ON STRESSES IN OVERSTRAINED MATERIALS—SUMERIAN COPPER. 269 
An attempt to obtain agreement on definitions immediately discloses differences 
of conception and opinion of a fundamental nature, and it is very important that an 
effort be made to obtain agreement between physicists and electrical engineers on 
these fundamental points. 
We therefore consider it inadvisable to issue a definitive report at the present 
juncture, but recommend that the Committee be reappointed and that Sir R. Glaze- 
brook, Dr. W. E. Sumpner and Dr. D. W. Dye be added to the Committee. 
a 
Stresses in Overstrained Materials.— Report of Committee (Sir Hunry 
Fow er, Chairman; Dr. J. G. Docnerty, Secretary; Prof. G. Cook, 
Prof. B. P. Hatex, Mr. J. 8. Witsoy). 
_ ‘Tue programme of work set out in previous interim reports has been proceeded with, 
_ and the Committee submit as their report for this year the following contributions, 
_ embodying a general survey of the phenomena of yield in mild steel under various 
types of stress. 
1. ‘ An investigation of the hardness of a steel tube along certain Liiders or Piobert 
lines.’ By Sir Henry Fowler, K.B.E. (Pubd. in Engineering, vol. cxxxii, p. 299.) 
: 2. ‘ Change in indentation hardness of test-pieces resulting from varying amounts 
of deformation or plastic flow during the application of tensile stress.’ By Sir Henry 
Fowler, K.B.E. (ibid., p. 420.) 
t 3. ‘ The phenomena of tensile yield in mild steel and iron.’ By James G. Docherty 
and F.W. Thorne. (Jbid., p. 225.) 
4. ‘The upper and lower yield points in steel exposed to non-uniform distribution 
of stress.’ By Prof. G. Cook, D.Sc. (Lbid., p. 343.) 
5. ‘ Plastic strain in relation to fatigue in mild steel.’ By Prof. B. P. Haigh, 
D.Se., and T. 8. Robertson, B.Sc. (Ibid., p. 389.) 
| (Note.—These papers were published in Engineering, and by the courtesy of the 
editor have been reproduced by the Association, and may be obtained—gratuitously 
__ by members of the Association entitled to the Annual Report : price to others, 1s. 6d.— 
on application to the British Association, Burlington House, London, W. 1.) 
Sumerian Copper.—Report of Committee (Mr. H. J. E. Peake, 
Charman; Mr. G. A. Garrirr, Secretary; Mr. H. J. Batrour, Mr. 
L. H. Duptey-Buxton, Prof. Gorpon CuiLpe, Prof. C. H. Drscu, 
Prof. H. J. FLEurRs, Prof. 8. Lancpon, Mr. E. Mackay, Sir FLInDERS 
Perriz, Mr. C. Lzonarp Woo.LeEy) appointed to report on the probable 
source of the supply of copper used by the Sumerians. 
(By Prof. C. H. Descu, F.R.S., University of Sheffield.) 
Fourth Interim Report. 
‘Durine the past year Mr. E. 8. Carey has been engaged intermittently on analytical 
work for the Committee, and a quantity of micrographice work has also been carried 
out. The largest number of specimens during the year has been received from 
nae: Daro. (The balance in every case represents copper.) The results are as 
OMOWS :— 
Level in ; eek 
Tin Lead Tron Nickel 
gro. acta aa ei per cent. per cent. | percent. percent. | 
9366 23-54 4-9 6-3 | thal tr. 
9368 22-88 _ — tr. tr. 
9376 24-17 — tr. tr. tr. 
9392 23-72 13-7 — tr. tr. | 
9421 22-92 — tr. . tr. 0-84 
— 9442 24-34 22-1 14-9 tr. tr. 
