386 SEVENTH REPORT—1837. 
Comparative results of Coed-Talon No.3. 
Distance between supports, 4 ft. 6 in. and 2 ft. 3 in. 
Strength of Cold Blast Iron.| Strength of Hot Biast Iron. Ratio of strengths. 
561°7 an, 499-5 : 
2140} 537'8 492.1 495°8 1000 : 922 
1195°7 : 1044-0 4 
jo7o0 f 11878 10775 f 10607 1000 : 932 
Mean ratio of strengths...... 1000 : 927 
Results of products and ratio to resist impact. 
Product of strength by ulti- | Product of strength by ulti- 
mate deflection in Cold Blast mate deflection in Hot Ratio of products, or of 
power to resist impact. 
Tron. Blast Iron. 
ee OORT 794-7 | 09, 
7581 f S12 eg } 782-2 1000 : 941 
589°5 1 arn. 413-2] jor, 
to10 $470 2 se }427 9 1000 : 910 
Mean ratio of powers to sustain impact ...... 1000 : 925 
Modulus of elasticity in lhs. for a hase of an inch square. 
Cold Blast Iron...... 17276800 
PITGY caveccsciecdissess 16927200 
Mean...... 17102000 
Hot Blast Iron ...... 14732600 
WaGHO sate nee ce encase = 14683200 
Mean...... 14707900 
If we carefully examine the different experiments in these and the preceding tables, 
it will appear obvious that the hot blast is in every instance the weaker iron, and 
whether it is viewed in the long or short specimens, the same marked difference in 
strength is apparent. It is also clear that the No. 3 hot blast is an iron of greater 
power than the second quality made by hot blast from the same ore. On contrasting 
the tables, it will be found that the No. 3 iron exceeds the No. 2 in its power to resist 
a transverse strain nearly one-fifth, and considerably more in its resisting power to 
sustain impact, this being in the ratio of 1000 to 766. 
I have pointed out the defect of the No. 2 iron, not so much for comparison be- 
tween the hot and cold blast, as from a desire to show the difference which in general 
exists between the two qualities. In preparing castings for the purpose of supporting 
great weights, it will be necessary to have reference to the No. 3 iron, as the best 
adapted for the purpose; it will be found safer than the richer sorts, and should 
therefore form a considerable part of the mixtures of these descriptions. 
The ratio of difference between the hot and cold blast Coed-Talon No. 3, and the 
Coed-Talon No. 2, is considerable. In the No. 2 we have the hot blast in the trans- . 
yerse strain a mere fraction stronger, and its power to sustain impact as 1000 to 
1234. On the other hand, the No. 3 cold blast stands prominently forward in the 
ratio of 1000 to 927 for the transverse strength, and 1000 to 925 for the resistance to 
impact. I offer no opinion as to the cause of these discrepancies ; they are correctly 
given in the experiments, and I must leave the reader to draw his own conclusions, 
