ON STRENGTH AND PROPERTIES OF CAST IRON. Ald 
General Summary of Results, as derived Srom the experiments 
on the transverse strength of hot and cold blast iron. 
Ratio of —_| Ratio of powers 
strength, that to sustain im- 
of the cold blast pact (cold blast! 
being repre- being 1000). 
sented by 1000. 
a 
These irons are from Carron iron ............ No. 2...|1000 : 990-9/1000 : 1005-1 
Mr. Hodgkinson’s4 Devon do. ............., No. 3...}1000 : 1416:9}1000 : 2785-6 
experiments, ...... Buffery do. .........00. No. 1...|1000 : 930-7/1000 : 962+] 
Coed-Talon do.......... No. 2.../1000 : 1007 |1000 ; 1234 
Coed-Talon do.......... No. 3...{1000 : 927 |1000 : 995 
Elsicar and Milton do. ......... 1000 : 818 |1000: 875 
Carron do....ccecccceceee No. 3.../1000 : 1181 |1000 : 1201 
Muirkirk do............. No. 1.../1000 : 927 |1000: 893 
Mean.../1000 : 1024-8/1000 : 1226-3 
The ultimatum of our inquiries made in this way, stand, 
therefore, in the ratio of strength, as 1000 for the cold blast, 
to 10248 for the hot blast; leaving the small fractional dif- 
ference of 24°8 in favour of the hot blast.* 
The relative powers to sustain impact are likewise in fa- 
vour of the hot blast, being in the ratio of 1000 to 1226-3. 
For the ratios of the powers of the hot and cold blast 
irons to resist a transverse strain for an indefinite period of 
time, and for the resisting powers of the same iron under 
variable temperatures, I must refer the reader to the results 
contained in their respective tables, 
* The extraordinary properties of the Devon No. 3 iron in a great measure 
account for the difference which occurs between the strengths, as also the 
comparative powers to resist impact. 
