1863.] 



463 



Experiment 10. A hollow brass cylinder, 6 inches long, 2 inches 

 in diameter, and pg^h ^ an mcn thick, was heated to redness and 

 cooled by half-immersion thirty-four times. 



The effect produced was the opposite to that which took place with 

 the iron cylinders, being an expansion instead of a contraction at the 

 water-line, the amount of which was 1 75 inch, and it was also ex- 

 panded on the lower edge '1 inch (see fig. 16). 



Fig. 16. 



One-half of full size. The dotted line indicates the original figure. 



Experiment 1 1 . A hollow gun-metal cylinder was heated to red- 

 ness and cooled twenty times by half-immersion. 



The thickness of metal being greater than in the last experiment, 

 the effect at the water-line was much less, but the lower edge had 

 expanded 1 inch. It began to crack all over at the last cooling. 



Experiment 12. A hollow tin cylinder was heated in linseed-oil 

 which was brought to a temperature of 400 Fahr. ; it was cooled by 

 half-immersion in water five times. 



2 L2 



