216 



L. HAKGKAVE. 



I have noticed that soaring is easier in a wind velocity that is 

 increasing than when it is decreasing, and attribute this to 

 volumes of air of high density and velocity driving in under 

 volumes of lower density and velocity : the contiguous surfaces 

 will then cause eddies in the combined mass rotating in the same 

 direction that the soaring vortex does : that is, the upper part of 

 the eddy moving to windward and the lower part to leeward, one 

 of these would be more readily caught and held by the propeller 

 than when the contrary conditions prevail. 



Every detail of Kites M and N as remodelled are shown in 

 Figs. 6, 7, and they now contain all the necessary parts of a 

 practicable soaring machine to carry one man, and I expect to 

 hear ere this is in print, that some of the gliding machines on the 

 shore of Lake Michigan have been fitted with soaring curves, the 

 trials of which are certain to be successful. 



The observations made on August 31, 1898 are as follows: — 

 Kites M and N to the beach. Very steady east wind, twelve to 



Soaring fClU M. 



Fig. 6. 



