44 M1; .,. M , ,,; OH T11K RKCOYKKY OK IKON KKOM OVF.KSTKMN. 



normal temi-ratu,vs. by keepiug the piece for ,, * mim,t,s !lt a temperature 

 uch as 100 C is shown in the following series of OOmpre instrument readings. 

 This third series of readings was obtained from compression specimen taken from 

 the same overstrained rod as the last; but in the present case the specimen WM 

 boiled in water for 6 minutes before being tested. This test is illustrated by Cum- 

 No. 3, Diagram XIII. 



T.mii. Series of Compression Readings. (Showing Recovery of Elasticity produced 



by 6 Minutes' Boiling.) 



Comparison of the differences in this table and those in the last, or comparison of 

 Curves 2 and 3 of Diagram XIII. , clearly shows the large effect produced by the 

 6 minutes at 100 C. Comparison of the first and third series of readings, or of 

 Curves 1 and 3, Diagram XIII., seems to indicate that the 6 minutes' boiling has not 

 sufficed to produce quite perfect recovery of elasticity. In Curve No. 4 of this 

 diagram the readings need not be tabulated there is shown the testing of a 

 specimen very similar to that employed for Curve No. 3, but in this case it was 

 certain that recovery was complete. The specimen was not taken from the same 

 overstrained portion of a bar as that from which Curves Nos. 2 and 3 were obtained, 

 but from another portion of the same material, which had been similarly overstrained. 

 Before the compression specimen was cut off, the overstrained tension specimen had 



