88 
MR. H. TOMLINSON ON THE INFLUENCE OF STRESS 
a certain load has been reached, the resistance begins, as in other metals, to increase. 
The curves in Table X. are drawn with their abscissas to represent the alteration of 
resistance—for the lower one on a scale of 1 division of the platino-iridium wire to the 
millimetre, and for the upper one on a scale of 25 divisions of the platino-iridium wire 
to the millimetre. 
Table X.— Curve showing the total permanent alteration of electrical resistance 
produced by longitudinal traction from 10 to 24-f kilogs., and curve showing the 
permanent total alteration of electrical resistance produced by longitudinal traction 
from 0 to 14 kilogs. 
In both curves the ordinates represent the number of kilogrammes on the wire to a 
scale of ‘2 kilog. to the millimetre. The lower curve which represents the permanent 
alteration of resistance produced by loads up to 14 kilogs., shows that the resistance 
decreases to an extent which is nearly proportional to the load up to 6 kilogs. ; here a 
sudden leap is made of rapid decrease of resistance, but on reaching the next load, 
8 kilogs., the curve turns, and just at the 12th kilog. there occurs a sudden and rapid 
increase of resistance. The upper curve which starts from the 10th kilog. shows 
that the rapid increase begun at the 12th kilog. is continued to an extent which is 
nearly proportional to the load up to the breaking point of the wire. The nature of 
