At the first meeting of the Aeronautical Society of Great Britain in June, 1866, the author read a paper “On Aerial Locomotion and the Laws by which Heavy Bodies impelled through Air are Sustained.” Since that date, the writer has only occasionally reverted to the subject, but has never been convinced that flight is impossible for man, considering the apparent ease with which large birds traverse the air.

The power required to maintain the flight of the screw vanes mentioned in the paper (now extensively used for flying-shot practice), was estimated at the rate of three-horse power for each hundred pounds raised. This is widely in excess of the reality, because when the first force that causes ascension is exhausted, the instrument in its subsequent descent, acts as a mere dirigible parachute. This is a most extravagant means of absorbing power. For example, a man weighing 150 lbs. attached to a parachute having this number of square feet, descending 1,300 feet per minute, will be expending six-horse power on the yielding air.