402 SEVENTH REPORT—1837. 
On comparing the above with Table No. XII, preceding it, 
there will be found a greater proportionate deflection in both 
the cold and hot blast bars than is observable with the lighter 
weights of 336 lbs., and in both instances the deflection is greater 
in the hot than in the cold blast. The same is the case in ex- 
periment 2nd of the next Table, where the deflection indicated 
by 448 lbs. is less than what is exhibited on the hot blast with 
336 lbs., being as 1°437 to 1°803. This may be accounted for 
by the bars which were newly cast containing, in all proba- 
bility, a greater proportion of carbon, and consequently having 
more ductility than those in Tables No. XII and No. XIV. 
The ratio of increase in the deflections is much higher in the 
cold blast iron than the hot; and notwithstanding the silent 
and apparently progressive approach towards rupture, there is 
every appearance of a long and tedious experiment. It cannot 
however be doubted that fracture will sooner take place in the 
cold than the hot blast, as the former is advancing to that point 
with greater rapidity, or in the ratio of 1000 to 628. We may 
therefore expect the bar from the cold blast iron to be the first 
to give way, and probably about the time when the deflection 
verges on two inches. 
a 
