124 
PROF. W. E. DALBY: RESEARCHES ON THE ELASTIC 
The permanent set QZ measured from the new origin Q is (F0127 inch. The total 
permanent set is thus 0'67 + 0'0127 inch = 0'6827 inch. The unproportional elastic 
recovery is ZY = 0‘0244 inch. 
§ 6. Looping a General Property of Metals. 
Records of looped diagrams are shown in the following figures. The load scale is 
varied to bring out the shape of the loops. 
The extension scale is substantially, l|- inches measured horizontally on the diagram 
represents T tjo inch extension of the gauge length. The diagrams are reproduced as 
taken, the object being to compare the elastic line and the loop formations. 
Staffordshire Iron. —Fig. 7. The limit of proportionality is reached at 3'5 tons; 
Fig. 7 (iron). 
11 4 tons per sq. inch. Ihe yield is reached at 5'1 tons; 16 tons per sq. inch. The 
load then drops to about 4'7 tons. The loop area is not large, but the area increases 
progressively. 
Steel. Carbon 0 8 per cent., fig. 8. The limit of proportionality is reached at 
about 8 tons; the yield at 8 *8 5 tons. There is a slight drop at the yield load. The 
