■42 



POPULAR SCIENCE MONTHLY. 



sixty-four, the cells being four times as large. The kite is not as suc- 

 cessful as the preceding one. Dr. Bell's experiments have convinced 

 him that the small cells are better ; when the wind varies in strength as 

 in a squall, the shifting of pressure on a small cell is less than the 

 shifting on a large cell; hence the resultant shifting of pressure on a 

 kite built of small cells is considerably less than on a kite built of large 

 cells. Fig. 8 shows the method of attaching five pounds, a piece of 

 lead in this case; the kite is not disturbed by the weight. The kite 



Fig. 11. White Flier. Carrying it off the Field after the Experiment. 



shown in Figs. 9, 10 and 11 is also tetrahedral in form and built of 

 tetrahedral cells. It is twice as large as the red flier, being four 

 meters on a side. Fig. 9 gives a side view and Fig. 10 a front view 

 of the kite as it rests on its keel. The average pull of this kite in light 

 winds is 80 pounds; in a heavy wind it exceeds 150 pounds. 



The strength of the kites made of tetrahedral cells is something 

 remarkable. I have seen one of these kites towed on a tetrahedral float 

 for more than a mile on the bay at a speed of eleven or twelve knots 

 without breaking, though one end was dragging one foot under water 

 all the time. As I saw the kite pulled along I expected to see it 



