ON STRENGTH AND PROPERTIES OF CAST IRON. 339 
for testing iron cables belonging to the Corporation of Liver- 
pool. Others were made in the same manner but of smaller 
transverse area; these were broken by means of Mr. Fair- 
bairn’s lever, which was adapted so as to be well suited for the 
purpose. 
The form of casting here used was chosen to obviate the 
theoretical objections made by Tredgold and others against 
the conclusions of former experimenters. 'The results are in 
the following table : 
Results of Experiments on the Tensile Force of Cast Iron. 
. Area of | Break. | Strength oP ‘i 
Patt section| ing | per square} Mean in lbs. per 
Description of Iron. _ in weight} inch of square inch. 
inches. | in }bs, | section. 
—_—_ 
| Carron Iron, No. 2, Hot Blast .....ssescseereee eee] 4°031 | 56000 ions | Tons. cwts. 
Do. do. GO. ccnnnaesns coeseasense 1°7236] 22395 | 12993 $|13505=6 03 
Do. do. GO. sesseveersecseeeeeeee| 1°7037/ 23219 | 13629 
» 
"| Carron Iron No. 2, Cold Blast ..ssscssssseceeess .| 1°7091] 28667 | 16772] |1gg93_7 9 
Do. do. dO. sscseseceeecseseeeeee| 1°6331| 27099 | 16594 i. 
Carron Iron, No. 3, Hot Blast .......cseeseeseeeeee| 1°7023] 28667 | 16840 Be. 
Meer) do, x, | 0; scanesageassusosccons|: 1°6613) 31019 igor f|i755=7 18% 
| arron Iron, No. 3, Cold Blast ......csssseseseeseee| 1°6232) 22699 pi 14900=6 7 
| Do. do. GO. seseeseseeeeeesevevee| 1°6677| 240483 | 14417 
“Devon (Scotland) Iron, No. 3, Hot Blast ..,...|4°269 | 93520) 21907 |21907=9 153 
ee ee 
| Buffery Iron, No, 1, Hot Blast..s.sssssesseseeseeee) 3°835 |51520| 13434 |13434=6 0 
Do. do. Cold Blast ....ssesseseseseee|4°104 | 71680 | 17466 |17466=7 16 
Coed-Talon (North Wales) Iron, No. 2, Hot Blast] 1°586 | 25818} 16279 16676=7 9 
;; Do. do, do. 1645 | 28086 | 17074 (Wiig 
Do. do. Cold Blast| 1-535 | 30102| 19610 
Do. do. do. | 1568 | 28380 Lp de Ars es 
__ Compression, or the power to resist a crushing force.—In 
these experiments I shall confine myself to the resistance of 
short specimens; crushing, with few exceptions, only such as 
will break without bending. And if I should appear to pursue 
this and some other matters beyond the strict limits of the in- 
qu iry respecting the strength of hot and cold blast iron, I trust 
it will be excused, as my wish is to obtain some fixed principles 
where we have nothing but doubt and uncertainty. 
_ The tensile strength of cast iron is still a matter of dispute: 
the few direct experiments by Mr. Rennie and Captain Brown 
4 Z2 
