206 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 27 



ness by raising and lowering a screw in the slot of the head of which they rested, 

 and which was threaded in the end of the small guy-post. Upper and lower guy- 

 wires, running from the main ribs to the guy-posts on the aerodrome, as al- 

 ready described, and as is clearly shown in the drawings, Plates 52 and 54, com- 

 pleted the guy-wire system for the wings, except for the " drift wires," which 

 for the front wings were run from the lower side of the mid-rib to the bow- 

 sprit at the front of the machine, and for the rear wings to the main frame. 

 Each wing when completely assembled weighed approximately '29 pounds, 

 and had a rectangular surface 22.5 by 11.5 feet (measured on the chord of the 

 curve), or 2G0 square feet, making the weight per square foot equal about 50 

 grammes, rather less than 1.5 times as much per square foot as the wings for 

 the steam-driven models. The total supporting surface of the aerodrome was 

 1040 square feet, and as the aerodrome when equipped for flight weighed, in- 

 cluding the aviator, 850 pounds this gave 1.22 square feet to the pound, or 0.82 

 pound to the square foot. Although this was a somewhat larger proportion 

 of weight to supporting surface than it had originally been expected to have, 

 there is every reason to believe that it was sufficient, for the quarter-size model, 

 when weighted so that it had 1.22 square feet to the pound, flew well, as will 

 later appear. 



