218 L. HARGRAVE. 



swung about two feet forward, and M soars with a deep bight in? 

 the cord to position B (Fig. 9), and then turns and rushes round 

 like a conical pendulum, jerking savagely at the hanging cord in 

 all directions. It then has to be caught as it is impossible to tell 

 what is real soaring and what is impulse derived from elasticity 

 of the poles and cords. 



Kite N was then attached to the horizontal cord by a piece o£ 

 fishing line and loaded with 2 Bbs. of lead. 



The area of N's propeller is 243 square inches = 1 -69 square feet 

 N's weight without lead 1 K>. OJ oz. 

 Lead weights ... ... 2 lbs. oz. 



3 lbs. Oi oz. = 3-016 lbs. 



Weight per square foot = 1*78 lbs. 



Kite N starts from a plumb position and ascends slowly at an 

 angle of about 45° to windward, it did it five or six times in spite 

 of the rain beating it down, and the drift of the hanging string 

 and a light line tied to the weight to keep it from dashing about. 

 Fig. 9 shows a side view of the experiments with M. 



It may be thought that it would be more conclusive if the 

 models were allowed perfect freedom. This matter has not escaped 

 consideration, and the reasons for not working with free apparatus 

 at present still hold good. By using the captive method, any 

 amount of skill and patience expended in the manufacture of the 

 soaring machine is amply repaid by its possession and the know- 

 ledge that the experiment can be repeated under similar conditions. 

 Whereas if the free method is used, a form that merely wanted a 

 little adjustment to be perfect, would frequently be smashed or 

 lost in the sea without anything remaining to show its defects or 

 lead to rapid improvement. 



Of course if I lived in the centre of a sandy plain, with numerous 

 assistants to make and repair constructions of my design, certain 

 advantages would accrue, but at present I try to make the utmost 

 use of the facilities at my disposal. 



