546 EEPORT — 1881. 



would be of the slightest value ; for supposing that a bird of 2 lbs. weight 

 displaces ^- of a cubic foot of air, or about 46 grains in weight onlj', the buoyancy 

 imparted to it would really amount to but 3 of 1 per cent, of the weight of the 

 bird. Besides which the force imparted to the wing of the bird is due to its 

 weight only, and were it as light as an equal bulk of air it could not fly at all. 

 The author next alluded to the upward stroke of the wing, and the theory that 

 in it the feathers separate so as to allow of the air passing through. There is 

 really no necessity for such action, because although the wing be rising in order 

 to repeat the downward stroke, it is all the time pressing against the air with the- 

 whole weight of the bird's body, and in that act of rising the wing has also a 

 propelling effect. 



He then proceeds to argue that the weight of the bird plays an active part in 

 its flight, and that this result arises from the action of that portion of the pectoral 

 muscle wliich depresses the wing. So great is the tension of this muscle that it 

 is highly probable that, in the case of those long-winged and heavy birds which are 

 able to fly without apparently moving a feather, the wings are kept extended 

 against tlie resistance of the air underneath without any voluntary effort of the- 

 bird. Its weight pressing upon the air causes this muscle to expand in raising 

 the wing, and aids in the effect of the downward stroke by its contraction. 

 The author exhibited a model with -wangs 4 feet from tip to tip and 3 feet 2 inches 

 from head to tail. The wings are actuated by M. Renaud's plan of strands of india- 

 rubber previously put into a state of tension, which in unwinding create a flap- 

 ping of the wings. By an india-rubber cord attached to the under part of the 

 wing and passing under the shaft to whicli the mechanism is attached, an equi- 

 librium between the two forces is attained : that is to say, the india-rubber strands 

 are wound up to that extent that the wings in rising stretch the india-rubber 

 cord — or, as the author calls it, the pectoral cord — until one force neutralises the 

 other : so that, held in the hand, there is no action. When liberated, and com- 

 mitted to the pressure of the nir underneath the wings, the weight of the model 

 causes the wings to be elevated, and therefore stretches the pectoral cord, which 

 in its contraction assists the power derived from the twisted rubber in depressing- 

 the wings arainst the weight of the model. During this action the flight is 

 deliberate and well-sustained for 40 feet or more. 



As, over and above this condition of equilibriimi, there is plenty of reserve- 

 power, the flight of the model is capable of great extension. 



The author argues from this that the power required to produce flight has 

 been much exaggerated, and that weight is an absolute necessity. He show^s 

 various forms of flight, but he believes that there can be nothing superior to the- 

 Teciprocating wing-action which propels and supports at the same time. He re- 

 commends, however, trial of an apparatus which, from his experiments, promises 

 success. Is it pos.sible, he asks, to control some arrangement in the nature of a 

 parachute by altering its form and making it longitudinal — giving it, in fact, a 

 head and a tail. Such an apparatus, made by himself, was liberated from a balloon- 

 which rose from Woolwich Arsenal, and it travelled back, by the aid of gravity 

 alone, to the Arsenal— of course against the breeze which wafted away the balloon 

 — a distance of half a mile. 



He argues from this that if the fabric can be manipulated so that propulsion- 

 also can be imparted to it, then some encouraging results would be likely to 

 follow. He showed a model of large size upon this principle, and how, by the- 

 action of the wing-arms, a wave is transmitted from head to tail along a loose 

 surface in shape like a kite. This loose surface necessarily requires a fall before it 

 can be inflated by the air underneath. The wave-motion is then found adequate 

 to its propulsion. An estimate of the power required to propel and support 

 100 lbs. weight in the air has been made from the data given from this model, 

 which weighs with added lead 2i lbs., and it is believed that ^ h.p. will be required 

 for each 100 lbs. 



Having arranged about 300 square feet of a suitable fabric, the author pro- 

 poses that, to effect a start, the apparatus, having a flat-bottomed carriage, shall be- 

 placed upon a wheeled platform or truck, the two front being higher than the 



