TETRAHEDRAL KITES. 



145 



smaller kites, lie would succeed in obtaining a successful form for a 

 flying machine. 



There are two ways in which Mabel II. might be towed — on wheels 

 along a track or on floats on the surface of a lake. Dr. Bell preferred 

 to try the second method first, as it is simpler and easier. 



With tetrahedral frames he built three long boats and covered them 

 with oilcloth to make them watertight. The boats possess great 

 strength, and yet, because of their tetrahedral structure, are so light 

 as not to overweight the kite. 

 The three boats were then ranged 

 parallel to one another and the 

 whole structure placed upon and 

 securely fastened to them. 



Fig. 15 shows Mabel II., just 

 before she was launched. Thi^ 

 figure and Figs. 16 and 17 give 

 an excellent idea of the construc- 

 tion of the kite. Across the floats 

 extend two bridges, built of tetra- 

 hedral cells. Resting on the bridges 

 are four large kites, like the one 

 shown in Fig. 8. The spaces be- 

 tween the four kites are filled with 

 smaller tetrahedral cells. In all 

 there are 272 cells in the structure. 



Fig, 18 shows the kite fioating 

 merrily on the water waiting to be 

 put to the test. With her tiers of 

 red Avings above and white wings 

 below she was a beautiful sight. 

 But would she fly? A small model 

 of Mabel II., shown in Fig. 13 

 had flown beautifully on land. The 

 flying weight of this model was 

 greater than the flying weight of ]\[abel II., and Dr. Bell had 

 therefore every reason to believe that Mabel II. would also fly if he 

 could raise her. 



When everything was ready Mabel II. was towed out to the center 

 of the bay and her flying line cast aboard the steamer which Dr. Bell 

 had engaged for the experiment. The flying line was made fast to a 

 cleat on deck and the steamer started ahead at full speed, twelve or 

 thirteen knots an hour. 



But Mabel II. was working under two bad handicaps — first, a 



VOL. LXIV. — 10. 



Fui. 14. Testing one of the Boats of 

 Mabei. II. 



