[March 5, 



Fig. 2. 



WL 



One-eighteenth of full size. 



The upper edge, or that cooled in air, had contracted 8 inches, or 

 2 J th its entire length, and slightly increased in thickness ; while the 

 lower edge, cooled in water, had expanded *875 inch, making a dif- 

 ference between the two circumferences of 8*875 inches. The breadth 

 remained unaltered (3 inches), and kept perfectly straight. 



Fig. 3. 



Section showing the amount of contraction. One-half the full size. The dotted 

 lines show the original form. 



The quality of the iron was afterwards tested by pieces taken from 

 the upper and lower edges, and also from the centre ; the fibrous 



