Maiic/icstcr Memoirs, Vol. xliv. {igoo). No. II. 15 



tion may in the future be attacked with any prospect of 

 success. 



39. The plan, in brief, is to reverse the action of a 

 parachute by a vibratory motion, causing it to ascend 

 against the action of gravity, instead of using the apparatus 

 solely for the purpose of descending towards the earth as 

 heretofore. 



40. Let a parachute be constructed with a light frame- 

 work of steel, firmly stayed to a tubular central shaft, the 

 lower end of which forms the piston-rod of a gas or steam 

 motor. The sudden downward stroke of the piston will 

 cause the cylinder, with the car attached thereto, to rise 

 against the action of gravity, and a rapid succession of such 

 impulses will increase the height gained by each preceding 

 impulse until the desired elevation is attained. 



41. The alternating upward strokes of the piston may 

 be assisted by a valvular arrangement in the covering of 

 the parachute, and also by the rarefaction of the air on its 

 upper surface during the sudden downward stroke. I 

 have proved by experiments made some years ago that 

 such a rarefaction on the posterior surface of a plane 

 moved rapidly through the air does actuall)' occur, and I am 

 pleased to notice that Lord Rayleigh, in his recent lecture 

 at the Royal Institution, performed an experiment to 

 show the reality of this suction in the case of a bird's 

 wing, about which he said there had been much scepticism. 



42. When the power of ascension is once attained, the 

 horizontal movement, or travelling through the air, is a 

 comparatively minor problem, on account of the small 

 amount of power required for the purpose. This move- 

 ment may be brought about by inclining the vibrating 

 parachute from the perpendicular for the direction of 



