Tetrahedral Principle in Kite Structure 249 



"ferent stages in the process of construc- 

 tion : • 



1. Tetrahedral cell employed in mak- 

 ing the framework of the wind-break. 



2,3, and 4. The wind-break in pro- 

 cess of construction. 



Plate V. — 1. Wind-break completed, 

 showing canvas rolled down. 



2. Wind-break showing canvas raised . 



3. End view of wind-break. 



4. Model of the framework for a tet- 

 rahedral house. 



5. Tetrahedral nuts for fastening tet- 

 rahedral frames together. 



Plate VI. — 1. The observation-house 

 where the kite experiments are observed 

 and noted. The house itself is of the 

 tetrahedral form. 



2. Front view of winged boat, the 

 framework of which is constructed of 

 tetrahedral cells. 



3. Another view of the winged boat. 



4. The winged boat in the air. . . 

 Plate VII. — 1. A tetrahedral frame of 



tetrahedral cells, winged on the outside, 

 with an internal aeroplane. 



2. A kite formed of two tetrahedral 

 structures like that in No. i connected 

 together by a framework composed of 

 tetrahedral cells. 



3. The kite of No. 2 fitted with com- 

 pound tetrahedral frames at either end 

 converting the framework into the 

 form of a boat. This same kite with 

 the framework covered constitutes the 

 winged boat shown in Nos. 2, 3, and 

 4, Plate VI. 



4. The kite of No. 2 in the air. 

 Plate J VII. — 3. Non-capsizable kite. 



When from any cause the kite tips to one 

 side the lifting power increases on the 

 depressed side and diminishes on the ele- 

 vated side, thus tending to right the kite. 



1. Non capsizable kite flying from 

 flag-pole. 



2. Tetrahedral frame used in the con- 

 struction of the winged boat shown in 

 Plate VI ; also used in the structures 

 shown in Plate VII. 



4. Portions of the kite shown in Plate 



VII, No. 3, in sections ready to be tied 

 together. 



Plate IX. — Photographs illustrating 

 mode of studying the behavior of bodies 

 in the air, whether these bodies are capa- 

 ble of supporting themselves in the air 

 or not. They are attached to the end 

 of a bamboo pole by a cord sufficiently 

 short to prevent them from dashing 

 themselves to pieces upon the ground. 

 A flag-pole is used for large kites, but 

 a bamboo fishing rod is more convenient 

 for testing the flying qualities of the 

 smaller structures. In the cases shown 

 in the plate, the cord is a manila rope, 

 about ;<4 inch in diameter. Such a rope 

 is too heavy for light kites, but smaller 

 cords make so little impression on the 

 photographic film that it is often diffi- 

 cult when such cords are used to un- 

 derstand the conditions of an experi- 

 ment from a photograph. 



1 . A single set of triangular cells con- 

 stituting a hexagonal figure with six 

 interior radial wings. 



2. A single set of triangular cells con- 

 stituting the figure of a triangle within 

 a triangle. 



3. A kite with three sets of triangular 

 cells. 



4. Kite shown in No. 3 flying from 

 a bamboo pole. 



5. Two-celled triangular kite with 

 rope attached to rear edge of front cell. 



6. Same kite shown in No. 5 flown 

 by the bow. 



Plate X. — These photographs illus- 

 trate experiments with kites formed 

 partly of open tetrahedral cells, with 

 the spaces between the cells covered. 



1. Kite with two pentahedral cells 

 close together, each cell having three 

 of its five faces covered. The rectan- 

 gular part of the kite is braced diag- 

 onally by means of tightly stretched 

 wires. 



2. Same kite shown in No. 1 at a con- 

 siderable elevation in the air. 



3. Similar kite with four pentahedral 

 cells close together, each cell having 



