We shall never be able to imitate the flight of the soaring birds. We cannot hope to make a sensitive apparatus that will work quick enough to take advantage of the rising currents of air, and he who seeks to fly has this problem to deal with. A successful flying machine, moving at a high velocity, is likely at any time to encounter downward currents of air, which will greatly interfere with its action. Therefore flying machines must, in the very nature of things, be provided with sufficient power to propel them through various currents of air, after the manner of ducks, partridges, pheasants, etc. +------------------+-------+--------+-----------------+ | | | | Corresponding | |Common Name. |Sq. Ft.|Lbs. per|Speed for a Plane| | |per Lb.|Sq. Ft. | at 3° in Miles | | | | | per Hour. | +------------------+-------+--------+-----------------+ |Bat, | 7·64 | 0·131 | 15·9 | |Swallow, | 3·62 | 0·276 | 23·1 | |Lark, | 3·06 | 0·327 | 25·1 | |Sparrow hawk, | 3·00 | 0·333 | 25·3 | |Sparrow, | 2·42 | 0·414 | 28·2 | |Gull, | 2·35 | 0·426 | 28·6 | |Owl, | 2·26 | 0·443 | 29·2 | |Crane, | 2·02 | 0·495 | 30·9 | |Rook, | 1·74 | 0·575 | 33·3 | |Plover, | 1·38 | 0·725 | 37·4 | |Balbuzzard, | 1·26 | 0·795 | 39·2 | |Egyptian vulture, | 1·18 | 0·848 | 40·4 | |Duck, | 0·864 | 1·158 | 44·2 | |Grey pelican, | 0·732 | 1·365 | 51·3 | |Wild goose, | 0·586 | 1·708 | 57·4 | |Turkey, | 0·523 | 1·910 | 60·6 | |Duck (female), | 0·498 | 2·008 | 62·2 | | „ (male), | 0·439 | 2·280 | 66·2 | +------------------+-------+--------+-----------------+ CHAPTER III. FLYING OF KITES.