388 
Prof.  Morley  and  Mr.  Tomlinson  on  Tensile 
Table  VII.  and  in  fig.  6,  which  has  been  plotted  from  the 
table.  The  readings  were  taken  immediately  after  the  applica- 
tion of  the  4-ton  loads,   so   that  little  creeping  took  place. 
Table  VII. 
Extensometer- 
Time  in  Minutes. 
Load  in  Ton?. 
reading  in 
50^05  inch  units.     ; 
... 
o 
200 
"6 
4 
502 
5 
4 
493 
28 
4 
483 
46 
4 
482 
61 
4 
480 
131 
4 
476 
266 
4 
470 
1 
For  this  reason   the  readings  are  less  than  for  the  4-ton  load 
in  the  test  after  overstrain  of  specimen  No.  9. 
Rate  of  "  Creeping  "  during  Loading. 
The  early  curvature  of  the  load-extension  curves  for  speci- 
mens Nos.  8  and  9  in  their  original  condition  is  probably 
largely  due  to  that  part  of  the  extension  which  takes  time  to 
develop  and  which  is  generally  called  "  creeping/'  The 
rate  at  which  u  creeping  "  took  place  at  two  different  loads, 
3  tons  and  5*5  tons,  was  observed  both  before  and  after  over- 
straining ;  the  specimen  used  (No.  12)  was  cut  from  the  same 
bar  as  Nos.  8  and  9,  and  was  overstrained  by  a  load  of 
11  tons.  The  results  are  given  in  Tables  VIII.,  IX.,  X._,  and 
XL,  which  are  plotted  in  fig.  7  ;  the  broken  lines  show  the 
rate  of  creeping  before  overstrain  has  taken  place,  and  the  full 
lines  show  the  corresponding  rates  after  overstrain.  The 
extensometer-reading,  with  no  load  on  the  specimen,  was  200 
in  each  case,  and  the  extension  was  measured  on  a  length  of 
8  inches. 
On  specimen  No.  15  an  attempt  was  made  to  separate,  as 
far  as  possible,  the  plastic  extensions  due  to  "  creeping,"  from 
the  elastic  extensions  which  develop  immediately  after  the 
load  is  applied.  For  this  purpose  the  jockey  weight  of  the 
testing-machine  was  set  in  succession  to  the  necessary  posi- 
tions before  the  loads  wrere  applied  to  the  specimen  by  the 
hydraulic  ram.     After  this  the  load  was  very  quickly  applied, 
