My Boyhood and Touth 



a big hawk's nest. "But that," he objected, 

 "would draw still bigger bothersome trampling 

 crowds about the place, for who ever heard of 

 anything so queer as a big clock on the top of a 

 tree?" So I had to lay aside its big wheels and 

 cams and rest content with the pleasure of in- 

 venting it, and looking at it in my mind and 

 listening to the deep solemn throbbing of its 

 long two-second pendulum with its two old 

 axes back to back for the bob. 



One of my inventions was a large thermome- 

 ter made of an iron rod, about three feet long 

 and five eighths of an inch in diameter, that 

 had formed part of a wagon-box. The expan- 

 sion and contraction of this rod was multiplied 

 by a series of levers made of strips of hoop iron. 

 The pressure of the rod against the levers was 

 kept constant by a small counterweight, so 

 that the slightest change in the length of the 

 rod was instantly shown on a dial about three 

 feet wide multiplied about thirty-two thousand 

 times. The zero-point was gained by packing 

 the rod in wet snow. The scale was so large 

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