22 MR. J. MUIR ON THE RECOVERV OF IRON FROM OVERSTRAIN. 



Effect of Moderate Temperature on Recovery from Overstrain. 



The slow recovery t' iron from tensile overstrain which has been illustrated by the 

 examples already given, was found to be hastened to a remarkable extent by a slight 

 increase of temperature. Three or 4 minutes at 100 C. were found sufficient to 

 bring alnuit a complete restoration of elasticity ; and this, at the normal temperature, 

 could not be effected in less than a fortnight, with the material considered. 



Diagram No. VII. (Recovery at 100 C.) 



.- first 

 S.-zomina. After ft? I 



I. 6. 3. * 3. . 



Extensions - diminished as explained onpa.$e IS. 

 Scate :- 1 unit - ^ of an inch. '. * 



Before describing experiments which show this effect, it may be stated that experi- 

 ments were made (though perhaps they might be considered unnecessary) to show 

 that the tem{>eratures to be dealt with could in no way alter the elastic properties 

 of the material in its primitive condition. A virgin specimen was kept immersed in 



