DR BELL'S TETRAHEDRAL TOWER 



AN outlook tower, unique in design 

 . and construction, has been recently 

 erected by Dr Alexander Graham Bell 

 at his summer home in Baddeck, Nova 

 Scotia. The tower reaches a height of 

 nearly 80 feet, and yet neither scaffolding 

 nor derricks were emplo3'ed in building 

 it. It is made of the tetrahedral cells in- 

 vented by Dr Bell and described by him 

 in the article on "Aerial Locomotion," 

 published in the January, 1907, number 

 of this Magazine. The accompanying 

 illustrations represent the process of con- 

 struction. Picture i shows several piles 

 of tetrahedral cells made of ordinary gal- 

 vanized iron piping. These cells were 

 riveted together until two legs of the 

 tower were completed and joined at the 



upper end, as in picture 2. The third leg 

 was then shoved up by jack screws, suc- 

 cessive layers of cells being constantly 

 added, as in picture 3. The completed 

 tower appears in pictures 4 and 5. 



This considerable structure weighs 

 less than 5 tons, and yet can carry a 

 great weight. It is remarkable, not only 

 for its strength and lightness, as well as 

 cheapness, but also for the fact that it 

 was put together in about 10 days by 

 several unskilled laborers, and that every 

 part of the work was done on the ground. 

 No one was obliged to leave the ground 

 until the tower stood erect and com- 

 pleted. Mr C. Baldwin, C. E., of To- 

 ronto, superintended the construction of 

 the tower. 



Photo by Douglas McCurdy 



I. The Tetrahedral Cells, of which the Lookout Tower was Constructed 



