

Anomalous Efects on First Loading a Wire. 619 



4. The absorption of the salt is directly proportional to 

 the amount of salt present in solutions. 



5. Solutions absorb /3 rays according to the same laws as 

 solids. 



6. The absorption by compounds follows an additive law. 



7. Relative absorption depends upon the internal structure 

 of atoms but is independent of the arrangement of the atoms 

 in the molecules. 



I have much pleasure in expressing my gratitude to 

 Prof. E. Rutherford for his permission to work in his labo- 

 ratory and for his kind interest in this work. 



Manchester, 

 January, 1910. 



LXV. Anomalous Effects on First Loading a Wire, and 

 some Effects of Bending Overstrain in Soft Iron Wires. 

 By A. I. Steven, M.A., B.Sc, Assistant Lecturer and 

 Demonstrator in Physics, University of Liverpool* . 



IN the recently published text-book on " Properties of 

 Matter/' by Poynting and Thomson, there is a para- 

 graph under the title " Anomalous Effects on First Loading 

 a Wire " (p. 58), in which notice is taken of the fact that 

 the extension produced by a given load is, in general, different 

 on the first test from that obtained in subsequent ones. It 

 does not seem, however, to have been noticed that the 

 '" anomalous" stress-strain diagrams obtained under these 

 circumstances bear a close resemblance to those obtained, say, 

 in the case of an iron bar immediately after a severe longi- 

 tudinal overstrain. Thjs apparent defect of Elasticity has been 

 noticed by others, and notably by Muir (Phil. Trans., A. 

 cxciii. p. 1), who investigated the effect of temperature on 

 the elastic recovery of iron. If the resemblance had been 

 noticed, it seems probable that the determining factor in the 

 production of such anomalies would have been discovered, 

 for every wire after manufacture is subjected to a non-homo- 

 geneous overstrain by being wound on a circular bobbin of 

 dimensions comparatively small. If the wire remain on the 

 bobbin, probably part of the internal stress disappears before 

 the wire is tested, in the same way as iron gradually recovers 

 its elasticity if left to itself, but when the wire is wound off 

 the bobbin for testing, another set of stresses is superposed on 

 the previous residual internal stress. These internal stresses 



* Communicated by Prof. L. R. Wilberforce. 



