Recent Ornithological Publications. 267 



india-rubber like little drum-heads, and connected by an air- 

 tight tube of the same material^ so that, the top of one being 

 raised or depressed, the top of the other will be moved almost 

 instantly in the reverse manner. On the top of one rests the 

 short arm of a lever, the long arm of which carries a point just 

 touching a moving strip of smoked paper or glass so as to record 

 thereon the movements generated through the tube, while the 

 top of the other basin is attached to the bird, the subjects of the 

 experiments being Pigeons, Wild Ducks, Buzzards, and Har- 

 riers, which were induced to fly from one end of a long room to 

 the other. In this manner one "drum-head," being pressed 

 against the bird's breast, was made to record the contractions of 

 the pectoral muscles; or two " drum-heads,^' connected by a rod, 

 fixed to the wing registered its actual motion relatively to the 

 bird ; while, again, by means of a little weight fastened to the 

 ''drum-head" attached vertically to the bird's back, any change 

 in the velocity of the flight produces a jerk, which shows its 

 amount; and, lastly, the same "drum-head" being attached 

 horizontally, each rise or fall of the bird is indicated. Besides 

 this mechanical apparatus an electrical one was also used, so as 

 to signal each stroke of the wing and its duration. From a 

 number of experiments M. Marey arrives at these conclu- 

 sions : — (1) that the down-stroke lasts longer than the up- 

 stroke : (2) that the axis of the wing moves, relatively to the bird 

 (a Buzzard flying almost horizontally), from the beginning of the 

 down-stroke, nearly vertically downwards, then slightly for- 

 wards, then downwards again, and more and more backwards ; 

 while during the up-stroke it moves at first backwards, but 

 towards the end forwards again into its original position : (3) 

 that the wing at the beginning of the stroke, partly from the 

 arrangement of the muscles, and partly from the resistance of 

 the air, turns rapidly about its axis ; and whereas before the be- 

 ginning of the down-stroke it slopes forwards and upwards, the 

 direction during the greater part of it is forwards and down- 

 wards ; towards the end of the down-stroke it turns back again, 

 and at the end is nearly horizontal, while during the up-stroke 

 the wing slopes greatly forwards and upwards : hence it appears 

 that, during the down-stroke, the bird receives an impetus for- 



