weight. 



Ann. tC' Maij. X Uiil. Ser. 7. Vu!. xvii. 11 



